View Full Version : Attaching a Mamiya RZ lens to a Chamonix 45n-1?

5-Mar-2010, 01:45
Hi, I realize that this question might be frowned upon by many large format photographers but was wondering if anyone knew if it was possible to attach a Mamiya RZ 110mm lens to a Chamonix 45n-1? I am looking to go traveling with this setup and often can't quite justify shooting portraits on large format film (purely on cost alone). This lens has a leaf shutter and the dimensions on the website for its length and width are 62mm x 97.2mm. I have measured the width of the front of the Chamonix and it is roughly around 97.2mm. It might mean shaving off some of the wood and cutting a new hole where the lens goes but apart from that, can anyone see any other reason why this wouldn't work? If not that lens, can anyone think of a fast, standard 67 lens that might be comparable? I have seen 100mm f2.8 Xenotars that are already mounted on lens boards that might be suitable. I think they have shutters in them.... Any thoughts? Ok, thanks for all your help. Best Regards Josh

5-Mar-2010, 02:43
I have a sinar board with RB67 mount (from a extension ring) attached to it - as the mount does not extend into the camera, and any protruding rear elements are quite narrow, that should be feasible even with the most diminuitive lens boards. However it is impossible to do the same with RZ lenses (at any rate not unless you use a FP or BTL shutter along with it), as they have an electronic shutter controlled from the body!

The Mamiya Press f/2.8 100mm would probably be the best option for a affordable fast lens with 6x7 or bigger coverage, and as it is shutter mounted, the lens/shutter assembly can even be taken out of the barrel and rebuilt onto a lens board. Just like the 110mm, it is nowhere near close to covering 4x5, though - they don't even cover 3x4 (Polaroid) at portrait distance!


6-Mar-2010, 01:34
The RZ lenses have electronic shutters controlled by the camera body, which means you will need some electronics to control the lens if you intend to use its shutter. If you've got some other shutter to put behind it, keep in mind that the 110/2.8 exit pupil is about 50mm so your shutter would need to be at least that big - you can't install your own shutter in the middle.

I suspect an RB lens (no electronics required) would be a much simpler approach. That means you can't get the 110 though.

Edit: An RZ67 body and back costs about the same as the 110/2.8. If you're dead-set on using small-coverage lenses like the 110/2.8, presumably to save money, the easiest approach is to buy the body it was meant to be mounted to.

8-Mar-2010, 04:08
Hi, Thanks so much for the responses, much appreciated! Hmmmm, yep, knew there would be a catch of types.. The main reason I am looking at this option is purely based around travelling and the obvious weight concerns, otherwise i would just be looking at using a Mamiya RZ. Is the RB lens I am looking for the current RB67 Pro SD line or am I looking at older RB lenses? So yes, I would miss out on the faster 110 2.8 and the weight is also getting up there ( might as well look at getting a Mamiya 7 with 80mm lens for that weight ). So maybe the Xenotar 100mm 2.8 is an option. Sevo, I didn't quite get the part of your post with regards to the shutter. Can I easily find one with a shutter or is it a barrel lens that I would need to place into a shutter (which can get very expensive I thought ). Would there be a big loss in sharpness shot wide open at 2.8 compared to the RZ 110 2.8? Any other lens out there that might be sharper?

Also, this lens does cover 6 x 7cm right? Any room at all for some movements? Under a google search I see it listed as a 3 1/4 x 2 1/4 lens and also see it listed as a 3 x 2 lens. Any ideas? I also see it has a 105mm 2.8 version.

Ok, thats it for the moment. Thanks again for the responses, much appreciated! Best Regards Josh

8-Mar-2010, 04:20
Just another quick one, I already own a Xenotar 135mm 3.5 and a Xenotar 150mm 2.8. Just wondering what focal lengths they both effectively become when used on my Chamonix with a 6 x 7cm back? I was thinking about a 180mm for the 135mm and a 210 or so for the Xenotar 150mm 2.8. Does that seem close or am I off somewhere? This might be ideal as I would probably already be carrying the lenses around with me. I was ideally looking for a standard lens for the 67 format but this might be close. Ok, thanks so much again. Best Regards Josh.

8-Mar-2010, 04:27
The focal lengths won't chance by being attached to another camera.

12-Mar-2010, 02:19
Sorry, what I mean with the focal lengths is, what does a 5 x 4 lens effectively become with a 6 x 7 back in place? Ie I am sure a "standard" 54 lens (150mm) is more than just slightly longer than normal on 6 x 7 format.... I think I posted a post a bit back and someone gave the answer of needing to multiply the 5 x 4 focal length by 1.7 to get an "equivalent" 6 x 7 rollfilm focal length.. Does this sound right? Best Regards Josh

12-Mar-2010, 03:28
The long side of the exposed area is about 115mm for 4x5 and 68mm on 6x7, so 1.7 would be the right factor. However, "equivalent" maths are not that widely used for formats other than 35mm - the negative equivalent focal length is rather meaningless if you do not live in a world of postcard size prints. In professional applications you'll have to worry about print diagonals and viewing distance instead. And beyond that, people do get into heated debates as to which focal length between 135-180mm is the applicable "normal" for 4x5", and there is not one common opinion regarding 6x7 either (Mamiya offered a choice of 90mm and 127mm on the RB and settled on 110mm for the RZ)...