Underwater Conversion Lens for Macro Wide Angle Switching
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Solution Overview
Problem
Conventional underwater photography systems suffer from reduced optical performance due to unaccounted optical properties of water, leading to chromatic aberrations, loss of sharpness, and distortion, limiting the ability to capture close-up images of small subjects without scaring them away or obstructing views with curved distorted image fields.
Innovation Solution
A conversion lens system comprising a bayonet connection of individual lenses within separate waterproof housings, allowing for interchangeable macro and wide-angle perspectives, designed to account for the refractive index of water, enabling flexible lens configurations for underwater photography and cinematography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional land macro lens is used in a waterproof flat lens port, then magnification of small subjects can be achieved, but optical performance deteriorates due to chromatic aberrations and loss of sharpness from field curvature distortion
Solution Approach 1:
The patent applies parameter changes by designing lenses with specific refractive indices and curvatures optimized for underwater conditions. The objective lens has a refractive index of 1.5-1.7 and the relay lens has a refractive index of 1.4-1.6, with carefully controlled curvature radii to compensate for water's refractive index and eliminate field curvature distortion while maintaining magnification capability
Solution Approach 2:
The patent uses composite optical systems combining multiple lens elements with different refractive indices. The objective lens comprises multiple elements including aspherical surfaces, and the relay lens includes elements with specific refractive indices to correct chromatic aberrations and maintain sharpness across the image field when used underwater
2Measurement precision
If a long focal length macro lens is used to achieve life size or greater magnification, then the angle of view is limited to 10-15 degrees, but the scene coverage is reduced
Solution Approach 1:
The patent segments the optical system into two separate interchangeable components: an objective lens for magnification and a relay lens for angle of view control. This allows independent optimization of each lens - the objective lens provides life-size magnification while the relay lens can be selected to provide either narrow-angle or wide-angle coverage, eliminating the trade-off between magnification and field of view
3Measurement precision
If the camera must be positioned extremely close to capture small subjects in macro photography, then the subjects may be scared away or obstructed by the underwater environment
Solution Approach 1:
The patent extends the optical path length in the longitudinal dimension by using a relay lens system with multiple elements and air gaps. This allows the physical distance between the objective lens and camera sensor to be increased while maintaining the optical equivalence of close-focus macro photography, enabling photographers to capture detailed images from a safer distance
4Area of moving object
If a conventional dome port with land wide angle lens is used, then wide angle perspective can be achieved, but image quality deteriorates due to curved distorted image fields and corner blurring
Solution Approach 1:
The patent applies parameter changes by designing the relay lens with specific curvature radii and refractive indices optimized for flat ports. The relay lens includes elements with carefully controlled curvature (e.g., R1=50mm, R2=-30mm) and refractive indices (1.4-1.6) that compensate for the flat port interface, eliminating corner blurring and distortion while maintaining wide-angle coverage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables flexible and creative underwater photography by allowing lens configurations to be changed underwater, reducing disturbance to subjects and improving image quality by minimizing distortion and maintaining sharpness across different perspectives.
Implementation Method 1
the refractive index of water has been taken into account in the design of the conversion lens
Data Source
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AI summary
A conversion lens (1) for underwater photography or cinematography able to change from macro to wide angle photographic perspectives and consists of a sequential assembly of optical lens elements. This conversion lens comprises an objective lens (2), a relay lens (4) and a focusing unit (6) which are positioned on an optical axis and are interrelated in their optical performance to one another. The objective lens is to form an intermediate image (reversed and inverted) from wide angle perspective to half the size of the sensor in the camera, this intermediate image is then transmitted through the relay lens and the focusing unit which projects the image through a macro lens into the sensor of a camera. The three parts can be disassembled and reassembled underwater, all three separate parts are waterproof and therefore the optical performance of water is taken into consideration in the optical system of the invention. The length of this lens can be extended or reduced, and the three individual parts can be changed according to personal preferences. This provides a flexible underwater optical system that can easily be changed in water between macro and wide angle perspectives, depending on the photographer's needs.