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03-02-2018, 10:00 AM   #16
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QuoteOriginally posted by Fogel70 Quote
Then why do you not explain how to design fast pancake lenses with help of an protruding rear of the lens.


Are you saying that lenses like DA21 is not possible?


---------- Post added 02-28-18 at 01:28 AM ----------

So what is the relation between exit pupil position and vignetting/color shifts?
Compare this DA21 to Canon EF-M 22/2 STM: more than a stop faster, cheaper, and 105 grams vs. 150 grams while the EF-M lens has AF motor and DA21 doesn't. The lens barrel in the EF-M is small enough so it could poke inside of K-mount.

03-02-2018, 12:35 PM   #17
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QuoteOriginally posted by alliumnsk Quote
Compare this DA21 to Canon EF-M 22/2 STM: more than a stop faster, cheaper, and 105 grams vs. 150 grams while the EF-M lens has AF motor and DA21 doesn't. The lens barrel in the EF-M is small enough so it could poke inside of K-mount.
That is the problem. As with an optical design like EF-M 22 mm the front lens would have to be behind the mount on K-mount camera. The rear lens barrel on EF-M 22 is quite large and looks to be more than 24mm in diameter which is the height of the mirror box. Where to fit motor and electronics on a lens like this?

It may be possible if making a non backward compatible version of K-mount where power zoom contacts and mechanical aperture lever is removed from the camera, and new AF contact is added on the mount.

Last edited by Fogel70; 03-02-2018 at 12:43 PM.
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