An MF Film Format Question

Pfiltz · Jan 26, 2013

I have an Mamiya RB67 camera, and use it just every so often. It's my first film camera. I also shoot 4x5 as well.

With regard to my RB camera and the film back, do they have different film backs for it? I don't mean 120 -vs- 220. My current 120 back, say's 645 on it. Are there larger format sizes that will accommodate my RB? Does that make the image size larger as well?

Sorry for the newb question, but I've never really shot a lot of film.

markbarendt · Jan 26, 2013

There are various sizes. 645 is the smallest but gives the most frames per roll. Then 6x6 is supposedly available, never seen one but I think it would be fun to have someday. Next up is 6x7 is the most common. There is also 6x8 I think, which if memory serves, requires a special mount, in place of the rotating mount.

Pfiltz · Jan 26, 2013

Thanks Mark. I think I'm going to try to see if I can find a 6x7 back. Do I just need the film insert or the whole back for my RB?

cjbecker · Jan 26, 2013

The 6x7 back is going to be the easiest one to find as it was the normal one for that camera.

markbarendt · Jan 26, 2013

Need the whole back, the opening is different.

tkamiya · Jan 26, 2013

RB series camera bodies were designed as 6x7 camera. For this size, you get a 6x7 back and remove any masks in the view finder if any. When you look into your view finder, do you see a cross looking opening? (picture attached) If so, take off your view finder and remove this thing. Now you'll see the whole film area for 6x7.

You can also get 645 back (the whole back, case and the insert) and this mask.

You can also get 6x6 back (the whole back, case and the insert) and I'm not sure about the mask

Or, you can get 6x8 back. This is a power back that winds electro-mechanically. There are two types, one with integral battery and one with an external battery pack. It is supposed to come with a new focusing screen. If you have an older type body, such as Pro or an older Pro-S without "8" on the body behind the rotating back, you'll need to replace what is called a "buffle". Pro-SD does not need any modification.

By the way, that's a heck of a camera for your first film body!

Ric Trexell · Jan 26, 2013

That is why it is called RB67.

Pliftz: You didn't say if your camera is a Pro or Pro S model, (or Pro SD) but if yours is just the Pro, all the other model backs will fit it but the others have interlocks. They will not work on the Pro, but if you have a Pro S or SD, you should try to get the proper backs. You will pay more for the Pro S back, but since the interlocks won't work with it, you would just be wasting money. The interlocks prevent certain things like not tripping the shutter if the film is not wound, and the back not straight or the dark slide being in place and probably a few I forgot. The reason the RB67 is called that is because of its 'revolving back' and the fact that it will take 6X7 pictures. You can probably sell the 645 and pick up a 6X7. You can also put a polaroid back on that camera, but I suppose you know that. Have fun. Ric.

Pfiltz · Jan 26, 2013

Appreciate all the info guys.

I have the RB67 professional S body. That's whats on the back as well. The back rotates from one orientation to another. I don't believe there is any mask under the prism finder and/or WLF. There is a piece of glass that will come out, but I don't think it's a mask. I do see some dotted lines and a red line based on which way the back is turned.

I'll scout around FleeBay to see if I can find a whole back in the 6x7 flavor. I'd like to get the most out of the camera if I'm going to use it.

Yeah, if I know then, what I know now, I would have never gotten this BEAST. I wanted to shoot MF, and found what I thought was a really decent deal on it.

Body, 3 lenses [50mm, 180mm, 250mm], 3 backs, filters, (2) prism finders, suitcase with velvet inserts for all the pieces for 500.00. I bought someone's darkroom equipment, and a WLF was in the deal Kind of getting use to that one though.

Now that I've gotten shoot with or "workout" with this monster, I would have liked to gotten something with a smaller footprint, like a blad or rollie.

tkamiya · Jan 26, 2013

Hey....

I think you are missing the mask, if that's all you have. You'll just have to be aware, what you see on your view finder isn't what you are going to get on your film. (because film is smaller) I think you did get a pretty decent deals.... You got a lot for $500. I think once you get 6x7 back, you may begin to appreciate the size of the negative.... with 645 back, you really aren't using your camera to its full potential.

MattKing · Jan 26, 2013

The 645 backs are good for transparency film, if you have a 6x6 projector.

Here is a pdf of the 645 mask that you can drop into your viewfinder to show you how the image is framed.

It should be accurate.

Pfiltz · Jan 27, 2013

Thanks folks...

I have a 6x7 film holder for my enlarger, hence, me wanting to get the larger back for my film. So far, I haven't seen one for my RB67 on FleeBay. I may check out KEH or some other camera outfit such as B&H.

markbarendt · Jan 27, 2013

Make sure it comes with the dark slide.

Also understand that simply because of age many, if not most backs, may need new seals. There are kits available to replace them and there are inexpensive. The job isn't real tough but it is time consuming especially the first time.

tkamiya · Jan 27, 2013

For whatever reason, KEH is constantly running low (or non-existent) on RB backs for quite a while now. As of right now, there are none left and when one shows up, it goes fairly quickly. Be quick about it if you want one.

... and oh yeah, you'll be competing with me on quickness!

Pfiltz · Jan 27, 2013

tkamiya said:
For whatever reason, KEH is constantly running low (or non-existent) on RB backs for quite a while now. As of right now, there are none left and when one shows up, it goes fairly quickly. Be quick about it if you want one.

... and oh yeah, you'll be competing with me on quickness!

I noticed that...

BUT, I have an inside track to sales there ... LOL

xtolsniffer · Jan 29, 2013

The 6x7 backs do go quickly! A few years back there were lots around for peanuts as the pros dropped their RB67's onto the market and went digital. Now a lot of people who could never afford such a magnificant camera have them and demand has picked up again. A brief note on the backs: Pro ones, pretty old now, no interlocks so you have to be careful over double exposure. ProS, most common, usually need the foam seals replacing, it's a easy (but messy) DIY job of about an hour, materials and instructions are available on the web. ProSD have no foam seals, so that's not a job you have to do, plus have a little place to store the darkslide when it's out so you don't use it. Beware, there are a lot of 220 format ones out there as 220 format film is dwindling (120 gives ten shots per roll, 220 gives 20 shots) but as the film thickness is different since 220 doesn't have the backing paper, it's not a good idea to use 120 film in a 220 back). 220 ones are cheap and easy to find, 120 6x7 less so. happy hunting!

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