Buying and using

Overview

As is hopefully clear, the camera I'm selling is just a body — no lens, and no film back. To use it you'll need to source those. I’ll cover the film back first because it’s easiest.

Film backs

The camera is designed around film backs for the RB67 Pro and Pro S cameras.

IT WILL NOT WORK WITH BACKS FOR PRO SD CAMERAS.

Annoyingly, Mamiya chose to close in the end of the Graflok 23 mount on those backs. That wasn’t an issue for the “jaws” in their film back holder, but I’m not a fan of that kind of locking system for a back that needs to be frequently removed. So I’ve gone for a slide-in / slide-out design — which works great, but means Pro and Pro S only.

This is a bit of a shame because Pro / Pro S backs rely on foam/felt seals around the door that eventually need replacing. But honestly my experience is they need to be pretty fully gone before you start having problems, and swapping them isn’t hard.

Pro vs Pro S? Both will be fine. Pro S backs are maybe more plentiful and add a little safety lock so you can’t remove the darkslide while the back is off the body. That’s actually a pretty handy feature, so I’d lean that way.

If you want to avoid potentially dodgy old backs on eBay there is of course Albert’s freshly designed back, which is built brand new.

Lens

The other critical thing is of course a lens. The camera is designed around “lens boards” that thread into an M65 helicoid, which is used for focusing. These lens boards can be drilled for Copal 0 or Copal 1 (or equivalent Compur) shutters. If someone needs one for a little Compur 00 let me know — I can do that too, but won’t bother listing it on the product pages. Generally the focal lengths that will be interesting for this camera will be in size 0 shutters, which fit nicely.

Because we’re talking about used lenses, shutters will of course be of variable quality. I’ve bought a lot online and in used camera stores at this point. My overall experience is: if the shutter timings are completely out, the ad will usually say as much — but there are plenty around with pretty accurate speeds. Shutters with a preview lever are useful, but not essential.

What focal length?

6x7 film is about a 90mm diagonal, which is close enough to double 35mm that I think “cut the focal length in two” works well as a rule of thumb. I also find that because of the movements available on the camera — and the ability to control framing more precisely — lenses feel wider (or more correctly: they have more useful width). To that end, I rarely want wider than 65mm even though 32.5mm on a 35mm system wouldn’t be seen as particularly wide. But that’s me, and your mileage may vary.

Beyond focal length, the other thing to look for is image circle. The lens table I’ve prepared includes it for a lot of lenses, but it’s not exhaustive — I’ll keep extending it over time.

A 6x7 frame only needs ~90mm of image circle… but we’re here for the movements. If you want to max out rise and horizontal shift at the same time you’ll want about 150mm of usable image circle. That’s the extreme end of use, but I personally like knowing I’m at no risk of running out of coverage or seeing really rubbery corners.

There are a few lenses built for 4x5 use but with no real movements (I’m looking at you, 90mm Angulon) that tend to go cheap because they aren’t great for their intended use — but end up being great for my system.

Choosing lens cones and lens boards

Because large format lenses are generally not telephoto or retrofocal designs, you can assume the flange focal distance (FFD) will be approximately the same as the focal length.

If that means nothing to you: basically the back side of the Copal shutter needs to sit on a surface that far from the film plane to be in focus at infinity.

So if you use a 90mm lens you need a lens cone such that the FFD (going to be ~90mm, plus/minus a few mm) lands in the right place with the helicoid wound most / all of the way down. In my camera design, this stack is made up of the body itself and a lens cone, a focusing helicoid, and a lens board.

If you're wondering how the different thickness lens boards work, here are some cross sections that hopefully explain it - the additional offset is achieved around the lens, the section of the board the lens mounts to is always the same thickness.

This can of course be finessed so the end stop of the helicoid is exactly at infinity — but honestly, even with my own lenses (where I can adjust the size to be sub-mm perfect) I just don’t bother. I’d rather be able to focus slightly past infinity than think I have it perfect and go on an overseas holiday to later realise I screwed up some calculation and one of my lenses can’t quite get to infinity… or even past about 5m focus (ask me how I know about this…).

Focus throw chart

I’ve put a chart below to demonstrate why this is true. Basically, focus movement vs focus distance is very non-linear: most of the practical effect happens in the first couple of millimetres near infinity.

This changes with increasing focal lengths in a non-linear way, so if you’re shooting a 300mm lens on 8x10 you do need to maximise available draw. But for the focal lengths that make sense on this camera, the throw of readily available M65 helicoids is pretty generous.

The chart shows this well: with a 65, 90, or 105mm lens, if you nail the infinity stop position then the 14mm throw of a 17–31mm helicoid gets you focusing under 1m. That’s beyond ample for what this camera is intended for.

And if you end up with a slightly too-short cone (so the first 1–2mm of throw focuses past infinity), close focus hardly suffers. Conversely, if you overshoot and the cone is too long, you can have massive problems even if it’s only 1mm too long. (In my problem case: 50mm lens, cone 1mm too long, and my longest focus was something like 2.5m to 3m. Fine sometimes, often no good.)

I’ve included the 135 and 150mm lines mostly to show what longer lenses do to close focus distance. I still think you won’t want to be focusing closer than ~2m that often, but I don’t want to preclude the occasional portrait. So I’m suggesting lenses >105mm ship with a 25–55mm helicoid, which should give all the focus reach you could ever need.

Basically the goal is to hit within ~2mm of the FFD using one of the available lens cones and one of the available lens boards. The lens boards have different standoffs (all boards are 1.5mm thick at the mount point, but differ in effective thickness at the shutter).

You can then close the gap at the helicoid stop with shims. Each lens cone will ship with 2mm worth of aluminium M35 shims: 1×1.0mm, 1×0.5mm, 1×0.2mm, 3×0.1mm.

Why 2mm and not less? I can see not wanting to need to use too many shims for a simpler setup - so if you want to ignore my advice an order a 1mm thicker lens board to reduce the shims needed then you obviously can, but you do it at your own risk. The data in the table is already provided on a best efforts basis and even then manufacturers did subtlely change some lenses through their production lives and there can be sample to sample variation.

The idea is you find your lens, and the lens table tells you what cone / helicoid / board thickness is recommended, with the rest optionally made up by shims. As I say on that page: I’ve done my best to compile a good list, but it doesn’t cover every lens, and the data is only as good as what can be scavenged online (plus how consistent the manufacturer was to spec). That’s why I suggest you shoot low on the cone + board combo and shim up.

Why have I shot for 1-2mm of shims and not less? I can see not wanting to need to use too many shims for a simpler setup - so if you want to ignore my advice an order a 1mm thicker lens board to reduce the shims needed then you obviously can, but you do it at your own risk. The data in the table is already provided on a best efforts basis and even then manufacturers did subtlety change some lenses through their production lives and there can be sample to sample variation. 

If you want to sanity-check a lens you already own: you can mount it on a large format camera and get clever with calipers, but it can be tricky to get a really good number. Below is a decent “good enough” method to confirm the table value to within ~2mm.

Make a tube of card/stiff paper that’s the target infinity FFD, with a diameter big enough to clear the rear element. Put frosted tape across one end to act as a “ground glass”. Open the shutter with the preview lever, “mount” the tube against the rear of the lens, and point it at something far away (at least hundreds of metres). The tape should show a sharp image.

If it’s sharper on something closer, the infinity FFD is shorter (reduce the tube length and confirm). If it’s not sharp at all, the lens is focusing past infinity — if it’s almost sharp, you’re probably within shimming range (or you’ll just mount up focusing slightly past infinity, which is not a big deal, per above).

Fat rear elements

You’ll see in the lens table that some lenses are marked as not recommended because their rear elements won’t fit in an M65 helicoid. The throat of these helicoids is 61mm, so if your lens has a rear element diameter bigger than ~60mm it’s not going to work.

This mostly hits Fuji lenses. I think in their mission to make economical lenses, Fuji went for highly symmetrical designs (and also not cemented — just air-gapped), which is smart optical design but sadly can mean some really massive rear elements.

If you already own a lens I’ve marked as “not suggested” and you really want to use it, send me an email — we may be able to work something out with a bigger M77 helicoid, but it’s not something I’m offering as standard.

Do you need a centre filter?

When you start researching wider lenses for this camera (say wider than 75mm) you’ll see a bunch of old forum posts about shooting 4x5 with these lenses, and some views that a centre filter is essential. That’s probably true on 4x5 where you’re using the whole image circle, so all the fall-off gets picked up in a strong circular vignette.

With this camera we use a fair bit of image circle, but not all at once. Generally the lens is shifted upward into the fall-off, and the fall-off ends up looking much more linear — more like a graduated ND darkening from the top down.

In some ways this is a free kick: it’s often nice to add a graduated ND to darker skies anyway, and this can do that for you. I certainly use my graduated ND set a lot less with this camera.

If you do want to correct it, I’d suggest a graduated ND setup to darken the lower part of the frame is a much cheaper solution than a centre filter, which have become extortionist in pricing… but honestly my advice would be to not correct it and see how you go.

If you’re scanning (and I’m guessing many will be), any fall-off you don’t like is easily corrected. But even if your workflow is entirely analogue (godspeed), I bet the baked-in “ND” is rarely detrimental.

Tripod

If it’s not obvious: this camera is for tripod use only, so you’re going to need one.

(Note: I have a fairly advanced prototype of a hybrid optical/electronic viewfinder that projects framelines for different focal lengths, with frameline adjustments for rise. That would allow handheld use… but every time I play with it I feel like it’s just too imprecise, and I’d rather just pull out the tripod.)

The camera is pretty light so you don’t need monster legs. I’d say 95% of the photos I’ve taken with mine have been on the Peak Design Travel Tripod, which I really, really like. When I’m in Australia and have a car I use some chonky Manfrotto 055 legs that I can get sand and salt water on and not care about. They do feel a bit more solid in use than the Peak Design, but not in a way that seems to meaningfully impact photos.

Tripod head

More important than the legs is the head, which I strongly suggest should be geared. This camera is about lots of small movements, precisely, and it’s a much nicer experience if the head works the same way. I have used mine with a ball head and it’s… frustrating.

You don’t need a fancy geared head. I’ve gotten amazing mileage out of a Leofoto G2 and I think it’s a perfect pairing for the size and weight of the body. It’s got a little backlash in the movements, but not enough for me to want something bigger or heavier.

The tripod attachment point (1/4" threaded) is also an Arca-Swiss compatible plate, so it’ll fit into a lot of heads without needing a separate plate.

Cable release

Probably goes without saying — but for anyone coming to this camera without a large format background: you’ll want a cable release to reliably capture sharp photos on a tripod.

I personally love the ones Nikon used to make (and wish they’d never stopped!) and I think they’re worth the money. The wooden grip is drilled with a little flare at the end which should receive many cable release heads, but I can vouch 100% that it fits the Nikon ones.

(And yes: if you leave it in there while shooting it kind of defeats the purpose. But I find the drilling is useful for transporting the cable release between walking stops so it’s not just swinging around.)