Last Thanksgiving, I had an opportunity to acquire a Contax Carl Zeiss 28mm/f2.8 Distagon *T lens (a C/Y mount) at a pretty good price, in mint condition. I purchased the K mount conversion kit from Leitax (in Spain) - and it was caught in US Customs for "awhile" during the holidays. [David at Leitax has tracking numbers on everything he sends - wonderful service]. It finally arrived, and then I sent it off to Eric to be modified. I guess I could have done it myself, but I considered it too nice a lens for me to botch the job on. Eric did a great job, and now I have it back.
Normally, it would not be a real fair comparison, but I pulled out the 31 Ltd and shot several comparison images. The difference in focal length is much more noticeable than I expected. I did a set of distance shots and then a set of close in shots, into the center of a spider cactus plant.
I have some back focusing on the 28 @ f2.8. I do have to say the 31 is absolutely perfect - and comparing anything with it, you see the differences immediately. I found and printed the target along with the focus adjustment instruction page from the K20 manual. This afternoon in the kitchen under the skylight (natural sunlight), I set everything up and it looks like I have about 5mm of backfocus - that is, when I get everything in focus. I do have to say, that this is more difficult than an eye examination - I really miss my split prism from my old Spotmatic. [Note - I think that a Katzeye is in my future.]
I have a couple of questions - since I have never had to apply a focus adjustment before.
- Since this is a manual lens (K lens equivalent), the focus adjustment I specify to this one lens, will it be applied to all manual lenses or just to all 28mm manual lenses? (I also have a K 28/3.5 Shift and an A50/1.7.)
- Is it any better to use the Pentax Remote Assistant Tether utility in this effort to get (and verify) the right focus? Or would Live View be better?
- I am finding that it is pretty difficult not to move, bump, jiggle or jostle anything - so as to ensure the ability to get repetitive results.
My intent for the lens is low ambient light landscapes, and stitching panos with it. Thus, I am going to have some latitude with it in terms of focusing in actual use (to some degree). Also, I was very interested in seeing how one of these lenses (Zeiss) compared to the 31 in terms of sharpness, color, contrast, shadows and overall IQ. I haven't come to any conclusions as of yet - other than its a very nice lens - substantially smaller than the 31, with the same build quality - all metal and glass.