Help Please! RZ+Polaroid Back. First photo OK, rest white :(

[MatthewOsbornePhotography]

Hi guys.

Help please!

I have a Mamiya RZ + RZ Polaroid film back. I tried a pack of Fuji FP3000B first. The first photo was OK (below) and rest of the pack came out white (completely over exposed) even stopping down to F22 to try to get a black underexposed image.


Mamiya RZ Polaroid by MatthewOsbornePhotography - Leica Photographer, on Flickr

Yesterday I tried a pack of Fuji FP100C colour instant film. I metered the light before hand, cocked the shutter lifted out the dark slide and took the shot. It came out pretty good so was pleased. I then tried again now the camera was working and got a completely white photo with same settings and 'developing' time. I thought I mus thave done something wrong so stopped down the lens to get a darker image but again completely white.

It seems strange that it has happened with 2 different film packs on 2 different days under different conditions.

I don't want to keep throwing money away on film so help would be much appreciated.

Thanks

Matt

[GeorgeSalt]

The first shot of a fresh pack is working, but subsequent shots are being over-exposed? The only differences with the first shot is that it has the paper strip removed in front of it and it's the first shot taken after freshly mounting the back.

- and it's definitely over-exposure? I get caught out by the dark slide on my P-backs (RB67) from time-to-time because they're the only backs I have that don't interlock. I've stitched 20cm of red ribbon to the dark slide handle because I've done it that often.

I'm really struggling to see how one shot can be ok, but the second could fail - but I do know from my RB67 that the Mamiyas have some very inventive mechanical failure modes if you don't get everything in sequence.

If you remove the back, replace it.. sacrifice the first frame (i.e. pull it without taking the shot) does the next shot work? That's effectively duplicating the sequence of a fresh pack in the middle of the pack. But I still can't see a failure mode that would allow the first shot to be ok.

[RSalles]

Mathiew,

Take some shots without the back looking directly to the curtain. Look if the curtain reacts synced to the shooting speed, if it remains open when it's is supposed to close after the shot, etc. I thinking on it 'cause you didn't mention if with normal negative film the shutter was ok at every speed. Also take a look at the lens, it's supposed that the lens remains wide open until the shot, when it closes to the aperture you've done... Try it out several times to make sure that's not a camera issue instead of film,


HTH,

Renato

[MatthewOsbornePhotography]

Thanks guys.

OK so more information, I have shoot many rolls with the camera & lens setup on roll film with no issues.

I have tried 2 new packs of film and the first shot exposes OK but the rest overexposed (blown out all white).

Dark slide was removed but yes it is easy to forget!

If I look how the RZ film back mounts it is not a a flush fit to the camera back as one of the lugs (that should fit into the 4 round holes on the RZ camera body where it rotates does not leaving a small gap. My only thought is maybe the first photo is covered so protected then I take the shot and OK. The dark slide does not go straight back in meaning light leaks onto this photo so when do take the shot is overexposed.

I will tape up the gap and tried that AND try taking 2 shots almost back to back so to give light less chance to hit the film on the second shot.


Thanks

Determined to get it working as the results can be amazing!