[GarethC7]

Believe it or not, this is all the same topic!

First off, my understanding is that the 1.4X TC is infinitely better than the 2x TC?

Secondly, I have an occasional need/want for a long lens, 400mm+, longer the better, 600mm or more would be great but then we start getting into some marriage threatening prices. I don't need AF so was looking outside the Pentax range but can't find an exhaustive list of what lens mounts that I can use on the 645Z. Can anybody help on what I can use, I have got as far as Bronica, Hassy V and maybe Nikon Ai.

I don't necessarily need stellar image quality but by the same token I don't want soup in the corners and presumably there's a trade off between price and image quality, I guess my real challenge once I've found a list of lenses that will fit with an adapter will be to find that sweet spot where image quality and price balance out for me.

I'd even entertain a shorter lens and a TC to build it up but what are the implications of TC, adapter and lens, that strikes me as an awful lot of hardware.

[bull drinkwater]

Believe it or not, this is all the same topic!

First off, my understanding is that the 1.4X TC is infinitely better than the 2x TC?

Secondly, I have an occasional need/want for a long lens, 400mm+, longer the better, 600mm or more would be great but then we start getting into some marriage threatening prices. I don't need AF so was looking outside the Pentax range but can't find an exhaustive list of what lens mounts that I can use on the 645Z. Can anybody help on what I can use, I have got as far as Bronica, Hassy V and maybe Nikon Ai.

I don't necessarily need stellar image quality but by the same token I don't want soup in the corners and presumably there's a trade off between price and image quality, I guess my real challenge once I've found a list of lenses that will fit with an adapter will be to find that sweet spot where image quality and price balance out for me.

I'd even entertain a shorter lens and a TC to build it up but what are the implications of TC, adapter and lens, that strikes me as an awful lot of hardware.

I must assume you are talking medium format cameras. I am shooting the 645D and have extensive experience with the 1.4 and 2.0 tc's. . with my 200mm,400mm, and 6x7 300mm's I am getting good results with both tc's, I am even getting good results when I stack the two together. a monopod, a tripod, and even a lens support are a godsend. I also try to double the focal length. I.E. if I am using 600mm I shoot at 1/1200 sec.bb

[desertscape]

Low dispersion (ED) glass will cost quite a bit, so one alternative is the 400 Takumar for the 6x7. Even though it uses conventional glass, it is very well corrected. It is an outer bay mount, so the adapter to fit on your Z will have to have the outer bay tabs. Also, the diaphragm is manual, so stop down metering is necessary. The newer gray TCs work well on this lens. If you can afford the 300 EDIF, that is a possibility because the price has been dropping lately. The 1.4X TC shows no image degradation; the 2X only slight. If you are considering the 600mm Takumar, see my lens test here in Pentax Forums.

[GarethC7]

sorry yes, for a 645Z. I'll check out that review, thanks.