Mamiya RZ67 Back 120 / 24 Exp (?!) - weird problem

hi there,

I recently acquired a Mamiya RZ67 with two lenses and a 120 back. I'm having some strange problems concerning the back:

- the back says 120 (the number is 'framed', and looking at some backs in real and on the web, this is pretty normal)
- below this 120, it says '24 Exp'
- the back is definitely 6x7, it can also revolve, so far so good, but..

- it does not produce 10 single frames on a 120 film. it produces a seemingly endless succession of - here comes the funny part - about 24 exposures which are overlapping.. I will try to scan it somehow as it is difficult to describe, but it's just like after one third of an image, the next image 'begins', and it's just one big mess
- accordingly (?!) to this one-third-image thing, the counter in the back does not start with 1, but with 11. It then goes on with 11, 12, 13, 21, 22, 23, 31, 32, etc.
- When advancing the film by cocking the shutter, it feels very much like the film wouldn't be transported far enough. Before the halfway point, the wheel on the film back stops turning, when I push down the cocking lever further it makes a strange sound and finally cocks the shutter and releases the mirror. Like it would turn operate in idle, which it seemingly does, as the film is not transported further.

- So I don't really think it's a malfunction of the back, as the weird numbers in the frame counter indicate it is seemingly supposed to do 8x3 exposures.
- But why on earth are they overlapping? And what's the point behind all this in the first place?
- The camera is completely useless to me in this condition.

Basically I am left disappointed, and puzzled. I have two main questions:
- What weird kind of a freak back do I have? I really tried my best to look it up on the web, but just couldn't find anything on the back.
- Is there any chance to make it operate as a normal, 10-6x7-exposures-with-frame-borders, back?

Please help,
sewarion

Well, here is the promised 'scan' - as I do wet printing only, I had to photograph it with a small digicam, but it becomes clear what I am talking about anyway:



What makes me think of malfuction is, well, the result in the first place, as I can't think of a way of intending this mess. There is also the strange/incomplete cocking action by using the lever.

But then I get puzzled again by 11-12-13-21-22-... and the '24 Exp' designation.

Any ideas, suggestions, anything, anyone?

sewarion

That is weird. Never heard or anything like that. Fortunately another 120 back should be cheap and easy to find.

I have a Mamiya RZ with a back that has a stripped nylon gear and sometimes the frames touch and spacing is uneven. Buy another RZ back or have the old one repaired. You can also buy a new 120 insert.

Does the "24" look like an after-market add-on?

I wonder if someone has modified the back, with the intention of inserting some sort of mask, all to permit 24 pictures on a roll.

Something for stereo photography?

Thanks for the replies..

I think that buying a new back is inevitable. I'm just annoyed as this was my personal 'big step' up from 35mm and it starts with a malfunctioning camera, hassling with the seller, etc.

The only thing that really puzzles me is that I have no idea what kind of a back I ended up with: It's not only the way it counts the frames (11-12-13-21-...), but also the '24 Exp' thing. I did some serious googleing on it but couldn't find anything of the like:



MattKing, it doesn't look aftermarket at all to me, but pretty much 'original'. Whatever that means, as I can't get any information about it at all.

sewarion

It's not intended to be used with a 35mm adaptor, is it? That gives you 24 mm by 65 mm panoramic exposures. If it is, you need to rotate the film pressure plate to set it back to 120 format. Easy to find out - if the pressure plate will rotate, rotate it and see the difference.

Looks like a 6x3cm back. I believe the little white rectangle indicates the orientation of the frame.

Wow. And why then the overlapping images? Because the 'hole' (film area to be exposed) is clearly 6x7, not 6x3.. can this be some mask missing or so?

I've never seen such a thing either, but I think ic-racer is right about "6x3 back missing its mask". 24 exposures would be right for the 6x6 220 back (which exists) but it clearly says 120 on there. Your recourse to the seller is to ask to get the proper mask for it. I don't have my RZ here but I suspect the mask is part of the outer part of the back while the advance mechanism is definitely in the insert; it's possible the seller has inadvertently swapped things up and there's some poor bastard out there with a 10-frame back that shoots 6x3cm with massive gaps...

Otherwise, you can get good 120/6x7 backs for about $50. Get a couple at least so you can switch between colour/B&W, fast/slow or whatever.

You might have a rare and useful back that's missing a 6x3 mask. Keep it.

I wonder if there was a "35mm panorama on 120" back manufactured just for a particular market, like Japan?

I will definitely keep it. Maybe the seller will send me the masks (though I doubt he does even know what he sold, nor that he has the masks), or I will try to make them myself from thin metal or so one day. But first, of course, I need a 6x7 back (which are about 80-100 euros here [Austria], rather than $50).

MattKing, I just measured the width of the first image before it becomes overlapped by the second: 24mm. This would make the ratio 1:3, which I find pretty cool. It takes only roll film, though.

Thank you so much for your replies and your help,
sewarion

edit: There is need for spacing, of course, and the 'long' side is placed vertically on the roll film - so it would be about 22x56mm - roughly about 1:2.5 ... still not bad

KEH will ship to the EU too. Barely worth it for one back, but if you're getting a bunch of stuff (say three backs and a lens) then the prices are very good.

I get stuff sent to Australia because our prices are even worse than Europe's.

Thanks for the info.. but I'd have to get the stuff through customs which means adding about 20% to the total value. This plus the shipping costs eats up the price advantage pretty quickly, unfortunately.

The very earliest of RZ film backs did not have a directional arrow printed on the advance knob.
From your image of the back...this would appear to be a back from the early days.
Also, a normal 6 X 7 back will show the 'landscape' icon when the back is positioned...'knob-up.'
Your back, with the 'knob-up'...shows the 'portrait' icon.
(Likewise, a 645 back would also show the portrait/landscape icons in the same orientation as your back).

Lets do a little exercise in math. A roll of 120 film is about 790mm long.
How about we allow for a 20mm lead-in, and another 20mm for a tail-end.
There would be 23 spaces between frames, for the 24 frames...lets try 6mm(?) times 23.

6mm X 23 = 138mm; plus the 40mm at the ends = 178mm; 790 - 178 = 612mm.
612mm divided 24 exposures = 25.5mm per frame.
That comes pretty close to your measurements of about 24mm per frame.

As everyone has said, this may be a one-off oddball...from the early days.
Your idea of making a mask and using the back in 'panorama/landscape' mode, may be just the ticket.
Run a roll of sacrificial film through the back, with lens removed...mark the frames on the film with a Sharpie.

Have fun!

Marc

PS: Can you shoot us an image of the 'start point arrow' on the film insert?

Thanks for the maths. I just measured the 'steps' on the wasted film roll again. 28mm. This seems to be the distance the film gets advanced when cocking the shutter, and in theory I can now even define the spacing between the images, and thus image height, myself, or not? Say, if the film gets advanced 28mm every time.. so I could have 24mm height with 4mm spacing, or 22mm with 6mm and so on, depending on how I cut the mask. Would that be correct?

Start point arrow? I assume you mean the marker on the inside, hence I made an image with the back opened. You can even see the serial number (150779), maybe anyone knows some sort of list or so which might help to locate the back in space and time.



sewarion

OK...the start point isn't unusual.

Make your mask, find the center, make opening in the mask...say, 23 or 24mm.
Shoot a roll of film...see what the actual spacing is between frames...whole roll.
If you think there is enough spacing, you could then enlarge the mask...out another (?) mm's.

Once you run a few rolls of B&W through this back, and, if you don't process your own color film,
you will need to tell your color lab how you want the images printed.
The image size will blow their minds. Or...at least it will be unusual for them.
They'll probably need to cut masks, too...printing optically, or scanning digitally, (depends(?) on the scanner).

Without special instruction, they may put two (2) images per photo, (just like the labs do with half-frame 35mm).
Dealing with the labs on this very issue...that may be why this back was not mass-produced.

Marc

I've owned an RZ for over 30 years and have never seen a back like this one. My questions is how do the view finder masks look like when that back is on the body? Correct me if I'm wrong, but the masks is an indicator of format.

Unless the seller has both the film-plane mask, and the focusing screen mask, (doubtful),
all you need do is mark the focusing screen with a marker to indicate the format lines.
Not much different then the markings for 6 X 9cm or 6 X 12cm roll film back
on a 4 X 5 inch GG...only smaller scale.

56x24 is about 2.35:1 - my guess is that this is aimed at replicating the Todd-AO/Panavision formats (~53x23mm) of 65mm/70mm motion-picture film using 120. It would permit the shooting of stills from a movie set in the same aspect ratio and film size as the movie camera.

Mainecoonmaniac said:

I've owned an RZ for over 30 years and have never seen a back like this one. My questions is how do the view finder masks look like when that back is on the body? Correct me if I'm wrong, but the masks is an indicator of format.

Click to expand...

Well that's what I hear about the back, nobody has ever heard of it. One good reason for keeping it. I will surely try to get it into use, if I figure the masking thing out. For now, I just purchased a 'normal' 120 back and will finally start shooting 6x7 tomorrow or so.

Thanks for your help, really appreciate it.
sewarion

edit:

polyglot said:

56x24 is about 2.35:1 - my guess is that this is aimed at replicating the Todd-AO/Panavision formats (~53x23mm) of 65mm/70mm motion-picture film using 120. It would permit the shooting of stills from a movie set in the same aspect ratio and film size as the movie camera.

Click to expand...

That sounds seriously interesting. I might contact Mamiya and ask them if there were any special models for the movie industry or the like.

sewarion said:

Thanks for the maths. I just measured the 'steps' on the wasted film roll again. 28mm. This seems to be the distance the film gets advanced when cocking the shutter, and in theory I can now even define the spacing between the images, and thus image height, myself, or not? Say, if the film gets advanced 28mm every time.. so I could have 24mm height with 4mm spacing, or 22mm with 6mm and so on, depending on how I cut the mask. Would that be correct?

Start point arrow? I assume you mean the marker on the inside, hence I made an image with the back opened. You can even see the serial number (150779), maybe anyone knows some sort of list or so which might help to locate the back in space and time.

View attachment 57460

sewarion

Click to expand...

Can you please take a picture of the insert, so that we can see the pressure plate? This is getting very interesting because a number of us who use the RZ system have never seen this particular type of back -- yet it appears to be manufacturer designed based on the labeling. Thanks!

Marc B. said:

Unless the seller has both the film-plane mask, and the focusing screen mask, (doubtful),
all you need do is mark the focusing screen with a marker to indicate the format lines.
Not much different then the markings for 6 X 9cm or 6 X 12cm roll film back
on a 4 X 5 inch GG...only smaller scale.

Click to expand...

I am noticing (I think) something curious from the pictures. First, as we know, the RZ does not have film masks of the type used by the FUJI 680 system. The film mask is provided by the outer housing of the film back, i.e., the part of the back that includes the ISO dial. OP already has this, as his first picture shows the "120 24 exp" label. Second, any finder mask only affects the user's ease of framing. AFAIK, finder masks have no role in masking light that strikes the film plane. This is what's interesting to me: from the pictures, OP appears to have everything necessary to use the back with proper spacing (although framing when composing shots would be challenging until he masks his focus screen in someway).

My conclusion so far: some prior owner of the back did not realize what they had and tried to "fix" the back but in doing so damaged it and now the spacing is off.

tnabbott said:

Can you please take a picture of the insert, so that we can see the pressure plate? This is getting very interesting because a number of us who use the RZ system have never seen this particular type of back -- yet it appears to be manufacturer designed based on the labeling. Thanks!

Click to expand...

The pressure plate, looks large/normal sized to me (aren't the pressure plates identical for all formats?):

tnabbott said:

I am noticing (I think) something curious from the pictures. First, as we know, the RZ does not have film masks of the type used by the FUJI 680 system. The film mask is provided by the outer housing of the film back, i.e., the part of the back that includes the ISO dial. OP already has this, as his first picture shows the "120 24 exp" label. Second, any finder mask only affects the user's ease of framing. AFAIK, finder masks have no role in masking light that strikes the film plane. This is what's interesting to me: from the pictures, OP appears to have everything necessary to use the back with proper spacing (although framing when composing shots would be challenging until he masks his focus screen in someway).

My conclusion so far: some prior owner of the back did not realize what they had and tried to "fix" the back but in doing so damaged it and now the spacing is off.

Click to expand...

I noticed that there are empty holes for screws, 2 on each side. Maybe this is where the correct (or any other) mask would be / had been attached. My regular 120 back is loaded, so I can't check it on there atm.



sewarion

edit: I talked to the dealer who sold me my regular back about the 'freak back'. He also told me that he had never heard of a thing like that ever, and he also checked the shop's computer archive on every RZ/RB back they ever sold: nothing even remotely similar.