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p.2 #6 · p.2 #6 · Best Voigtlander M-mount lenses for Leica and Sony sensors | |
retrofocus wrote:
I should have added into the exemption of poor performing wider lenses ASPH f/2 lenses - you are absolutely right, and I have described the same with the Leica 35/2 ASPH in the past in this forum. On the other hand, the Leica 35/1.4 ASPH does very well with the Sony sensor stack - which comes back to my point with the larger rear lens element.
Btw, I find the often in this forum used term "exit pupil" very confusing. Not sure if the majority understands what exactly it means in this context. Is it the same as what I was saying that the angle of refraction is steeper towards the border of the sensor frame with smaller rear lens elements? ...Show more →
The exit pupil is the image of the aperture further down the optical path. The distance of this image of the aperture (i.e., the exit pupil) can be measured. So, it isn't the same as the angle of incidence, but the distance of the exit pupil and it size (which is determined by the aperture at which the lens is set) does determine the angle of incidence. So, shorter exit pupils mean a steeper angle of incidence at any given aperture. That may all sound confusing, but it really is pretty simple. On digital sensors you want the rays of light coming together further from the sensors (i.e., a longer exit pupil) so the angle the rays hit the sensor are shallower angles. Steep angles cause problems especially with thick cover glass and especially at the edges. Making lenses that bring the rays of light together further from the sensor combats this effect by creating shallower angles.
So it is basically the same as what you are discussing but it is the measurement of something different that results in what you are discussing, if that make sense.
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