Roll film back questions (Cambo C2n)

Jimi3 · May 15, 2023

I’m considering picking up a C2n 6x9 back for my Chamonix 4x5 - would save some weight on hikes to use rolls of 120 vs 4x5 film in holders, cut costs for shooting color film and b&w infrared, and generally ease the transition from digital, in which I’m used to shooting a lot of frames. My view camera has pretty extreme movements too, so I should still be able to take advantage of them even with the crop factor.

So, since the Cambo slides in like a film holder, it should work on my Chamonix, correct? Though the spring action on the back doesn’t seem as strong as some other cameras I’ve played with. I’m also wondering about lenses. Right now I only have a 90mm super angulon and 150mm Fujinon, and I’ll definitely want something wider. I was thinking about picking up a 58mm for 4x5 anyway, but if I wanted to go even wider, is it possible to mount a lens that wouldn’t cover 4x5 on a large format lens board?

Dan Fromm · May 15, 2023

Jimi3 said:
is it possible to mount a lens that wouldn’t cover 4x5 on a large format lens board?

Why should a hole in a lens board care what's stuck in it?

MattKing · May 15, 2023

Jimi3 said:
is it possible to mount a lens that wouldn’t cover 4x5 on a large format lens board?

Dan Fromm said:
Why should a hole in a lens board care what's stuck in it?

Perhaps it would be more helpful to answer as follows:
Yes, some lenses designed for smaller formats (2.25" x 3.25"?) may fit on some lens boards that will fit on 4"x5" cameras.
The hole in the lens board is more likely to be matched to a shutter size than a film format.

Jimi3 · May 15, 2023

MattKing said:
Perhaps it would be more helpful to answer as follows:
Yes, some lenses designed for smaller formats (2.25" x 3.25"?) may fit on some lens boards that will fit on 4"x5" cameras.
The hole in the lens board is more likely to be matched to a shutter size than a film format.

Thanks Matt - that is along the lines of the answer I was looking for. I wasn’t sure if medium format/shorter focal length lenses that fit the shutter size holes of large format lens boards would be widely available. It would be nice to have something shorter than 58mm dedicated to 6x9 shots.

MattKing · May 15, 2023

I know there are some adapters out there that permit using lenses designed for the RB67 - including the 50mm - on 4x5 cameras. That lens will most likely cover 6x8, but may not stretch to 6x9.

Jimi3 · May 15, 2023

MattKing said:
I know there are some adapters out there that permit using lenses designed for the RB67 - including the 50mm - on 4x5 cameras. That lens will most likely cover 6x8, but may not stretch to 6x9.

Hmm, I wonder how the shutter is triggered. I’ll do some searches. Perhaps I’d be best off just getting a LF 47mm.

MattKing · May 15, 2023

Jimi3 said:
Hmm, I wonder how the shutter is triggered. I’ll do some searches. Perhaps I’d be best off just getting a LF 47mm.

The shutter release uses the mirror up release on the lens. The adapters control cocking the shutter.

John Wiegerink · May 15, 2023

I bought a couple of blank, 3D printed, lens boards for my Chamonix. I also have a Calumet roll film holder and it slides in mine, but I really haven't used it to shoot with yet. My plan was to used the C2 roll film holder for transparency film and my 100mm Wide-Field Ektar as a normal focal length( a little long, but....) lens and a 75mm Schneider Angulon with plenty of coverage. If that combo works I'll then swap-out the Calumet C2 for a 6X9 Toyo roll holder.

Jimi3 · May 16, 2023

MattKing said:
I know there are some adapters out there that permit using lenses designed for the RB67 - including the 50mm - on 4x5 cameras. That lens will most likely cover 6x8, but may not stretch to 6x9.

Hmm. I haven’t been able to find any real info on adapters. Maybe time to start a separate thread…

Jimi3 · May 16, 2023

John Wiegerink said:
I bought a couple of blank, 3D printed, lens boards for my Chamonix. I also have a Calumet roll film holder and it slides in mine, but I really haven't used it to shoot with yet. My plan was to used the C2 roll film holder for transparency film and my 100mm Wide-Field Ektar as a normal focal length( a little long, but....) lens and a 75mm Schneider Angulon with plenty of coverage. If that combo works I'll then swap-out the Calumet C2 for a 6X9 Toyo roll holder.

Yeah, I just ordered the Cambo 6x9 holder from KEH. I’m questioning whether it will be too heavy for my Chamonix, but hopefully I won’t have to send it back.

abruzzi · May 16, 2023

Jimi3 said:
Hmm. I haven’t been able to find any real info on adapters. Maybe time to start a separate thread…

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I don't know what camera its for, but with a little ingenuity, the mechanical parts could be transplanted to another lens board.

Dan Fromm · May 16, 2023

Jimi3 said:
Thanks Matt - that is along the lines of the answer I was looking for. I wasn’t sure if medium format/shorter focal length lenses that fit the shutter size holes of large format lens boards would be widely available. It would be nice to have something shorter than 58mm dedicated to 6x9 shots.

Well, if that's what you really asked about, please see:

https://1drv.ms/x/s!AggQfcczvHGNgYhYGeQuOzsBIyw8Og?e=uIWOnL A list
of lenses with focal lengths 65 mm and shorter that cover 2x3 (= 6x9). Most
concerned about whether they can be mounted on and focused to infinity on my
2x3 Graphics. Incomplete like all such lists but I don’t think anything significant
is missing.

You want lenses in shutter, and the shutter must have a cable release socket. If it isn't clear, this rules out lenses for, e.g., SLRs and TLRs, that are triggered by the camera body.

MattKing · May 16, 2023

Dan Fromm said:
You want lenses in shutter, and the shutter must have a cable release socket. If it isn't clear, this rules out lenses for, e.g., SLRs and TLRs, that are triggered by the camera body.

Excepting lenses for the RB67, if you can deal with the shutter cocking.

Axelwik · May 16, 2023

Jimi3 said:
...is it possible to mount a lens that wouldn’t cover 4x5 on a large format lens board?

Check the flange distance. Many large format cameras won't be able to focus close enough for such a short lens.

abruzzi · May 16, 2023

The Mamiya Press 50mm ƒ6.3 can be remounted in a Copal #0. It barely covers 6x9 at infinity. I have on in a 110x110 recessed arca board, but it would work fine on a flat board, since the Arca Swiss F-Classic 6x9 will focus just under 50mm with a flat board (I think it will handle Super Angulon 47mm.) I don't know the minimum on your Chamonix, the A-S is very good in that respect..

xkaes · May 18, 2023

MattKing said:
Excepting lenses for the RB67, if you can deal with the shutter cocking.

You can adapt RB67 lenses to a 4x5 (or other) LF-sized cameras, but they are designed for 6x7 coverage, not 6x9. -- as Matt mentioned Plus, they are all very large and heavy -- although prices are pretty reasonable nowadays.

Here's how I adapted my RB 37mm fisheye. Works fine -- because it's a fisheye lens -- once you get used to how the shutter has to work, that Dan and Matt mentioned. That adapter board makes things much easier, but won't change the coverage limitation, the weight, or the size. The 37mm weighs about three pounds, for example.

http://www.subclub.org/fujinon/gonefishin.pdf

If you don't mind a little cropping, then you are all set, but in that case, if you are OK with cropping just use regular, in-Copal, 4x5 lenses. Better yet, since the 6x9 format gives you a narrower picture angle, just use a longer lens. If you want to keep the extra-wide picture angle, there are plenty of 6x7 lenses to choose from -- but a 50mm on 6x7/6x9 is very different from a 50mm on 4x5.

MattKing · May 18, 2023

FWIW, the RB67 lenses are, in most cases, designed for 6x8 coverage, and in fact there are backs that permit using them with 6x8 - in portrait orientation.
Your other comments are correct.

abruzzi · May 18, 2023

one possible benefit of adapting RB lenses is I believe that the wide angle lenses on a RB are all retrofocal so they don't interfere with the mirror, so if you can focus a 100mm lens to infinity, you can focus any RB lens to infinity. (the FFD on RB lenses is 112mm, so even the 37mm fisheye gives you plenty of space.) On the negative side, the wides are the least likely to cover 6x9, unless you're focusing clock.

I have that RB adapter board I linked to, but I haven't done anything with it yet, but I thought it might have some use so I snagged one a while back.

xkaes · May 18, 2023

abruzzi said:
one possible benefit of adapting RB lenses is I believe that the wide angle lenses on a RB are all retrofocal so they don't interfere with the mirror,

The long flange focal length of the wide-angle RB lenses won't be of much help because the image circle is still pretty small at infinity. You might be able to squeeze a little shift out of them, but no much. Better than nothing, I suppose. It sure would be a help with macro work -- however it would be smaller, lighter and cheaper to get a normal LF macro lens.

I no longer have any RB lenses -- except the fisheye. The only one that makes any sense on 4x5 is the 37mm. If using a medium format back, it seems more sensible to stick to the lenses you have -- or get some wider optics if needed. If you have a 90mm, 75mm, 65mm or whatever, even if it covers more than the roll film back, why not use it -- for both formats?

reddesert · May 18, 2023

I don't have a Chamonix but I'd think the C2n holder would work on it, it typically fits like a regular slide in film holder. It is not really very heavy. However, two things: you should read the instructions for the C2n carefully, and pay close attention to the loading instructions; and you may want to pull the GG back as you slide in the holder. In some combos of back and holder, it's possible for the holder to contact/scrape on the glass.

The main complaint some people have about the C2n is the curve in the film path, if you leave film in it for a while, it may take a set at the point where it makes a 180 deg turn.

xkaes · May 18, 2023

Reloading the C2N is not like riding a bicycle. If you need a copy of the instructions, I can upload it. Mine is 6x7, but I assume the 6x9 is the same.

abruzzi · May 18, 2023

xkaes said:
The only one that makes any sense on 4x5 is the 37mm.

I thought the discussion was about roll film backs--6x9--not 4x5? And in your quote of my post, you clipped off the part where I stated exactly that--image circle will be the most limited on wides since they're least likely to have generous image circles. Of yourse people will have to make their judgment for themselves. If the have a 6x7 it will likely work well, a 6x9 will depend on the lens and how close you will be focusing.

Jimi3 · May 18, 2023

Thanks all. I just got the C2n from KEH and it seems pretty secure when attached to my 45f-1, so I think it’ll work well. Watched a video on YouTube, loaded up a 15 year old (cold stored) roll of plus-x and now I’m off to try it out.

Jimi3 · May 18, 2023

I think I might skip the hassle of adapting a medium format lens, at least for now, and just get an ultra wide for 4x5. That fisheye setup looks sweet though.

xkaes said:
You can adapt RB67 lenses to a 4x5 (or other) LF-sized cameras, but they are designed for 6x7 coverage, not 6x9. -- as Matt mentioned Plus, they are all very large and heavy -- although prices are pretty reasonable nowadays.

Here's how I adapted my RB 37mm fisheye. Works fine -- because it's a fisheye lens -- once you get used to how the shutter has to work, that Dan and Matt mentioned. That adapter board makes things much easier, but won't change the coverage limitation, the weight, or the size. The 37mm weighs about three pounds, for example.

http://www.subclub.org/fujinon/gonefishin.pdf

If you don't mind a little cropping, then you are all set, but in that case, if you are OK with cropping just use regular, in-Copal, 4x5 lenses. Better yet, since the 6x9 format gives you a narrower picture angle, just use a longer lens. If you want to keep the extra-wide picture angle, there are plenty of 6x7 lenses to choose from -- but a 50mm on 6x7/6x9 is very different from a 50mm on 4x5.

xkaes · May 18, 2023

abruzzi said:
I thought the discussion was about roll film backs--6x9--not 4x5? And in your quote of my post, you clipped off the part where I stated exactly that--image circle will be the most limited on wides since they're least likely to have generous image circles.

Despite my "clipping", I am agreeing with you. However, I was pointing out that the 37mm is an exception because it is a full-frame fisheye on the 6x7 format. By removing the lens shade it makes a perfect circular fisheye image, much like a 7.5mm/8mm on 35mm film. Of course you have to stick to a 4x5 inch format to achieve that, but it would work fine on a 6x7, 6x9 -- and maybe even a 6x12 -- film back.

Roll film back questions (Cambo C2n)

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