Wonderful design...showing a great sense of imagination!
Dave Oddie: Pentax seem to have forgotten the K-5 is an aps-c camera when designing the 40mm lens.
On a full frame camera that focal length is great (I owned an Zuiko 40mm F2 in film days) but on aps-c with a f.o.v equal to 60mm I can't think of a more useless specification for a prime lens.
Pentax are not the only one to do this. Sony brought out a 50mm "portrait" lens when that is really too short to be a classic portrait lens with a f.o.v of a 75mm.
They are both far too conservative and seem to think they should stick to focal lengths that are really for full frame rather than develop specifically for aps-c. A 28mm prime which is approx 42mm f.o.v would have been much better.
I doubt if Pentax forgot anything. They designed exactly the lens they wished to build and sell. It really comes down to a matter of preference by the photographer.
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