Canon Patent Application: Improved DSLR Viewfinder
Several factors come up with viewfinders; we want one where the aberrations are low, the magnification is high and the eyepoint is large enough for those that wear glasses.
In this patent application Canon appears to be trying to improve on aberrations and magnification while maintaining a long eyepoint.
They also mention in this document that the standard viewfinder has a 65mm focal length, and a .8x magnification with a 50mm lens. Assuming it's a straight ratio, it would appear that Canon is looking at doing a 1.00x magnification viewfinder in this patent application.
However, patent documents described above In the prior art disclosed in No. 1, the focal length of the eyepiece is about 65 mm, and the finder magnification is about 0.8 or less when the standard lens with a focal length of 50 mm is mounted as a photographing lens. Therefore, in a camera using a so-called APS-C size sensor in which the size of the image circle is smaller than a 35 mm film, the finder image becomes smaller than the conventional silver halide film camera. Further, in the prior art disclosed in Patent Document 2, although the finder magnification is as high as about 1 time, it is difficult to sufficiently correct axial chromatic aberration and lateral chromatic aberration.
Therefore, an object of the present invention, while increasing the magnification while maintaining high optical performance, is to provide a finder optical system capable of ensuring long eye point.
Could this be a new viewfinder that will appear on the 90D? It's entirely possible. If the 90D is to take the place of both the 80D and the 7D Mark II, one of the features must be an improved viewfinder.
Japan Patent Application 2019-078959
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