Upload & Sell: On
Can anyone explain Pentax odd focal length on their lenses?
15mm, 21mm, 31mm, 43mm, 77mm
Even the full frame equivalent is odd.
I've always been intrigued with the Pentax SLRs. The limited lenses get rave reviews, but are they all screw drive?
If I can be bothered Googling it I'm sure I could eventually find the full explanation somewhere. However I clipped this to the Together app I use (like Evernote) a few years ago :
The abstract from Jun Hirakawa's technical report...
Abstract; This paper introduces features the titled lenses on the following items: 1) Standard and middle range telephoto lenses for a 35 mm single-lens reflex cameras sold by Pentax, 2) design concept and performance; unique expression with high quality picture, 3) exterior; machined aluminum body to provide high grade sense, 4) focal length; 43 mm (diagonal length of 35 mm size film) and 77 mm (lucky number among 70-80 mm), respectively, 5) both AF and MF operation possible, 6) helicoid screw at focus part provides torque feeling, 7) realization of smooth AF operation by a little reduced gear ratio of drive unit and 8) lens aberration compensation; priority to practical photographs expression than numerical evaluation.
In other words Hirakawa didn't give a crap about MTF... he just wanted good pictures.
BTW the 3 amigos have been described by the Editor of one of the USA's top photography magazines (I've clipped this somewhere as well) as 3 of the best lenses ever made (I think the 31 was #1) - and they truly do give simply amazing rendering, clarity, contrast and excellent sharpness. They have pixie dust sprinkled liberally upon their tiny (well, small) bodies.