Why no 40mm pancake (or similar)?

Started Feb 9, 2018 | Questions thread
mkaresh Regular Member • Posts: 140
Re: Conclusion: I seem to be the only one ;-)
1

See my comment below. Whatever was done to enable the Pentax 70mm should enable a 40mm, 45mm tops m43 pancake.

The short version:

The key thing to realize: focal length is measured to the sensor. The Pentax lens is for an SLR, with a mirror and much thicker camera body. With a thicker body the lens can be shorter for a given focal length, as more of that focal length is occurring within the body rather than within the lens.

I do wonder what is given up by having fewer elements within the lens, 6 in the Pentax vs. 9 in the Olympus 45mm and 14 in the 45mm Pro. For a sense of what can be fit within a collapsible pancake, the Panasonic 12-32 does have 8 elements, so nearly as many as the Oly 45mm.

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