Why no 40mm pancake (or similar)?

Started Feb 9, 2018 | Questions thread
Astrotripper Veteran Member • Posts: 6,827
Crazy idea - 40mm f/2.8, about 30-35mm in length
3

Pentax smc DA 40 mm f/2.8 XS. Specs say 9mm, but no idea if that includes the protruding mount part. Worst case, with an adapter that will be ~35 mm long, so about 10mm longer than Panasonic 20mm and 10mm shorter than Oly 45mm

Interestingly, focal reducers are slimmer than regular adapters. Metabones SpeedBooster (to EF) is only ~18mm, while LensTurbo II ~22mm. Slap that on, add a Pentax K to EF adapter and you have 50mm f/1.7 lens that's about 40mm long. But that's getting close to Oly 45mm.

Note, this is just crazy talk, I have no idea if any of that would work (Pentax lenses I think have a protruding aperture lever that might interfere with the focal reducers, for example).

 Astrotripper's gear list:Astrotripper's gear list
Sigma DP2 Merrill Olympus PEN E-PL1 Olympus OM-D E-M10 Panasonic Lumix DMC-GM5 Olympus E-M1 II +17 more
Post (hide subjects) Posted by
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow