[Abbazz]

I was thinking that too but it looks like the image circle is 21.64mm so that's not going to cover more than 35mm.

If the full image circle diameter was 21.64mm, then It wouldn't even cover APS-C (diagonal is 26.8mm)... I think 21.64mm is the radius fo the image circle, which corresponds to the "full frame" 35mm format. Unfortunately, the actual lens derived from this model has never reached production, maybe because Pentax was focusing on APS-C lenses at the time.

Cheers!

Abbazz

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Last edited by Abbazz; 01-26-2022 at 09:43 PM. Reason: Edited for content.

[Pond-Curtis]

If the full image circle diameter was 21.64mm, then It wouldn't even cover APS-C (diagonal is 26.8mm)... I think 21.64mm is the radius fo the image circle, which corresponds to the "full frame" 35mm format. Unfortunately, the actual lens derived from this model has never reached production, maybe because Pentax was focusing on APS-C lenses at the time.

Cheers!

Abbazz

My bad, I meant 21.64mm radius. It's a very common radius for 35mm.