Focal Reducer Optics for Same-Mount Infinity Focus
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Solution Overview
Problem
Existing lens adapters with focal reducers prevent alignment of the image plane of a lens with the image plane of the camera when used with lenses and cameras having the same type of lens mount, leading to misalignment and inability to achieve infinity focus.
Innovation Solution
A focal reducer system that includes a field lens and a relay and reducing lens, which translate the image plane of the lens along the optical axis to align it with the camera's image plane, allowing lenses and cameras with the same mount type to be used together by leveraging optics to correct misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a focal reducer is integrated into a lens adapter, then the field of view is widened and lens speed is increased, but the image plane of the lens cannot align with the image plane of the camera when using lenses and cameras with the same mount type
Solution Approach 1:
A field lens is introduced as an intermediary optical element between the adapter optics and the camera lens. This field lens is positioned at the image plane of the camera lens and works in conjunction with the adapter optics to relay and reduce the image, enabling proper image plane alignment while maintaining the focal reduction function. The field lens acts as a mediator that resolves the conflict between achieving image plane alignment and providing focal reduction.
2Length of moving object
If the focal reducer is positioned close to the lens to minimize adapter length, then the adapter remains compact, but the image plane alignment becomes impossible for same-mount-type lenses and cameras
Solution Approach 1:
The field lens serves as an intermediary that enables the system to achieve both compact adapter length and compatibility with same-mount-type lenses and cameras. By positioning the field lens at the camera lens image plane and using it in combination with the adapter optics, the system can maintain a compact form factor while properly aligning the image planes through the relay and reduction process.
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 the use of lenses and cameras with the same type of lens mount by aligning their image planes, providing a wider field of view and increased lens speed for sharper images, and allowing compatibility with different camera systems.
Implementation Method 1
A focal reducer system that includes a field lens and a relay and reducing lens, which translate the image plane of the lens along the optical axis to align it with the camera's image plane
Data Source
AI summary
A focal reducer for use with a camera and a primary lens moves the image formed by the primary lens farther back within the lens/reducer/camera assembly so that the image of an object within the field of view is formed at the image plane of the camera. Relaying the image from the image plane of the primary lens to the image plane of the camera enables the primary lens and the camera, which have the same type of mount, to be used with a focal reducer. Previously, a primary lens and a camera having the same type of mount could not be used with a focal reducer, because the focal reducer interposed between the primary lens and the camera caused the image plane of the primary lens to be located in front of the image plane of the camera, making it impossible for the lens/reducer/camera assembly to achieve infinity focus.