Adapting Pentax 645 / 67 leaf shutter lenses

[anyone]

Hi,

here are a lot of Pentax 645 / 67 shooters. I do have a specific question on leaf shutter lenses. Is there a possibility to fire (and cock) the leaf shutter without actually having the lens mounted to a P67 body? It seems that the lenses can be cocked on the lens itself and the 90mm seems to have also a cable release socket. On other lenses I did not see this. Can someone confirm this?

I'm thinking to adapt these lenses, but would need the shutter as my digital back does not have an ES. A related question is of course: is the IQ worth it? I like to shift quite a bit, so the larger image circle of the lenses would be most welcome.

Thank you!

 

[rdeloe]

Can't help you with the specific leaf shutter question. However, I have used Pentax 67 lenses (and do use Pentax 645) for shifting on a Fuji GFX 50R. Whether or not the image quality is good enough for you is a personal decision. I can say that most of the Pentax 67 and 645 lenses I've tried or use are excellent and allow for useful amounts of shift on my GFX 50R. Among P67 lenses, the 55mm f/4 (latest edition) is especially good. I've only compared one Fuji GF lens directly to the corresponding focal length in Pentax 645 (the GF 63mm f/2.8 to the 63mm position on my SMC Pentax-A 645 45-85mm f/4.5). At the apertures I normally use (f/8 through f/16) the Pentax holds its own easily against the Fuji.

 

[tsjanik]

I have the 645 135mm LS. It's very sharp and works well with the 645D/Z. However, the shutter is fired when the camera body pushes the aperture tab in the rear of the lens. This works fine with the Pentax cameras or any adapter which would allow full aperture viewing and then closes the aperture during exposure. I have a Fotodiox "dumb" adapter for GFX and the LS mode is unusable since the adapter stops down the lens and thus fires the shutter. The 67 90mm would appear to be useable since it has a cable socket on the lens, but it's an old design and gets mixed reviews:
https://www.pentaxforums.com/lensreviews/Pentax-SMC-Takumar-6x7-90mm-F2.8-Leaf-Shutter.html

 

[itsdoable]

I can't comment on the IQ for digital, I only shot them on film. I found the 90mm and 165mm f/2.8 a little better than the LS versions, but not something you would notice unless peeping.

It has been many years since I owned both systems and shot with them, I had the factory Pentax 67-645 adapter which gave full aperture coupling so you could shoot the 67 lenses on the 645 with aperture priority AE. And I do remember using both the 90LS and 165LS on the 645 with LS sync'ed flash outdoors. I recall setting the 645 FP shutter to 1/8th.

If you can find an adapter that allows you to open and close the aperture, or modify one to do this, then you would be able to trip any of the LS lenses independently.

 

[anyone]

Thanks for your answers! Not sure if it's encouraging to go that route The reviews of the 90mm didn't sound great, I suppose a Grandagon 6.8/90mm could be just as good (or better) with larger coverage, which is of course not really needed for the digital back.

I possibly need to add that (currently) I am limited to leaf shutter lenses as my digital back does not have any ES - therefore my interest to trigger the shutter.

Does anyone know if such an adapter exists that would make it possible to trigger the shutter? In the end, it would need to be somehow like with a Copal shutter for a large format lens: a thread mount for a cable release, and the cable release presses down a lever that is triggering the aperture and thus fires the shutter.