Originally posted by photodesignch honestly though.. you could've gotten 28mm F2.0 Contax MMJ version and swap the mount to PK still comes cheaper. And it's identical lens.
Yes, optically identical. Not functionally.
If you use it wide open, or stopped down a couple of clicks, it would be practical to use in AV, but IMHO it would seriously limit its usefulness.
The green button procedure is a pain in a place where the sun rarely shines... but you get focusing at f/2 even if you shoot at f/11. Great in low light, and for accurate focusing on close range subjects. Which is the kind of photography I usually do.
The main asset of this lens is the very good IQ over the entire focus range.
I have leitaxed/T-mount/preset lenses, and I found that a preset diaphragm makes everything faster, more practical and more ergonomic.
Leitaxed lenses aren't so ergonomic, unfortunately. If I had to choose a Zeiss lens for conversion, I'd go 25mm or lower, which would be more forgiving if focusing is inaccurate.
I bought my Pentax/Zeiss 2/28mm long long time ago. Someone bought the new tiny 2/28mm (we were in full OM/Zuiko craze, small was very fashionable!) and returned the oddly shaped predecessor. I did the opposite, returning the M 3.5/28mm, and adding some cash, I could lay my hands on that strange, lanky wide angle
I never looked back, and I guess it would stay with me for very very long...
I never understood why some people were ready to pay so much to use it on APS-C, but now the K-1 has changed the scenario.
Oddly enough, I've seen the price go down a little. I'll never understand the dynamics of the market!
Cheers
Paolo