genji wrote:
Lloyd Chambers published on his blog (not behind the paywall) a post titled Ray Angle From Lens Exit Pupil (Table of Ray Angles for Zeiss ZM Lenses) which lists the chief ray angles for all the Zeiss ZM lenses. The value for the Distagon ZM 35/1.4 is 32.5 degrees. Would I be correct in assuming that one could use the ray angle and frame size to calculate the exit pupil distance?
Thank you for the comment.
Exit pupil distance can be estimated from the chief ray angle.
arctan( 34.0 / 21.64 ) = 32.5.
*Note 21.64 is 1/2 of 35mm format diagonal size.
So I got Exit pupil distance = 34.0mm.
Hmm this is so different from last estimated value 27.86mm(Exit pupil diameter 19.9mm estimated from Nanh\'s photo * fno 1.4), but I don\'t know why.
With the new condition: Exit Pupil Distance - Focal length = -1.0mm, I run again the simulation.
In this case also, simple PCX doesn\'t work well at f1.4. So I used meniscus.
Oct 19, 2016 at 07:12 AM
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genji wrote:
Lloyd Chambers published on his blog (not behind the paywall) a post titled Ray Angle From Lens Exit Pupil (Table of Ray Angles for Zeiss ZM Lenses) which lists the chief ray angles for all the Zeiss ZM lenses. The value for the Distagon ZM 35/1.4 is 32.5 degrees. Would I be correct in assuming that one could use the ray angle and frame size to calculate the exit pupil distance?
Thank you for the comment.
Exit pupil distance can be estimated from the chief ray angle.
arctan( 34.0 / 21.64 ) = 32.5.
*Note 21.64 is 1/2 of 35mm format diagonal size.
So I got Exit pupil distance = 34.0mm.
Hmm this is so different from last estimated value 27.86mm(Exit pupil diameter 19.9mm estimated from Nanh\'s photo * fno 1.4), but I don\'t know why.
With the new condition: Exit Pupil Distance - Focal length = -1.0mm, I run again the simulation.
In this case also, simple PCX doesn\'t work well at f1.4. So I used meniscus.
