Mobile folded TELE cameras with uniform image contrast on large image sensors

Abstract

The present disclosure provides a folded Tele camera for a mobile device, comprising a lens including a first lens group (Gl) positioned on a first optical axis (OP1), and a second lens group (G2) positioned on a second optical axis (OP2); an optical path folding element (OPFE) positioned between the first and second lens groups configured to fold the first optical axis (OP1) onto the second optical axis (OP2); an image sensor disposed on the second optical axis to receive an image formed by the first and second lens group through the optical path folding element, the folded telecamera being further configured so that a modulation transfer function at a spatial frequency higher than a Nyquist frequency associated with a pixel sensor pitch of the image sensor cycles / mm varies by less than 20% over a field of view of the camera in static condition.

Description

[0001] MOBILE FOLDED TELE CAMERAS WITH UNIFORM IMAGE CONTRAST ON

[0002] LARGE IMAGE SENSORS

[0003] The presently disclosed subject matter is generally related to the field of digital cameras.

[0004] DEFINITIONS

[0005] In this application and for optical and other properties mentioned throughout the description and figures, the following symbols and abbreviations are used, all for terms known in the art:

[0006] Total track length (TTL): the maximal distance, measured along an axis parallel to the optical axis of a lens, between a point of the front surface Si of a first lens element Li and an image sensor, when the system is focused to an infinity object distance. In a folded camera configuration, the TTL may refer to a sum of an optical system length along an object side optical axis (TTL1) and an optical system length along an image side optical axis (TTL2). It may represent a total effective length of the optical system from the first lens surface to the image sensor, as measured along the folded optical axis.

[0007] Back focal length (BFL): the minimal distance, measured along the optical axis of a lens, between a point of the rear surface S2N of the last lens element LN and an image sensor, when the system is focused to an infinity object distance.

[0008] Effective focal length (EFL): in a lens (assembly of lens elements Li to LN), the distance between a rear principal point P' and a rear focal point F' of the lens. f-number (f / #): the ratio of the EFL to an entrance pupil diameter (or simply aperture diameter “DA”).

[0009] BACKGROUND

[0010] Multi-aperture cameras (or “multi-cameras”, of which a “dual-cameras” having two cameras is an example) are today’s standard for portable electronic mobile devices (“mobile devices”, e.g. smartphones, tablets, etc.). A multi-camera usually comprises a wide field-of- view (or “angle”) FOVw camera (“Wide” camera or “W” camera) of about 20mm - 40mm 35mm equivalent focal length (“35eq.FL”), and at least one additional camera, e.g. with a narrower (than FOVw) FOV (Telephoto or “Tele” camera with FOVT) of about 40mm - 300mm 35eq.FL, or with an ultra-wide field of view FOVuw (wider than FOVw, “UW” camera) of about 9mm - 20mm 35eq.FL. FIG. 1A illustrates a known dual-camera 150 that comprises a folded Tele camera 100 having a FOVT and a (vertical or upright) Wide camera 130. Folded Tele camera 100 comprises an optical path folding element (OPFE) 102, a lens 104 (not visible in this representation, see FIG. IB) included in a lens barrel 110 and an image sensor 106. Wide camera 130 includes a lens 132 with a plurality of lens elements (not visible in this representation) and an image sensor 138 having a (full) sensor diagonal (“SD”, marked in FIG. IB). Lens 132 is included in and fixedly coupled to a lens barrel 134. Wide camera 130 has an optical axis 136.

[0011] FIG. IB exemplarily shows lens 104 and image sensor 106 of folded Tele camera 100 in a diagonal cross-sectional view. FIG. 1C exemplarily shows image sensor 106 of folded Tele camera 100 in a top view. Lens 104 forms an image on image sensor 106. FIG. IB shows a first pair of “on-axis” (or “zero-field“) rays 112 impinging on a center of image sensor 106 as well as a second pair of “off-axis” rays 114 impinging on an edge of image sensor 106. An image quality (“IQ”) of the image may be for example described by means of a “Modulation Transfer Function” (“MTF”). The MTF is a measure for a lens’ ability to provide image contrast for a given spatial frequency, i.e. for a given minimum feature size in a scene. The IQ varies for different locations within FOVT, i.e. the IQ is non-uniform. For fixed focal length cameras as disclosed herein, there is an unambiguous relationship between a location within FOVT and a corresponding location at image sensor 106. Here and in the following, we use these terms interchangeably. In general, the IQ is maximum at the center of image sensor 106, and it degrades towards the edges (or “margins”) of image sensor 106. For example, at a same illumination level of a scene, on-axis rays 116 may form a crisper (or “sharper”) image than “off-axis” rays 118. A smallest spatial frequency that should be supported by lens 104 may be defined by a pixel size of pixels included in image sensor 106. The pixel size is in general constant (or “uniform”) over the entire image sensor. Often, a lens such as lens 104 is designed so that it resolves (or “supports” i.e. sharply image details as small as one pixel) a pixel size of pixels at the center of image sensor 106, but not necessarily at the edges of image sensor 106. Exemplarily, in FIG. IB a center region where the pixel size is resolved is marked 116. Edge regions where the pixel size is not resolved are marked as edge regions 118.

[0012] BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Non-limiting examples of embodiments disclosed herein are described below with reference to figures attached hereto that are listed following this paragraph. The drawings and descriptions are meant to illustrate and clarify embodiments disclosed herein, and should not be considered limiting in any way. FIG. 1 A illustrates a known dual-camera in a perspective view;

[0014] FIG. IB schematically illustrates a known Tele camera including a lens and an image sensor in a diagonal cross-sectional view;

[0015] FIG. 1C schematically illustrates the image sensor of FIG. IB in a top view;

[0016] Fig. 2A illustrates a reference optical lens system disclosed herein;

[0017] Fig. 2B illustrates a modulation transfer function (MTF)-vs-Field graph of the lens optical lens system of Fig. 2A;

[0018] Fig. 2C illustrates another reference optical lens system disclosed herein;

[0019] FIG. 3 A schematically illustrates a Tele camera disclosed herein and including a lens and an image sensor in a diagonal cross-sectional view;

[0020] FIG. 3B schematically illustrates the image sensor of FIG. 3 A in a top view;

[0021] Fig. 4A illustrates an optical lens system disclosed herein;

[0022] Fig. 4B illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 4A;

[0023] Fig. 5A illustrates another optical lens system disclosed herein;

[0024] Fig. 5B illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 5 A;

[0025] Fig. 6A illustrates yet another optical lens system disclosed herein;

[0026] Fig. 6B illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 6A;

[0027] Fig. 7A illustrates yet another optical lens system disclosed herein;

[0028] Fig. 7B illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 7A;

[0029] Fig. 8A illustrates yet another optical lens system disclosed herein;

[0030] Fig. 8B illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 8 A;

[0031] Fig. 9A illustrates yet another optical lens system disclosed herein;

[0032] Fig. 9B illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 9A;

[0033] Fig. 10A illustrates yet another optical lens system disclosed herein;

[0034] Fig. 10B illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 10A.

[0035] Fig. 11 A illustrates yet another optical lens system disclosed herein;

[0036] Fig. 1 IB illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 11 A.

[0037] Fig. 11C illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 11A when performing optical image stabilization in a first direction;

[0038] Fig. 11D illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 11A when performing optical image stabilization in a second direction;

[0039] Fig. HE illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. HA when focused to a distance of Im;

[0040] Fig. 1 IF illustrates a MTF-vs-Field graph of the lens optical lens system of Fig. 11A when focused to a distance of 50cm.

[0041] DETAILED DESCRIPTION

[0042] It would be beneficial to have folded Tele cameras that have a relatively uniform MTF and which are capable of resolving a pixel size over an entire FOVT or at least a significant part thereof (e.g. 80%, 85%, 90%, 95%, 99%). Such folded Tele cameras are disclosed herein.

[0043] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding. However, it will be understood by those skilled in the art that the presently disclosed subject matter may be practiced without these specific details. In other instances, well-known methods and features have not been described in detail so as not to obscure the presently disclosed subject matter.

[0044] In the present application, tables and corresponding figures detail lens-element parameters of different lens elements, for different exemplary embodiments. The following definitions and parameters may be used throughout the different exemplary embodiments: The surface types are: a) Plano: flat surfaces, no curvature. b) Q type 1 (QT1) surface sag formula:

[0045] Qo°n(x) = 1 Q‘on= -(5 - 6x) Q^on= 15 - 14x(3 - 2%)

[0046] Q^on= -{35 - 12x[14 - x(21 - 10x)]}

[0047] Qcon=70 > 3%{168 - 5x[84 - llx(8 - 3x)]}

[0048] Qcon=_[126>x(1260- llx{420 - x[720 - 13x(45 - 14x)]})] etc. c) Even Asphere (ASP) surface sag formula: where {z, r} are the standard cylindrical polar coordinates, c is the paraxial curvature of the surface, k is the conic parameter, rnOrm is generally one half of the surface’s clear aperture, Pn(0,4)are the Jacoby polynomials Pn(a,P)of parameters a=0 and =4. An(QT1 surfaces) and / or an(ASP surfaces) are the sag polynomial coefficients shown in the lens data tables.

[0049] Values for a clear-aperture, a term known in the art, may be denoted “CA”, and may be given as a clear aperture radius, i.e., as CA / 2.

[0050] A reference wavelength may be 555.0 nm.

[0051] Values representing length may be provided in millimetres, except for refraction index (“Index”) and Abbe #, that are unit-less.

[0052] Each lens element Li may have a respective focal length fi.

[0053] An FOV may be given as a half FOV (HFOV). The Tables may provide the clear aperture radius of an OPFE (for example, in Fig.2A, prism 204). The CA radius may represent a circular optical active area of an OPFE.

[0054] Due to a change in direction introduced by the optical path folding element (OPFE), such as a reflective prism or mirror, the term folded optical axis may refer to an optical path that includes a first segment extending from the object-side entrance of the camera to the OPFE (also referred to as object side optical axis or “y-axis”), and a second segment extending from the OPFE to the image sensor (also referred to as image side optical axis or “z-axis”). For clarity, an origin of the z-axis (z = 0) may be defined to coincide with the image sensor plane.

[0055] In the notation used herein, a prefix H, W and the like followed by a component name (e.g., HOPFE or WGI) may denote an attribute (e.g. height measured along the y-axis, width measured the z-axis) of the component measured.

[0056] For the sake of clarity, similar or functionally equivalent elements may be denoted by reference numbers sharing the same last two digits, with the leading digit varying by embodiment (e.g., elements 204 and 304 may represent analogous components in designs 200 and 300, respectively).

[0057] The disclosed embodiments can generally be grouped into two sets, each based on improvements made to a different baseline optical configuration. A first set of embodiments is based on a reference optical design shown in FIG. 2A (lens system 200), which serves as a reference layout for the embodiments illustrated in FIGs. 4A (lens system 400), 5A (lens system 500), 6A (lens system 600), and 7A (lens system 700).

[0058] The first set of embodiments encompasses generally a folded Tele camera for a mobile device, comprising: a lens including a first lens group positioned on a first optical axis, and a second lens group positioned on a second optical axis comprising at least five lens elements, and the first lens group comprises fewer lens elements than the second lens group; an optical path folding element (e.g. prism) positioned between the first and second lens groups configured to fold the first optical axis onto the second optical axis; an image sensor disposed on the second optical axis to receive an image formed by the first and second lens group through the optical path folding element, the image sensor having a full image sensor diagonal (SD) in the range of 4mm - 20mm. The folded telecamera is further configured so that: (i) an effective focal length is in the range of 8mm - 40mm; (ii) a total track length satisfies TTL / EFL<1.5; (iii) a largest air gap d between adjacent lens elements satisfies d / TTL>0.15; (iv) a modulation transfer function at a spatial frequency higher than a Nyquist frequency corresponding to the image sensor pixel pitch (e.g. 150 cycles / mm) varies by less than a predefined threshold (e.g. 20%) over a core field of view of the camera. Additional features of the first set of embodiments are presented below.

[0059] A second set of embodiments is based on another reference optical design shown in FIG. 2C (lens system 250), and includes the embodiments illustrated in FIGs. 8A (lens system 800), 9A (lens system 900), 10A (lens system 1000), and 11 A (lens system 1100). In both sets, elements that serve similar or corresponding functions are labelled using consistent two-digit suffixes, with the leading digit indicating the associated figure and embodiment.

[0060] The second set of embodiments encompasses generally a folded Tele camera for a mobile device, comprising: a lens including a first lens group positioned on a first optical axis, and a second lens group comprising at least one lent element positioned on a second optical axis, the second lens group comprising fewer lens elements than the first lens group; an optical path folding element (e.g. a prism) positioned between the first and second lens groups configured to fold the first optical axis onto the second optical axis; an image sensor disposed on the second optical axis to receive an image formed by the first and second lens group through the optical path folding element, the image sensor having a full image sensor diagonal in the range of 4mm - 20mm. The folded Tele camera is further configured so that: (i) an effective focal length is in the range of 10mm - 20mm; (ii) atotal tracklength satisfies TTL / EFL<1.2; (iii) a modulation transfer function at a spatial frequency higher than a Nyquist frequency corresponding to the image sensor pixel pitch (e.g. 200 cycles / mm) varies by less than a predetermined threshold (e.g. 20%) over a core field of view of the camera. Additional features of the second set of embodiments are presented below.

[0061] An optical system may be said to have uniform modulation-transfer function when, at (and from) a predefined spatial frequency (e.g., the Nyquist frequency of the target image sensor), the MTF at any point within a core field of view - that may be defined as covering a predefined portion of the full field of view (e.g. 80%, 85%, 90%, 95%, 99% or 100%) - deviates by no more than a predefined threshold (e.g. 10%, 15% or 20%) from the on-axis MTF under static conditions. During operation of optical image stabilization (OIS) and / or autofocus (AF), the MTF may vary within an extended threshold (e.g., 30%, 35% or 40%) over a reduced portion of the core field of view (e.g., the central 30%, 40%, 50%, or 60% of the field of view), while falling outside this range in the peripheral regions.

[0062] Furthermore, the MTF at a point may be defined as an average of a sagittal modulation transfer value and tangential modulation transfer value at said point in the FOV.

[0063] For estimating theoretical limits for minimum (or “optical”) dimensions of a camera module that includes optical lens systems described herein, referring to Fig. 2A as an example, the following parameters and interdependencies are introduced:

[0064] “Camera module length” (“LM”):

[0065] The Minimum (or “optical”) module length (“MLM” or “ML”) may refer to a theoretical limit for a length measured along the z-axis of a camera module that includes all components of cameras disclosed herein such as camera 200, 250, 400, 500, 600, 700, 800, 900, 1000 and 1100.

[0066] MLM = max(ZLens, ZOPFE) - Zsensor, max(ZLens, ZQPFE) being the maximum z-value of a lens group such as 202-G1 (ZLCHS) or OPFE 204 (ZOPFE) and Zsensor being the minimum z-value of image sensor 206. The z-values may refer to positions (coordinates) along the z-axis. The z-value of an element may refer to a maximum axial position of the element along the z-axis. In some embodiments and as shown in Fig. 2A, ZLCHS > ZOPFE, SO that MLM = ZL ens " Zsensor-

[0067] For achieving a realistic estimation for the Camera module length (LM), one may add for example a length of 3.5mm to MLM, i.e., LM = MLM +3.5mm. The additional length accounts for a lens stroke that may be required for optical image stabilization (OIS) as well as for image sensor packaging, housing, etc.

[0068] R1 - A first region (“Rl” also referred to as camera head) of the camera may be defined over the z-axis. Rl may refer to a camera portion extending from a frontmost optical surface to an exit surface of the optical-path-folding element (OPFE) through which light exits towards the image sensor.

[0069] A z-axial extent corresponding to the first region may be given by Rl = max(Wp, WOPFE), where WL and WOPFE may respectively refer to a z-axial extent of the frontmost lens group G1 and OPFE i.e. width of the elements along the z-axis. In some embodiments and as shown in Fig. 2A, WL > WOPFE, SO that Rl is determined solely by 202-G1 and Rl = WL. The first region Rl may be associated with a first module height denoted MHM “Minimum Module Height”. R2 - A second region (“R2” also referred to as camera shoulder) of the camera may be defined over the z-axis. The second region R2 may refer to a camera portion extending from the exit surface of the OPFE to the image sensor. The second region R2 may be associated with a second module height denoted MHs “Minimum Shoulder Height”, wherein MHs <MHM.

[0070] A z-axial extent corresponding to the second region may be given by R2 = MLM-R1 .

[0071] In general, and for a given MLM, from an industrial design point of view it may be beneficial to maximize R2 (minimize Rl).

[0072] MHMand “Module height” (“HM”) -

[0073] The Minimum Module Height i.e. the minimum (i.e. based on optical considerations only) y-axial extent of the first region may be given by

[0074] MHM = HQPFE + ALO + TGI.

[0075] Wherein:

[0076] - HQPFE defines a minimum extent of the OPFE over the y-axis required to intercept and redirect the bottom-most ray of light entering the optical system along the optical axis. The OPFE may extend above this height but, theoretically, may also be cut or truncated below the HQPFE without compromising the ability to reflect said bottom-most on-axis ray;

[0077] ALO refers to an air gap between the bottom-most surface of the first lens group and the OPFE;

[0078] TGI refers to a thickness along the y-axis of the first lens group.

[0079] For achieving a realistic estimation for a camera module height, we calculate a camera module height HM by adding an additional height of 1 ,5mm to MHM, i.e., HM = MHM + 1.5mm. The additional length accounts for housing, lens cover, etc that may be included in the camera module.

[0080] In other examples, e.g., with an image sensor 206 occupying a lower y-value than OPFE 204 (e.g. when the OPFE deflects lights by more than 90 degrees or in case of large sensors), MHM may be greater than HQPFE + ALO + TGI. In these examples, MHM is given by the difference between the lowest y-values occupied by image sensor 206 and the highest y-value occupied by 202-G1.

[0081] MHs and “Shoulder height” (“Hs”) - A second minimum module height (“MHs”) or “Minimum Shoulder Height” may refer to a theoretical (i.e. based on optical considerations only) limit for a y-axis extent of the second region R2 of the camera module. . The Minimum Shoulder Height may be given by

[0082] MHs - min(Hs, HQPFE, HRAYS) Wherein HRAYS may refer to a full field height measured along the y-axis of the on-axis ray envelope at the image sensor plane i.e. a distance between an uppermost and lowermost ray intercepts on the sensor plane.

[0083] In some embodiments, MHs may be determined solely by the distance between a lowest ray and a highest rays on the sensor 206, whereas “low” and “high” refer to a value along a height axis (y-axis). Image sensor 206 may have a width (SW) : height (SH) ratio of 4:3, so that a sensor diagonal (SD) can be calculated from a sensor height (SH) by SD=5 / 3-SH.

[0084] In some embodiments, for example, as shown in Fig. 2A, MHs may be determined solely by image sensor 206, i.e., MHs = SH.

[0085] For achieving a realistic estimation for a real camera module height, shoulder height Hs is calculated by adding an additional height of, for example, 1.5mm to MHs, i.e., Hs = MHs +1.5mm. The additional height accounts for contacting sensor 206 as well as for housing.

[0086] Herein, two types of optical lens systems are disclosed. Both types are folded optical lens systems including an (single) OPFE.

[0087] A first type of reference optical lens system is referred to as “2-group” (“2G”) optical lens systems. A 2G optical lens system is characterized by the fact that a lens included in the optical lens system is divided into 2 lens groups: A first lens group (“Gl”) (optionally including a single lens) located at an object side of the OPFE and having a first optical axis and a second lens group (“G2”) located at an image side of the OPFE and having a second optical axis. Optical lens system 200 is a 2G optical lens system. Lens systems of the first set of embodiments may include up to one single lens on the object side of the OPFE. The OPFE may fold the optical axis by more than 90 degrees and optionally by less than 95 degrees. A largest air gap d, located optionally between a penultimate lens element and an ultimate lens element of the second lens group, satisfies d / TTL>0.15.

[0088] It has been found that a large gap, located optionally between the two last lens elements of the second lens group, is beneficial for enabling a more uniform MTF over the field of view.

[0089] A second type of reference optical lens system is referred to as “1 -group” (“1G”) optical lens systems. A 1G optical lens system is characterized by the fact that a lens included in the optical lens system is located at an object side of the OPFE. Optical lens system 250 is a 1G optical lens system. Lens systems of the second set of embodiments may include up to one lens on the image side of the OPFE. The OPFE may fold the optical axis by 90 degrees.

[0090] Values and dimensions of a camera and a mobile device including all optical lens systems disclosed herein and based on 2G optical lens system 200 are presented in Table 1. Table 1 uses the definitions and explanations given above and in FIGS. 2A, 4 A, 5 A, 6 A and 7 A. All sizes as well as EFL and 35mm Eq FL is given in mm, HFOV is given in degrees.

[0091] We note that compared to reference optical lens system 200, all optical lens systems 400, 500, 600 and 700 have a relatively uniform MTF and are capable of resolving a pixel size over an entire FOVT, i.e. a MTF decrease at a spatial frequency of 208cy / mm is less than about 20%. We also note that the more uniform MTF is obtained while preserving a relatively low MHM. An increase of MHM with respect to reference optical lens system 200 is by 7.5% or less.

[0092] A relative illumination at an image margin (“RIM”) is measured at an image height of

[0093] 6.1mm.

[0094] MTFM and AMTF (%) are based on visual estimations

[0095] Table 1

[0096] Values and dimensions of a camera and a mobile device including all optical lens systems disclosed herein and based on 1G optical lens system 250 are presented in Table 2. Table 2 uses the definitions and explanations given above and in FIGS. 2C, 8 A, 9 A, 10 A, and 11 A.

[0097] We note that compared to reference optical lens system 250, all optical lens systems 800, 900, 1000 and 1100 have a relatively uniform MTF and are capable of resolving a pixel size over an entire FOVT, i.e. a MTF decrease at a spatial frequency of 313cy / mm is less than about 20%. We also note that the more uniform MTF is obtained while preserving a relatively low MHM. An increase of MHM with respect to reference optical lens system 250 is by 7.5% or less. Also an increase of MHS with respect to reference optical lens system 250 is relatively low. The increase in HMS is caused by a larger OPFE. RIM is measured at an image height of 4.4mm. and AMTF (%) are based on visual estimations

[0098]

[0099] Table 2

[0100] Fig. 2A illustrates an embodiment of a reference optical lens system numbered 200. Lens system 200 is described in Fig. 4 and as embodiment 400 in co-owned International Patent Application PCT / IL2025 / 050123. Herein, lens system 200 represents a reference lens for lens systems 400, 500, 600 and 700, which all are based on, and have similar optical parameter and dimensions, as lens system 200. Lens system 200 is shown focused to infinity. Lens system 200 may comprise a lens 202, an OPFE (here, a prism) 204, an optical element 207 and an image sensor 206. System 200 is shown with ray tracing. Optical element 207 is optional and may be, for example, an infra-red (IR) filter, and / or a glass image sensor dust cover. Lens 202 may be divided in two lens groups, 202-G1 that includes Li (“Gl”), and 202-G2 that includes a plurality of lenses e.g. 6 lenses L2 - L7 (“G2”). Optical rays that pass through 202-G1 may be reflected by prism 204, may pass through 202-G2, and may form an image on the image sensor 208. Lens 202 may include a plurality of N = 7 lens elements. The single lens element of 202- G1 may be axial-symmetric along a first optical (lens) axis OP1. The 6 lens elements of 202- G2 may be axial-symmetric along a second optical (lens) axis OP2. Fig. 2A shows 3 fields (image points) with 3 rays for each. On-axis rays are marked 212, off-axis rays are marked 214.

[0101] Detailed optical data and surface data are given in Tables 3-4 for the example of the lens elements in Fig. 2A. The values provided for these examples are purely illustrative and according to other examples, other values can be used.

[0102] Prism 204’s light entrance surface 205 is oriented parallel to OP2 212. Prism 204’s internal prism angle marked a = 43.7 degrees. Prism 204’s light exiting surface 207 is oriented so that a central (or “zero-field”) ray impinges perpendicular onto light exiting surface 207. An angle between OP1 208 and OP2212 is about 88 degrees. In other examples, an angle between OP1 208 and OP2 212 may be in the range of 80 degrees to 90 degrees, for example in the range of 85 degrees to 88 degrees.

[0103] FIG. 2B shows a MTF-vs-Field graph 220 of lens optical lens system 200. Graph 220 shows the value of an MTF for a spatial frequency of 208cy / mm along the y-axis for a camera angle or FOV along the x-axis.

[0104] In FIG. 2B as well as in the other MTF-vs-Field graphs, the horizontal axis represents the field in millimeters across the image sensor diagonal measured from the optical axis (center) toward the periphery and the vertical axis represents the MTF value at a given field position. Furthermore, the solid line corresponds to the sagittal MTF (MTF measured along lines parallel to the radial direction) and the dashed line, corresponds to the tangential MTF (MTF measured along lines perpendicular to the radial direction).

[0105] The MTF’s spatial frequency of 208cy / mm corresponds to a pixel size of about 1.2um. We find that a MTF is about 0.61 in a center region (“MTFc”), where on-axis rays 212 impinge on image sensor 206, and about 0.41 in a margin region (“MTFM”), where off-axis rays 214 impinge on image sensor 206. There is an intermediate region 216 where a MTF is about 0.50 (“MTFi”), and which expands from about 2mm to 4mm. There is a significant MTF reduction from the center region to the margin region of about 33%. The IQ varies for different locations within FOVT, i.e. the IQ is non-uniform.

[0106] Table 3

[0107] End of Table 3

[0108] Table 4

[0109]

[0110] Table 4 cont.

[0111] End of Table 4

[0112] Fig. 2C illustrates an embodiment of an optical lens system disclosed herein and numbered 250. Lens system 250 represents a reference lens for lens systems 800, 900, 1000 and 1100, which all are based on, and have similar optical parameter and dimensions, as lens system 250. Lens system 250 is shown focused to infinity. Lens system 250 may comprise a lens 252, an OPFE (here, a prism) 254, an optical element 257 and an image sensor 256. Optical element 257 is optional. Lens 252 is located at an object side of OPFE 254. Optical rays that pass through lens 252, may be reflected by prism 254 and may form an image on the image sensor 256. Lens 252 may include a plurality of N = 4 lens elements and may be axial- symmetric along a first optical (lens) axis OP1. Fig. 2C shows 5 fields (image points) with 3 rays for each. On-axis rays are marked 262, off-axis rays are marked 264. Detailed optical data and surface data are given in Tables 5-6 for the example of the lens elements in Fig. 2C. Prism 254’s light entrance surface 255 is oriented parallel to OP2. Prism 254’s internal prism angle is 45 degrees. Prism 254’s light exiting surface 257 is oriented parallel to OP1. In other examples, prism 254’s internal prism angle may be less than 45 degrees, e.g. it may be in the range of 40 - 45 degrees. An angle between OP1 and OP2 is about 90 degrees. In other examples, an angle between OP1 and OP2 may be in the range of 80 degrees to 90 degrees, for example in the range of 85 degrees to 88 degrees.

[0113] In lens optical lens system 250, there is a significant MTF reduction from a center region to a margin region. MTFM, where off-axis rays 264 impinge on image sensor 256, may be lower than MTFc, where on-axis rays 262 impinge on image sensor 256, by more than 50%. The IQ is non-uniform.

[0114] Prism entrance surface (S12) is rectangular and has a rectangular surface aperture (x,y)=(5.0,4.55). Prism exitance surface (S14) is rectangular and has a rectangular surface aperture (x,y)=(5.0,4.55).

[0115] Table 5

[0116] End of Table 5

[0117] Table 6

[0118] Table 6 cont. FIG. 3A exemplarily shows a lens as disclosed herein and marked 302 and an image sensor 304 of a folded Tele camera as disclosed herein in a diagonal cross-sectional view. FIG. 3B exemplarily shows image sensor 304 in a top view. Lens 302 forms an image on image sensor 304. FIG. 3 A shows a first pair of on-axis rays 306 impinging on a center of image sensor 304 as well as a second pair of off-axis rays 308 impinging on an edge of image sensor 304. The IQ does not vary significantly for different locations within FOVT, i.e. the IQ is uniform, which is beneficial. The IQ does not degrade significantly towards the edges of image sensor 304. Lens 302 is designed so that it resolves a pixel size of pixels at any position within the FOV, i.e. not just at the center of image sensor 304, but also at the edges of image sensor 304. Such lenses are disclosed in the following.

[0119] Fig. 4A schematically illustrates another embodiment of an optical lens system disclosed herein and numbered 400. Lens system 400 may comprise a lens 402, an OPFE 404, an optical element 407 and an image sensor 406. Lens 402 is divided in 402-G1 that includes Li, and 402-G2 that includes L2 - L7. The single lens element of 402-G1 may be axial- symmetric along OP1. The 6 lens elements of 402-G2 may be axial-symmetric along OP2. On- axis rays are marked 412, off-axis rays are marked 414.

[0120] Detailed optical data and surface data are given in Tables 7-8 for the example of the lens elements in Fig. 4A. The values provided for these examples are purely illustrative and according to other examples, other values can be used.

[0121] Prism 404’ s light entrance surface is oriented parallel to OP2. Prism 404’ s internal prism angle is a = 43.7 degrees. Prism 404’ s light exiting surface is oriented so that a central ray impinges perpendicular onto the light exiting surface.

[0122] FIG. 4B shows a MTF-vs-Field graph 420 of lens optical lens system 400 for a spatial frequency of 208cy / mm. There is a relatively low MTF reduction of about 10% from the center region to the margin region.

[0123] Lens system 400 has a relatively low maximum chief ray angle (“CRA”) of less than 30 degrees, which is beneficial for achieving a relatively low MTF reduction from the center region to the margin region.

[0124] Table 7

[0125] End of Table 7

[0126] Table 8

[0127] End of Table 8

[0128] Fig. 5A schematically illustrates another embodiment of an optical lens system disclosed herein and numbered 500. Lens system 500 may comprise a lens 502, an OPFE (here, a prism) 504, an optical element 507 and an image sensor 506. System 500 is shown with ray tracing. Optical element 507 is optional. Lens 502 may be divided in 502-G1 that includes Li, and 502-G2 that includes L2 - L7. Lens 502 may include a plurality of N = 7 lens elements. The single lens element of 502-G1 may be axial-symmetric along OP1. The 6 lens elements of 502-G2 may be axial-symmetric along OP2. On-axis rays are marked 512, off-axis rays are marked 514. Detailed optical data and surface data are given in Tables 9-10 for the example of the lens elements in Fig. 5A. The values provided for these examples are purely illustrative and according to other examples, other values can be used.

[0129] Prism 504’s light entrance surface 505 is oriented parallel to OP2 512. Prism 504’s internal prism angle is a = 43.7 degrees. Prism 504’s light exiting surface 507 is oriented so that a central ray impinges perpendicular onto light exiting surface 507.

[0130] FIG. 5B shows a MTF-vs-Field graph 520 of lens optical lens system 500 for a spatial frequency of 208cy / mm. There is a relatively low MTF reduction of about 15% from the center region to the margin region.

[0131] Table 9

[0132] End of Table 9

[0133] Table 10

[0134] End of Table 10

[0135] Fig. 6A schematically illustrates another embodiment of an optical lens system disclosed herein and numbered 600. Lens system 600 may comprise a lens 602, an OPFE (here, a prism) 604, an optical element 607 and an image sensor 606. System 600 is shown with ray tracing. Optical element 607 is optional. Lens 602 may be divided in 602-G1 that includes Li, and 602-G2 that includes L2 - Ls. Lens 602 may include a plurality of N = 8 lens elements. The single lens element of 602-G1 may be axial-symmetric along OP1. The 7 lens elements of 602-G2 may be axial-symmetric along OP2. On-axis rays are marked 612, off-axis rays are marked 614.

[0136] Detailed optical data and surface data are given in Tables 11-12 for the example of the lens elements in Fig. 6A. The values provided for these examples are purely illustrative and according to other examples, other values can be used.

[0137] Prism 604’s light entrance surface 605 is oriented parallel to OP2 612. Prism 604’s internal prism angle is a = 43.7 degrees. Prism 604’s light exiting surface 607 is oriented so that a central ray impinges perpendicular onto light exiting surface 607.

[0138] FIG. 6B shows a MTF-vs-Field graph 620 of lens optical lens system 600 for a spatial frequency of 208cy / mm. A MTF is 0.59 in a center region and 0.51 in a margin region. The IQ degrades slightly towards the edges, but is still relatively uniform. Table 11

[0139] End of Table 11

[0140] Table 12

[0141] End of Table 12

[0142] Fig. 7A schematically illustrates another embodiment of an optical lens system disclosed herein and numbered 700. Lens system 700 may comprise a lens 702, an OPFE (here, a prism) 704, an optical element 707 and an image sensor 706. System 700 is shown with ray tracing. Optical element 707 is optional. Lens 702 may be divided in 702-G1 that includes Li, and 702-G2 that includes L2 - Ls. Lens 702 may include a plurality of N = 8 lens elements. The single lens element of 702-G1 may be axial-symmetric along OP1. The 7 lens elements of 702-G2 may be axial-symmetric along OP2. On-axis rays are marked 712, off-axis rays are marked 714.

[0143] Detailed optical data and surface data are given in Tables 13-14 for the example of the lens elements in Fig. 7A. The values provided for these examples are purely illustrative and according to other examples, other values can be used.

[0144] Prism 704’s light entrance surface 705 is oriented parallel to OP2 712. Prism 704’s internal prism angle is a = 43.7 degrees. Prism 704’s light exiting surface 707 is oriented so that a central ray impinges perpendicular onto light exiting surface 707.

[0145] FIG. 7B shows a MTF-vs-Field graph 720 of lens optical lens system 700 for a spatial frequency of 208cy / mm. There is a relatively low MTF reduction of about 18% from the center region to the margin region. Table 13

[0146] End of Table 13

[0147] Table 14

[0148] End of Table 14

[0149] Fig. 8A schematically illustrates another embodiment of an optical lens system disclosed herein and numbered 800. Lens system 800 may comprise a lens 802, an OPFE 804, an optical element 807 and an image sensor 806. Lens 802 is divided in 802-G1 that includes L1-L4 and 802-G2 that includes L5. 802-G1 may be axial-symmetric along OP1. L5 may be axial-symmetric along OP2. In other examples, 802-G2 may include more than one lens element. In some examples, L5 may be a cut lens that is cut along an axis parallel to OP2. The cutting may be beneficial for achieving a relatively low MHS. On-axis rays are marked 812, off-axis rays are marked 814. With respect to reference optical lens system 250, the additional lens group along OP2 in optical lens system 800 allows for providing a more uniform MTF. We note that L5 has two curved (or “non-planar”) surfaces, S15 and S16.

[0150] Detailed optical data and surface data are given in Tables 15-16 for the example of the lens elements in Fig. 8A.

[0151] Prism 804’ s light entrance surface is oriented parallel to OP2. Prism 804’ s internal prism angle is 45 degrees. Prism 804’s light exiting surface is oriented perpendicular to OP2. In other examples, an internal prism angle may be smaller than 45 degrees, e.g. 42 - 44 degrees, so that an angle between OP1 and OP2 is smaller than 90 degrees, e.g. 82 deg - 88 deg.

[0152] FIG. 8B shows a MTF-vs-Field graph 820 of lens optical lens system 800 for a spatial frequency of 313cy / mm. The MTF’s spatial frequency of 313cy / mm corresponds to a pixel size of about 0.8um. There is a relatively low MTF reduction of about 14% from the center region to the margin region.

[0153] Prism entrance surface (S12) is rectangular and has a rectangular surface aperture (x,y)=(5.4,5.0). Prism exitance surface (S15) is rectangular and has a rectangular surface aperture (x,y)=(5.4,5.0).

[0154] Table 15

[0155] End of Table 15

[0156] Table 16

[0157] Table 16 cont.

[0158] Fig. 9A schematically illustrates another embodiment of an optical lens system disclosed herein and numbered 900. Lens system 900 may comprise a lens 902, an OPFE 904, an optical element 907 and an image sensor 906. Lens 902 is divided in 902-G1 that includes L1-L4 and 902-G2 that includes L5. 902-G1 may be axial-symmetric along OP1. L5 may be axial-symmetric along OP2. In other examples, 902-G2 may include more than one lens element. On-axis rays are marked 912, off-axis rays are marked 914. With respect to reference optical lens system 250, the additional lens group along OP2 in optical lens system 900 allows for providing a more uniform MTF. We note that L5 has one planar surface (SI 5) and one curved surface (SI 6). A planar S15 may allow to attach L5 (or “fixedly couple to”) to OPFE 904.

[0159] Detailed optical data and surface data are given in Tables 17-18 for the example of the lens elements in Fig. 9A.

[0160] Prism 904’ s light entrance surface is oriented parallel to OP2. Prism 904’ s internal prism angle is 45 degrees. Prism 904’ s light exiting surface is oriented perpendicular to OP2.

[0161] FIG. 9B shows a MTF-vs-Field graph 920 of lens optical lens system 900 for a spatial frequency of 313cy / mm. There is a relatively low MTF reduction of about 8% from the center region to the margin region.

[0162] Prism entrance surface (S12) is rectangular and has a rectangular surface aperture (x,y)=(5.8,5.0). Prism exitance surface (S14) is rectangular and has a rectangular surface aperture (x,y)=(5.9,5.0).

[0163] Table 17

[0164] End of Table 17

[0165] Table 18

[0166] Table 18 cont.

[0167] End of Table 18

[0168] Fig. 10A schematically illustrates another embodiment of an optical lens system disclosed herein and numbered 1000. Lens system 1000 may comprise a lens 1002, an OPFE 1004, an optical element 1007 and an image sensor 1006. Lens 1002 is divided in 1002-G1 that includes L1-L4 and 1002-G2 that includes L5. 1002-G1 may be axial-symmetric along OP1. L5 may be axial-symmetric along OP2. In other examples, 1002-G2 may include more than one lens element. On-axis rays are marked 1012, off-axis rays are marked 1014. With respect to reference optical lens system 250, the additional lens group along OP2 in optical lens system 1000 allows for providing a more uniform MTF. We note that OPFE 1004’s image-sided surface, S14, represents also Ls‘s object-sided surface. Both OPFE 1004’s image-sided surface and Ls‘s object-sided surface are planar. L5 is attached to OPFE 1004. L5 may be made of a material suitable for plastic molding L5 onto OPFE 1004. L5 has one curved surface (SI 5). In some examples, this suitable material may be “Ormocomp”. In some examples, OPFE 1004 and L5 may be made from a same material. In some examples, OPFE 1004 and L5 may be a single unit, referred to as “power prism”. Here, the power prism provides optical power by means of a curved exit (image sided) surface. Using a power prism may be beneficial for achieving a relatively low MHM for a given size of DA, or vice versa for achieving a relatively large for a given module height MHM. This is beneficial for a slim folded camera incorporated in mobile devices such as smartphones. In addition, using a power prism may be beneficial for achieving a relatively low cost, as of its simpler assembly compared to using a separate L5 and prism. This is beneficial for a relatively low-cost folded camera incorporated in mobile devices such as smartphones.

[0169] Detailed optical data and surface data are given in Tables 19-20 for the example of the lens elements in Fig. 10A.

[0170] Prism 1004’s light entrance surface is oriented parallel to OP2. Prism 1004’s internal prism angle is 45 degrees. Prism 1004’s light exiting surface is oriented perpendicular to OP2.

[0171] FIG. 10B shows a MTF-vs-Field graph 1020 of lens optical lens system 1000 for a spatial frequency of 313cy / mm. There is a relatively low MTF reduction of about 11% from the center region to the margin region.

[0172] Prism entrance surface (S12) is rectangular and has a rectangular surface aperture (x,y)=(5.8,5.0). Prism exitance surface (S14) is rectangular and has a rectangular surface aperture (x,y)=(5.8,5.0).

[0173] Table 19

[0174] End of Table 19

[0175] Table 20

[0176] Table 20 cont.

[0177] End of Table 20

[0178] Fig. 11A schematically illustrates another embodiment of an optical lens system disclosed herein and numbered 1100. Lens system 1100 may comprise a lens 1102, an OPFE 1104, an optical element 1107 and an image sensor 1106. Lens 1102 is divided in 1102-G1 that includes L1-L4 and 1102-G2 that includes L5. 1102-G1 may be axial-symmetric along OP1. L5 may be axial-symmetric along OP2. In other examples, 1102-G2 may include more than one lens element. On-axis rays are marked 1112, off-axis rays are marked 1114. With respect to reference optical lens system 250, the additional lens group along OP2 in optical lens system 1100 allows for providing a more uniform MTF. We note that OPFE 1104’s image-sided surface, S14, represents also Ls‘s object-sided surface. L5 is attached to OPFE 1104. L5 may be made of a material suitable for plastic molding L5 onto OPFE 1104. L5 has one curved surface (S16). In some examples, this suitable material may be “Ormocomp”. In some examples, OPFE 1104 and L5 may be a single unit, i.e. a power prism. In some examples, OPFE 1104 and L5 may be made from a same material.

[0179] Detailed optical data and surface data are given in Tables 21-22 for the example of the lens elements in Fig. 11 A.

[0180] Prism 1104’s light entrance surface is oriented parallel to OP2. Prism 1104’s internal prism angle is 45 degrees.

[0181] FIG. 1 IB shows a MTF-vs-Field graph 1120 of lens optical lens system 1100 for a spatial frequency of 313cy / mm. There is a relatively low MTF reduction of about 11% from the center region to the margin region.

[0182] Prism entrance surface (SI 3) is rectangular and has a rectangular surface aperture (x,y)=(6.0,5.0). Prism exitance surface (S16) is rectangular and has a rectangular surface aperture (x,y)=(6.0,5.0). For focusing optical lens systems 800, 900, 100 and 1100 according to a first method, respective lenses 802, 902, 1002 and 1102 and respective OPFEs 804, 904, 1004 and 1104 together may be linearly moved parallel to the z-axis relative to respective image sensors 806, 906, 1006 and 1106. For OIS according to a first method, respective lenses 802, 902, 1002 and 1102 and respective OPFEs 804, 904, 1004 and 1104 together may be linearly moved along a first axis parallel to the y-axis and along a second axis perpendicular to the y-z coordinate system shown, both movements being relative to respective image sensors 806, 906, 1006 and 1106. In other words, lens and OPFE are moved together and relative to the image sensor for focusing and OIS according to the respective first methods. In other examples, the image sensor may be moved relative to the lens and the OPFE for focusing and OIS, referred to as “sensor-shift OIS”.

[0183] For focusing optical lens systems 800, 900, 100 and 1100 according to a second method, respective first lens groups 802 -Gl, 902-G1, 1002-G1 and 1102-G1 may be linearly moved parallel to the y-axis relative to respective OPFEs 804, 904, 1004, and 1104, respective second lens groups 802-G2, 902 -G2, 1002-G2 and 1102-G2 and respective image sensors 806, 906, 1006 and 1106. For OIS according to a second method, respective first lens groups 802-G1, 902-G1, 1002-G1 and 1102-G1 may be linearly moved along a first axis parallel to the y-axis and along a second axis perpendicular to the y-z coordinate system shown, both movements being relative to respective OPFEs 804, 904, 1004, and 1104, respective second lens groups 802-G2, 902-G2, 1002-G2 and 1102-G2 and respective image sensors 806, 906, 1006 and 1106. In other words, the first lens group is moved relative to the OPFE, to the second lens group and to the image sensor for focusing and OIS according to the respective second methods. The OPFE, the second lens group and the image sensor may be kept fixed. The camera may include an actuator coupled to the first lens group (e.g. via a barrel holding the first lens group). The actuator may be configured to displace the first lens group relative to the OPFE, second lens group and image sensor to allow autofocus and OIS. In other words, the actuator may only be operatively coupled to the first lens group. The second method may be beneficial to allow use of more simple actuators for performing the OIS and autofocus capabilities. Optical lens system 1100 may be beneficial for performing focusing and OIS according to the second method while still providing a relatively high MTF.

[0184] FIGS. 11C-D show MTF-vs-Field graphs 1130 and 1140 of lens optical lens system 1100 when performing OIS according to the second method. In FIGS. 11C-D, 1102-G1 is linearly moved along parallel to the y-axis (see Fig. 11 A) so that a rotation of lens optical lens system 1100 by 1 degree is optically compensated. In FIG. 11C, the MTF is measured along an axis parallel to the OIS direction. In FIG. 1 ID, the MTF is measured along an axis normal to the OIS direction. Table 21

[0185] End Table 21

[0186] Table 22

[0187] FIGS. HE and 1 IF illustrate MTF-vs-Field graphs 1150 and 1160 of lens optical lens system 1100 for a spatial frequency of 313cy / mm when performing focusing according to the second method described hereinabove, in which only lens elements of the first lens group located on the object-side of the OPFE element are moved to achieve focus.

[0188] FIG. 1 IE presents the MTF performance of the optical system when focused at a distance of approximately 1 meter, using the second method. It is observed that both sagittal and tangential MTF curves maintain relatively high values near the optical axis (e.g., MTF > 0.4 at field height 0 mm), with gradual degradation occurring as the field height increases. The MTF values remain above approximately 0.3 (corresponding to a 30% drop from the on-axis MTF of -0.45) up to a field height of about ±3 mm (corresponding to about 70% of the FOV). The tangential MTF generally exhibits slightly lower values than the sagittal MTF at the periphery of the field. FIG. 1 IF presents a similar evaluation for the optical system 1100 focused at a closer distance of approximately 50 cm using the second method. The trend is comparable to that in FIG. 1 IE, with sagittal and tangential MTF values remaining above -0.3 up to approximately ±1.76 mm field height (corresponding to about 40% of the FOV). As with FIG. 1 IE, a sharper decline in MTF beyond this field height is noted, especially in the tangential direction. These figures indicate that the system maintains uniform MTF performance within a central region of the image field during focusing via the object-side lens group.

[0189] It is appreciated that certain features of the presently disclosed subject matter, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the presently disclosed subject matter, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[0190] Unless otherwise stated, the use of the expression “and / or” between the last two members of a list of options for selection indicates that a selection of one or more of the listed options is appropriate and may be made.

[0191] It should be understood that where the claims or specification refer to "a" or "an" element, such reference is not to be construed as there being only one of that element.

[0192] All patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present disclosure.

Claims

CLAIMS1. A folded Tele camera for a mobile device, comprising: a. a lens including: i. a first lens group (Gl) positioned on a first optical axis (OP1), and ii. a second lens group (G2) comprising at least one lens element positioned on a second optical axis (OP2), the second lens group comprising fewer lens elements than the first lens group; b. an optical path folding element (OPFE) positioned between the first and second lens groups configured to fold the first optical axis (OP1) onto the second optical axis (OP2); c. an image sensor disposed on the second optical axis to receive an image formed by the first and second lens group through the optical path folding element, the image sensor having a full image sensor diagonal (SD) in the range of 4mm - 16mm; the folded telecamera being further configured so that: i. an effective focal length is in the range of 10mm - 20mm; ii. a total track length satisfies TTL / EFL<1.25; iii. a modulation transfer function at a spatial frequency higher than 200 cycles / mm varies by less than 20% over a core field of view covering 90% of a field of view of the folded Tele camera.

2. The folded Tele camera of claim 1, wherein G2 includes one lens element.

3. The folded Tele camera of claim 1, wherein Gl includes at least four lens elements.

4. The folded Tele camera of claim 1, wherein the second lens group and the OPFE are a single unit.

5. The folded Tele camera of claim 1, wherein a lens element of the second lens group is bonded to an optical path folding element exit surface.

6. The folded Tele camera of claim 1, wherein a lens element of the second lens group is molded? integrally with an optical path folding element exit surface.

7. The folded Tele camera of claim 1, further comprising an actuator coupled to the first lens group and configured to: a. translate the first lens group along the first optical axis relative to the optical path folding element, the second lens group and the sensor, for enabling autofocus; b. translate the first lens group orthogonally to the first optical axis relative to the optical path folding element, the second lens group and the sensor, for enabling optical image stabilization.

8. The folded Tele camera of claim 1 , further comprising an actuator coupled to the first lens group, the optical path folding element and the second lens group and configured to: a. translate the first and second lens groups together with the optical path folding element along the first optical axis for enabling autofocus; b. translate the first and second lens groups together with the optical path folding element orthogonally to the first optical axis for enabling optical image stabilization.

9. The folded Tele camera of claim 1, wherein the modulation transfer function at a spatial frequency larger than 200cy / mm varies by less than 15%.

10. The folded Tele camera of claim 1, wherein the modulation transfer function at a spatial frequency larger than 300cy / mm varies by less than 20%.

11. The folded Tele camera of claim 1, wherein the modulation transfer function at a spatial frequency larger than 300cy / mm varies by less than 15%.

12. The folded Tele camera of claim 1, wherein the lens has a f-number f / # < 3.5.

13. The folded Tele camera of claim 1, wherein the lens has a f-number f / # < 3.

14. The folded Tele camera of claim 1, wherein the lens has a f-number f / # < 2.75.

15. The folded Tele camera of claim 1, wherein the lens has a f-number f / # < 2.5.

16. The folded Telecamera of claim 1, wherein a distance d between the two last lens elements through the optical path folding element satisfies d / TTL>0.15.

17. The folded Telecamera of claim 1, wherein a distance d between the two last lens elements satisfies d / TTL>0.3.

18. The folded Tele camera of claim 1, further configured such that TTL / EFL < 1.1.

19. The folded Tele camera of claim 1, wherein a ratio between the full sensor diagonal and the effective focal length SD / EFL is in the range of 0.4 to 0.7.

20. The folded Tele camera of claim 1, wherein a ratio between the full sensor diagonal and the effective focal length SD / EFL is in the range of 0.5 to 0.6.

21. The folded Tele camera of claim 40, wherein the folded Tele camera is included in a camera module having a first head region with a first minimum module height MHM and a second shoulder region with a second minimum shoulder region height MHS < MHM, both heights measured along the first optical axis.

22. The folded Tele camera of claim 21, wherein a mechanical module height HM of the camera module is given by HM = MHM + 1.5mm, and wherein the folded tele camera is configured such that the mechanical height of the camera module HM < 15mm.

23. The folded Tele camera of claim 22, wherein the folded tele camera is configured such that the mechanical height of the camera module HM < 12.5mm.

24. The folded Tele camera of claim 21, wherein the folded tele camera is configured such that a ratio between the second minimum shoulder region height and the first minimum module height satisfies MHS / MHM < 0.75.

25. The folded Tele camera of claim 21, wherein a ratio MHS / MHM < 0.6.

26. The folded Tele camera of claim 21, wherein SD in the range of 5mm - 12mm.

27. The folded Tele camera of claim 21, wherein SD in the range of 7mm - 9mm.

28. The folded Tele camera of claim 21, wherein EFL is in the range of 12.5mm - 17.5mm.

29. A folded Tele camera for a mobile device, comprising: a. a lens including: i. a first lens group (Gl) positioned on a first optical axis (OP1), and ii. a second lens group (G2) positioned on a second optical axis (OP2), and the first lens group comprises fewer lens elements than the second lens group; b. an optical path folding element (OPFE) positioned between the first and second lens groups configured to fold the first optical axis (OP1) onto the second optical axis (OP2); c. an image sensor disposed on the second optical axis to receive an image formed by the first and second lens group through the optical path folding element, the image sensor having a full image sensor diagonal (SD) in the range of 4mm - 18mm; the folded telecamera being further configured so that: i. an effective focal length is in the range of 8mm - 40mm; ii. a total track length satisfies TTL / EFL<1.5; iii. a largest air gap d between adj acent lens elements satisfies d / TTL>0.15; iv. a modulation transfer function at a spatial frequency higher than 150 cycles / mm varies by less than 20% over a core field of view covering 90% of a field of view of the folded Tele camera.

30. The folded Tele camera of claim 29, wherein the modulation transfer function at a spatial frequency larger than 150cy / mm varies by less than 17.5%.

31. The folded Tele camera of claim 29, wherein the modulation transfer function at a spatial frequency larger than 150cy / mm varies by less than 15%.

32. The folded Tele camera of claim 29, wherein the modulation transfer function at a spatial frequency larger than 150cy / mm varies by less than 12.5%.

33. The folded Tele camera of claim 29, wherein the modulation transfer function at a spatial frequency larger than 200cy / mm varies by less than 20%.

34. The folded Tele camera of claim 29, wherein the modulation transfer function at a spatial frequency larger than 200cy / mm varies by less than 15%.

35. The folded Tele camera of claim 29, wherein the second lens group comprises at least five lens elements.

36. The folded Tele camera of claim 29, wherein the largest air gap d between adjacent lens elements is located between a penultimate lens element and an ultimate lens element of the second lens group.

37. The folded Tele camera of claim 29, wherein the largest air gap d between adjacent lens elements satisfies d / TTL > 0.2.

38. The folded Tele camera of claim 29, further configured such that a back focal length (BFL) satisfies d / BFL > 0. 5.

39. The folded Tele camera of claim 38, further configured such that the back focal length (BFL) satisfies d / BFL > 1.

40. The folded Tele camera of claim 29, further configured such that the back focal length (BFL) satisfies d / BFL > 1.5.

41. The folded Tele camera of claim 29, wherein an angle between OP1 and OP2 is smaller than 90 degrees.

42. The folded Tele camera of claim 29, wherein an angle between OP1 and OP2 is in the range of 85 degrees to 90 degrees.

43. The folded Tele camera of claim 29, further configured such that TTL / EFL < 1.4.

44. The folded Tele camera of claim 29, further configured such that TTL / EFL < 1.35.

45. The folded Tele camera of claim 29, further configured such that a 35mm Eq FL is in the range of 40mm to 120mm.

46. The folded Tele camera of claim 29, further configured such that a 35mm Eq FL is in the range of 60mm to 100mm.

47. The folded Tele camera of claim 29, further configured such that a 35mm Eq FL is in the range of 70mm to 90mm.

48. The folded Tele camera of claim 29, wherein the lens has a f-number f / # < 3.5.

49. The folded Tele camera of claim 29, wherein the lens has a f-number f / # < 3.

50. The folded Tele camera of claim 29, wherein the lens has a f-number f / # < 2.75.

51. The folded Tele camera of claim 29, wherein the lens has a f-number f / # < 2.5.

52. The folded Tele camera of claim 29, wherein a ratio between the full sensor diagonal and the effective focal length SD / EFL is in the range of 0.4 to 0.7.

53. The folded Tele camera of claim 29, wherein a ratio between the full sensor diagonal and the effective focal length SD / EFL is in the range of 0.5 to 0.6.

54. The folded Tele camera of claim 29, wherein G1 includes one lens element.

55. The folded Tele camera of claim 54, wherein the folded Tele camera is included in a camera module having a first head region with a first minimum module height MHM and a second shoulder region with a second minimum shoulder region height MHS < MHM, both heights measured along the first optical axis.

56. The folded Tele camera of claim 55, wherein a mechanical module height of the camera module is given by HM = MHM + 1 ,5mm, and wherein the folded tele camera is configured such that the mechanical height of the camera module HM < 15mm.

57. The folded Tele camera of claim 56, wherein the folded tele camera is configured such that the mechanical height of the camera module HM < 12.5mm.

58. The folded Tele camera of claim 57, wherein the tele camera is configured such that a ratio between the second minimum shoulder region height and the first minimum module height satisfies MHS / MHM < 0.9.

59. The folded Tele camera of claim 54, wherein the folded Tele camera is included in a camera module having a uniform camera module height.

60. The folded Tele camera of claim 54, wherein SD in the range of 8mm - 16mm.

61. The folded Tele camera of claim 54, wherein SD in the range of 10mm - 14mm.

62. The folded Tele camera of claim 54, wherein EFL is in the range of 20mm - 25mm.

63. The folded Tele camera of claim 29, wherein a folding angle of the optical path folding element is in the range 91° to 95°.

64. The folded Tele camera of claim 29, wherein the second lens group comprises at least six lens elements.

65. The folded Tele camera of claim 64, wherein at least three lens elements of the second lens group each include an aspheric surface.

66. The folded Tele camera of claim 65, wherein every refractive surface of each lens elements is a Q-type 1 surface.

67. The folded Tele camera of claim 64, wherein at least the ultimate lens element in the second lens group has a refractive index larger or equal to 1.65 and an Abbe number smaller or equal to 20.

68. A mobile device including the folded Tele camera of any of the claims 1-67.

69. The mobile device of claim 68, the mobile device being a smartphone.

70. The mobile device of claim 68, the mobile device being a tablet.

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