p.1 #1 · Pentax or Mamiya 645 to adapt to GFX; what about Mamiya RB67 lenses?
I currently use my GFX100s mostly for 1x1 and panoramic shots and mostly with the 35-70mm lens. I also have the Fuji 50mm and the 63mm.
Bought the Canon EF 70-200mm f/2.8 III before I left the US to use both as a long lens on the GFX and on my Canon R5. Thing is I use the R5 mostly for model shoots with just the RF 50mm f/1.2 and I've only used the 70-200mm with the Fuji on one trip. (I generally take my MFT gear and the Fuji on landscape-oriented trips and the Canon gear stays home).
So, I'm thinking of selling the Canon lens and using a longish (200mm and up) Mamiya or Pentax 645 with the GFX. I don't want to buy too many adapters, so I'm curious which brand offers the more interesting longer lenses, Pentax or Mamiya? And what are the greatest lenses, both for landscape and portraits within those brands?
I also have the vaunted 127mm f/3.8 lens for the Mamiya RB67 that I want to try on my Fuji, but I understand it can be a bit of a hassle adapting those lenses. Anyone with experience?
p.1 #2 · Pentax or Mamiya 645 to adapt to GFX; what about Mamiya RB67 lenses?
I don't have experience adapting the Mamiya RB67. But I do routinely use the Contax 645 140/2.8 with a Fringer and love that lens. Also have the Mutar 1.4X for it and the 210/4 which is also a great lens. But these are auto focus lenses and like most AF lenses, they aren't that much fun to manual focus (with exception of the MF Contax 120/4 macro which is a MF dream to use).
p.1 #3 · Pentax or Mamiya 645 to adapt to GFX; what about Mamiya RB67 lenses?
Fringer sells a P645-GFX AF adapter that works pretty well, so if AF matters, that might be a consideration.
Pentax has a decent and fairly small/light 150-300 5.6, a rather large 400mm 5.6 that AF, and a very good AF 150mm 2.8. The MF 150mm 3.5 is small and sharp as well. Generally, the P645 AF and MF 200mm f/4 aren't terribly well regarded.
p.1 #4 · Pentax or Mamiya 645 to adapt to GFX; what about Mamiya RB67 lenses?
I have the Mamiya 210/4 for the 645 system and it's a very nice lens. However, since I also have the GF 100-200 I never use the Mamiya. I do use the Mamiya 150/3.5 though that is much smaller, but not as good. The 210 is awkwardly long with the adapter and quite front heavy. But it's a dirt cheap lens, so I still recommend it.
There is also a 300/5.6 that is nice and not much larger IIRC. Also dirt cheap. Both that and the 210 have veeeery long MFD. I suppose that is common with old telephoto lenses with unit focusing.
From what I've seen, Pentax 645 lenses might perform slightly "better", but they also often give a lot of lateral CA while the Mamiyas don't.
