A12 Film Back - Leak and movement against the camera body

[neil_guthrie]

<p>I recently changed the light seals on the A12 filmback on my 503cx and ran two films through it which were perfect.<br>

Exposures have previously been fine and a bit of the light seal came off so it needed to be changed<br>

After checking these 2 films were ok after changing the seal, I took the camera on a trip and ran another 13 films through it.<br>

11 of these films have a number of shots on them (between 2-3 to 8 images per film) where there are light marks on the right of the image running from top to bottom.<br>

This is shown in the image below. <br>

This can also been seen on the negative and there is also a bit of dark banding at the top and bottom edge of the negative for about 2/3 of it from left to right<br>

http://www.pbase.com/neilguthrie/image/159627691<br>

http://www.pbase.com/neilguthrie/image/159627694<br>

The films were developed by a professional lab<br>

When i got the negatives back and saw this, I took the lens off in a dark room, took the dark slide out and shone a torch into the dark slide insert to see if there was light coming in.<br>

There was a small amount of light entering so I took the film back off and then further tightened the screws holding the seal and checked again.<br>

It seemed ok and no more light was entering.<br>

I haven't checked a film again yet.<br>

I also have some movement of the film back against the body. Is there any way to tighten this?<br>

Would the banding at the edges on the negative be caused by light entering or can the movement between the camera body and film back also cause a problem with light entering or is it something else?<br>

Thanks for assistance<br>

Neil</p>

[savagesax]

Hi Neil,

 

The film backs always have some play in them, but the question is how much movement is too much? Also

how much wear is on the body, where the back connects to the body? The bottom part of the camera body.

There's a plate there. Can you take a picture of it? I don't think it's the plate on the body. They usually last for

decades.

 

From looking at the photo's above it looks like whoever did the seal replacement may have had a defective

seal. If it was my camera, I'd redo the seals and also change the dark slide. The dark slides get damaged

easily sometimes. For about $20 to $30, whatever the present cost is, it's worth having a perfect dark slide.

When I shot with Blads I'd change the dark slides often, whenever they got bent. A minor bend/fold is usually

OK. Depends on the location of the bend. So they don't always have to be in new condition.

 

However, there could be more to the problem and the seals are fine, but in my opinion it's unlikely that

something else is wrong, such as the camera body.

 

I need more information. Did you replace the seals yourself or did a repair shop? These seals are kind of an

interesting material. A repair shop could have used seals that were too thin or something, so was this a

Hasselblad repair shop? If the seals were too thick, the repair shop didn't use true Hasselblad seals, well the

dark slide could have ripped the rubber.

 

Last question for now is what shape is the dark slide in? Any bends, sharp edges? The reasons for asking

about the condition is dark slides can damage your seals, even if the seals are new. A bent dark slide can

create havic. It would also help if you could include a photo of your dark slide.

 

Kindly post a bit more information! As I've already said, I'd replace the seals again and if needed replace the

dark slide. Your problems should be solved. Good luck! bob

[neil_guthrie]

<p>Hi Bob<br>

Thanks for your help. <br>

Have posted some images of the body and dark slide. <br>

http://www.pbase.com/neilguthrie/hasselblad_<br>

I changed the seals myself as the previous mylar seal had fragmented and a bit had broken off.<br>

I got them from the guy in the US on ebay (blackbird71) who a lot of folks seem to use and these should be okay. I have a few more as spare seal sets so could change again.<br>

The fact that i had shot two films after changing the seal and this was okay had given me some comfort. <br>

I think perhaps, in retrospect, that I should have checked the further tightness on the screws on the seal after shooting a few films, although I thought I'd tightened them to approx same level as they were previously.<br>

The dark slide is straight with no bends or sharp edges and the film back has matching numbers.<br>

If the seal screws weren't fully tightened, putting the dark seal in and out might have allowed light in.<br>

There was definitely a difference in the reduction of light entering the body through the dark slide gap in the darkroom after I tightened the screws. <br>

I bought the camera in Japan approx 7 months ago so it is in good condition and have put approx 10+ films through it.<br>

The movement between the back and body is from side to side only.<br>

It would be good to know that I can rely on it for important shots to get a whole film exposed ok.<br>

I did still have lots of nice shots from my recent trip, but always take a lot of time and care in setting up shots, so its a bit frustrating to have found an issue when i got the films developed.<br>

Amazing camera though and images have a lovely quality different to a digital SLR and worth the trouble!</p>

<p> </p>

[savagesax]

He's a good guy. He lives up the road from me. First name is Dick. I'd order another set from him and

perhaps send him a message about the situation. I'm sure he will respond. He made a living for many years

buying, fixing, completely overhauling them and selling 1000's of hasselblads. If you don't hear from him let me

know and I will forward you his email address. Feel free in using my name. I've known him for about 30 years

or so.

 

The camera movement kind of sounds OK. After looking at the pictures, the body looks like it's fine. So I'd try

the light traps again. He also sells manuals for the assorted parts of the camera, such as the film back. He's

written the manuals so well that it's pretty hard to mess something up. You may wish to ask him about the

manual for the magazine. He shows you how to fix other problems that sometimes go wrong with the backs.

 

When you load the film then close the film loader, does it fit tight in the magazine? I'm wondering if it was

dropped at one point and something is slightly out of alignment. Probably not, Just a thought. I still think

replacing the traps is the answer. Anyway, he's a nice guy to get to know.

[Rob F.]

<p>There is a gear in the film back that is advanced by a corresponding device in the camera body. When the gear in the back gets out of alignment, it will cause the back to be kicked away from the body by a small distance--just enough to produce a light leak. This means it is time to get a CLA done on the back. If any light seals need replacement, that can be done at the same time.</p>