RB67 advance issues with any film back including unused, new in box ones.

[Certain Exposures]

Every single film back I have used with my RB67 ends up failing to advance film correctly while using it out in the field. I purchased a new, allegedly unused (and I believe it based on the box, plastic, and condition) 645 Pro SD film back and it did the same thing on the first roll (which happened to be this photoshoot).

I have had this camera and back and a lens serviced already. The lens is ok. However, the body and film back returned with familiar operational problems, including this one. The repairman said he could not replicate my issues. Do any of you have any theories about how this is could be a 'me' problem?

When I shoot a roll, eventually, the 67 or 645 back does the following:

1. The lever keeps advancing past the point it should instead of stopping.
2. If I continue to pull the lever it gets locked all the way out.
3. The film frame counter stops in a random position in between frame numbers.
4. The red 'exposed' flag in the film counter appears and doesn't go away with subsequent turns of the lever.

Every single film back does this randomly on most rolls.

I can get around this when it happens by guesstimating the stop position and using the double exposure feature. That is no way to enjoy a photoshoot, though.

 

[mshchem]

I would suspect dryed out solidified grease. I've had issues with old Hasselblad backs not stopping at 1. I have used a bit of a solvent, and freed it up. This is common with beautiful old unused cameras. "Shelf Queen".

 

[MattKing]

It is an issue with the safety interlocks.
The fact that it happens with several backs tells me that it originates in the camera.
Does it happen with more than one lens?

 

[Certain Exposures]

Yes, it happens with several lenses.

 

[MARTIE]

Long shot... does it only happen when attached to a tripod?

It's unlikely the repairman uses it on a tripod.

 

[Certain Exposures]

I only use the camera on a tripod because I find it awkward and heavy to use handheld. Why do you believe the problem would be caused by a tripod?

 

[MARTIE]

I've known the screws can be (overly) tight and mess with the camera.
Easy to test.

 

[itsdoable]

I only use the camera on a tripod because I find it awkward and heavy to use handheld. Why do you believe the problem would be caused by a tripod?

On some cameras, there have been cases where the tripod screw is a little to long, and distorts the bottom of the camera, causing issues like this.

 

[Certain Exposures]

OK, are there any threads out there where someone has realized that this impacts a RB67? I will search in the meantime. I am surprised because it seems so unlikely. I don not see a connection between the tripod mount and the safety locks or advancing.

 

[MattKing]

The other thing that used to affect me regularly was a very minor issue with the rotating adapter. If you don't rotate the back fully to either of its rest positions, the interlocks don't necessarily behave as expected. A slightly worn rotating adapter makes that more likely.
The issue with the tripod mount is probably sort of similar - anything that slightly prevents the parts of the camera from lining up the way it was designed to can confuse the interlocks.
And of course, all of these factors can end up working together.
A lot of RB67 bodies and backs and rotating adapters have seen a LOT of use.

 

[reddesert]

I assume you have an RB67 Pro S or SD body and film holders where there is a body to back interlock for double exposure prevention - it's the pin at upper left (photographer's left). (Edit: actually I think there is even a interlock on the early Pro body/holders, but it just activates a warning signal rather than a mechanical prevention.)

If you save a roll of 120 backing paper on a spool (always save a roll of backing paper), you can test the film advance ad infinitum without wasting film, by loading and winding just the paper. It may get the spacing off because of the different thickness, but it should work fine for testing cocking/winding.

You can test the film holders off camera, by just winding the paper and then flipping the release lever at the rear to wind to the next frame. You can also imitate the camera interlock to trigger "exposed" by poking the little port where the interlock pin goes with a small screwdriver or similar. This should pop up the exposed indicator and free the wind lever. You can also watch how the camera fires that pin, firing the camera with no back attached.

Although IIRC there is only one shutter/wind interlock on an RB, the interlock pin business is a little complex because it has to also work when the revolving back is rotated 90 deg. So IIRC there are two camera body pins that shoot out, but the revolving adapter relays one or the other depending on position. Anyway, it's not too hard to visually verify what the interlock is doing, unlike inspecting the wind gearing, for example. I would check very carefully to make sure the interlock is lined up right, as MattKing suggested.

 

[reddesert]

Another thing - something that I think can happen, although it seems unlikely it would happen in every film holder you have, is for the film counting roller to slip. I got a film holder out to try it, and I think the backing-paper-only test isn't 100% reliable if you wind a loose roll and the film counting roller slips on it.

It seems unlikely this would happen with real film on every film holder you have, though, unless you were using a film with extra-slippery backing paper (if there is such a thing). I think there is a Photrio thread where people discussed issues with a RB67 holder slipping counter roller.

 

[neuromantism]

Well, I know it's a silly question, (cause maybe it's been already asked) but are you using the correct film back with the correct film? Or is there a chance that you use 120 film in a 220 film back holder (or the other way?)

 

[Certain Exposures]

Well, I know it's a silly question, (cause maybe it's been already asked) but are you using the correct film back with the correct film? Or is there a chance that you use 120 film in a 220 film back holder (or the other way?)

Yes, I am. It is not a silly question. I used to use a 220.

Another thing - something that I think can happen, although it seems unlikely it would happen in every film holder you have, is for the film counting roller to slip. I got a film holder out to try it, and I think the backing-paper-only test isn't 100% reliable if you wind a loose roll and the film counting roller slips on it.

It seems unlikely this would happen with real film on every film holder you have, though, unless you were using a film with extra-slippery backing paper (if there is such a thing). I think there is a Photrio thread where people discussed issues with a RB67 holder slipping counter roller.

Kodak Gold 200 wrapping paper is very, very slippery so I wonder if this might be the cause. I am not rolling a loose roll, though. I am loading the roll wound tight just like my TLR (which never does the same). Do you know people solved the slipping?

Am I incorrect that the interlocking system is independent from film advancing? I.e., there's no way an issue with interlocking would explain the advance slipping and failing to register begin/end points of frames.

There is definitely an issue with the rotating adapter failing to register the action of the PRO-S body sometimes. However, that just means the body won't fire. This all occurs without a tripod.

I feel disappointed with my service because the issue has been easy to replicate and has stuck around. I suppose I could be using the camera in some odd-ball way. I doubt it, though.

 

[MattKing]

Am I incorrect that the interlocking system is independent from film advancing? I.e., there's no way an issue with interlocking would explain the advance slipping and failing to register begin/end points of frames.

There is definitely an issue with the rotating adapter failing to register the action of the PRO-S body sometimes. However, that just means the body won't fire. This all occurs without a tripod.

I think you are incorrect here, because the interlocks do control how the camera communicates the fact that the shutter is cocked and then released with the frame counter mechanism.
And of course, the actual winding energy comes from the body via a gear connecting with a gear in the back. If that gear connection is hanging up or is blocked in some way, it may very well result in the film being only part way advanced.

 

[Certain Exposures]

Okay, thank you.

 

[Arthurwg]

Don't worry, you're not alone. I have similar problems with my Pro SD.

 

[Andrew O'Neill]

I've never heard of this issue, and I've been using my RB pro SD since '93...

 

[reddesert]

I think you are incorrect here, because the interlocks do control how the camera communicates the fact that the shutter is cocked and then released with the frame counter mechanism.
And of course, the actual winding energy comes from the body via a gear connecting with a gear in the back. If that gear connection is hanging up or is blocked in some way, it may very well result in the film being only part way advanced.

Matt, this is an RB67, not an M645. (The mention of "645 back" in the OP may have led to confusion?) The body doesn't wind the film via a gear. You wind the film with the lever on the roll holder.

I strongly suggest loading one or more roll film holders with a spool of backing paper, and testing it several times just winding the paper through, poking the little interlock hole (top left of film holder) with a small screwdriver or tool to release the wind lock, and continue, and continue again, to understand the sequence and see if you can get the error to occur. I just did this while testing for this post.

The roll film holder, when it reaches the new-frame position, clears the red "exposed" flag from the frame counter. You can feel a little click at the end of a wind. When you poke the interlock as if you were the camera firing, the red exposed flag will reappear. Then you can wind again, and so on.

I tried holding the tool in place as if the camera's pin were failing to retract, but I don't think that makes the wind lever slip. It's something to check, anyway.

The fact that it happens on multiple roll holders suggests perhaps camera misbehavior, slipping frame counter roller (perhaps the film type is the common element), or something in your wind technique maybe. You really have to dry-test it (test winding with spools of paper, test with back off the camera, etc) to have any idea.

 

[MattKing]

Matt, this is an RB67, not an M645. (The mention of "645 back" in the OP may have led to confusion?) The body doesn't wind the film via a gear. You wind the film with the lever on the roll holder.

Oops - it was the RZ67 I was thinking of here.