Hi -- Refreshing to discuss manual-focus film gear in the midst of all this tumult about the new dSLRs. :-) And here I am responding despite not having definitive answers... I have a 300mm for 6x7 and a K-mount adaptor, but have not yet tried these on a 35mm Pentax. I suspect the 300mm for 645 would be optically similar, and mine is very good. If your use of this long focal length would be only occasional, it hardly makes sense to spend money for a good lens. So your price is definitely right! I paid $141 for the used adaptor, which was about half the cost of my used 300mm. I figured my use of any 300 on 35mm would be rare, so the cost of the adaptor was reasonable I thought to make my existing 6x7 lenses usable on both platforms. A 654->K adaptor might make similar sense to you, depending on prices for the adaptor vs a decent K-mount 300mm lens.
On the Sigma 28mm, I understand their premium lens line is excellent, yet I don't know where that particular lens falls, quality-wise. I've only rarely bought non-Pentax lenses for my Pentaxes. I did long ago have a Vivitar f/3.0 28mm that was ok, but I replaced it with a Takumar as soon as I could afford to. I guess you'll need to put that Sigma through its paces in a variety of light... Check for backlight flare, out-of-focus character wide open, close-ups, contrasty light, etc. I'm now doing that with a Kiron 28mm that came with a Pentax K2 body from eBay... Ironically, the K2 was badly gummed up, needing CLA, while the third-party lens is in fine shape. :-) Good luck with your new goodies! Doug Miles On 09/13/06 18:39, "Ivan Shukster" <[EMAIL PROTECTED]> wrote: > How good are 645 lenses on a SLR or DSLR. I may have access to a 300mm > lens and is it worth buying an adapter for just one lens? > > I will be testing the 28mm this weekend. It seems like ages since I have > used any of my Pentaxs and I hope it is a while before I even think about a > new one -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
