OK, I did the obvious thing and put that 500/4.5 takumar on my M42->NikonF optical converter and mounted it on my D1H and went out shooting youth football. I have a few observations, and a question.
1) Sharpness is really quite good, even at the edges. Within my limited experience with both lenses I'd suggest that the 500/4.5 is giving a better optical performance than my 300/4 takumar. Both lenses appear to be equal to the "K" versions, but without SMC. 2) Contrast isn't great, as would be expected without SMC. Color fringing is visible under adverse conditions, as would be expected without APO glass. Color rendition on a Nikon digital is a little odd, which may be the glass and coating. Digital is not going to handle old glass and coatings well, I suspect. Also, Nikon coatings may be inferior to SMC, but they have a very good reputation for delivering consistent color rendition across the range of Nikon lenses, which may mean that the D1H is essentially expecting a "Nikon" color rendition. 3) The lens CAN be used for action, although the location of the helicoid behind the tripod mount and the lack of internal focusing make it a lot harder to manage than a modern design. Lack of auto diaphragm sure encourages shooting at or near open aperture! Of course we're talking about a 40-year old design here, and one that I paid less than 20% of the going price of a used 500/4 EDIF for. That, and it's impossible to fit a 500/4P Nikkor to my Spotmatics. The question is, why does it work so well on the optical M42->F adapter? Both it and the 200/3.5 takumar (which appears to have an almost identical 4/4 telephoto optical formulation) are quite sharp, even at the edges, on the adapter. By contrast, my 28/3.5 takumar shows noticeable degradation of sharpness on the adapter, especially at the edges, on film. Without the adapter, it's competitive with almost any 28mm ever made, at least on film. My 20/4.5 takumar is unusably soft and otherwise nasty-looking even at the center on the D1H and adapter. Of course the 28 is a more complicated optical design (7/7) and is a retrofocus design. The 20 is yet more complicated optically (11/10) and is essentially a double retrofocus design, plus it isn't the best lens Pentax has ever made even without the adapter--some noticeable distortion and loss of sharpness towards the edges. Is it the inherant complexity of the wides that makes them suffer so much on the adapter, or the inherant simplicity of the teles that keeps them from suffering? Perhaps the optical tricks retrofocus wide-angles have to play are to blame instead, or the distortion and other aberations of early wide-angles? I note that most pros only use 1.4x teleconverters on long telephotos, which presumably have the same virtue of not having to bend the light as oddly as zooms and wides. I'm really curious how the converter and D1H fare with some of the classic Pentax 5-element mid-teles, such as the 105/2.8 and 150/4. Perhaps if Pentax can stay in the race long enough they'll put out a DSLR that will win me over. If not, I'll probably have to suck it up and buy a Canon, because the optical adapter thing with Nikons is a pain. DJE
