Bronica SQA light leaks + splotches. What's causing them?

[Pandysloo]

I just got my second roll back shot with my Bronica SQ-A. The first roll was completely free of light leaks, but the second one was full of them. For the first roll I shoot entirely on a tripod, and advanced to the next frame before reinserting the dark slide. For the second roll, I shot entirely handheld (except for 1 tripod shot). Because I was fumbling with the camera, I inserted the dark slide before advancing the crank with each shot, and the one tripod shot where I wound the film before inserting the slide is the one shot on the roll without a light leak. Could my sloppy darkslide handling have caused the leak? Is there a way to test for leaks without burning through film? Also, is there any reason to use a dark slide if I'm not changing out backs?



I also noticed black splotches on some of the frames. Does anyone know what this could possibly be?

 

[lxdude]

There is no need to use a dark slide if you are not changing out backs in mid-roll. You can use it to keep dust out of a loaded back off the camera before or after the roll is shot. Inserting/removing the dark slide should not cause a leak, but it can if the light seal is worn or damaged. Bronica recommends not carrying the camera with the dark slide in place because it defeats the interlock and the back can come off if the release button is accidentally depressed. Contact Jon Goodman (who is here on APUG) for one of his excellent light seal kits. In the meantime, don't use the dark slide and tape over the dark slide slot for extra security. You can change film by removing just the the insert to reload.

As to the blotches, clean the insert thoroughly with a alcohol on a Q-tip or light cloth like a microfiber cloth, and make sure to blow out any fibers afterward. That might help.

 

[Pandysloo]

Thanks that is helpful, but I'm not entirely clear. Are these leaks something that only occur in the dark slide slot, or do they occur on any crack on the film back? Would it be safe to assume its coming from the felt darkslide slot, or would I need to test it somehow to find the source? Sorry I'm new at this.

 

[lxdude]

The dark slide slot is the usual culprit. The other surfaces on the back and insert fit together without seals, so unless there is damage to the back or insert, the designed-in baffles will keep out light. Actually there are seals in the slots on the insert where the door on the back closes over the insert, but due to the depth of the slots light won't get past even if the seals are missing.

And welcome to APUG!

 

[Pandysloo]

So I opened it up and gave it an inspection. The black splotches were caused by the deteriorating seal at the top of the film back next to the ISO dial on top (is that what you were referring to as a seal that isn't neccessary?). It is pilly and covered in ink for some reason. I found ink splotches on the main rollers as well as the little silver rollers which I didn't even know existed until now. I didn't have any cotton swaps or alcohol, so I used warm water and a paper towel instead.

Could the leak be caused by this deteriorating seal? The light leaks were horizontal, so I don't see how it could be the cause. Took off the film back, took out the dark slide, and tried to shine a light through the dark slide slot in a dark room and I couldn't find any leaks, though I did find more foam pills in the slot clogging it up.

Is the seal kit from Mr. Goodman for this foam specifically, or is there another seal I'm overlooking?

 

[Usagi]

Hi,

I had similar light leak in one of my SQ-Ai backs. The cause was same seal.

I bought foam from http://www.aki-asahi.com/store/ and fixed leak.

There's was one good tutorial in the net, but I can't find it any more.

 

[Dave in Kansas]

I've had light leaks just like yours on my SQ-A. Your foam seals are bad and need to be replaced. You can get light leaks through the dark slide opening if those seals are bad too. On some backs, the plastic plate that mates with the body can crack, usually at the corners near the small screws.

Dave

 

[Daire Quinlan]

I had almost exactly those same light leaks, in exactly the same location. Seals around the latch I suspect were the culprit. They weren't decayed but they were squashed and worn looking. Replaced them all with some self-adhesive foam I also got from aki-asahi and the problem has disappeared.

 

[Pandysloo]

Thanks for you help everyone! I ordered a repair kit from aki-asahi. I will report back if I run into any more problems.

 

[lxdude]

So I opened it up and gave it an inspection. The black splotches were caused by the deteriorating seal at the top of the film back next to the ISO dial on top (is that what you were referring to as a seal that isn't neccessary?). It is pilly and covered in ink for some reason. I found ink splotches on the main rollers as well as the little silver rollers which I didn't even know existed until now. I didn't have any cotton swaps or alcohol, so I used warm water and a paper towel instead.

Could the leak be caused by this deteriorating seal? The light leaks were horizontal, so I don't see how it could be the cause. Took off the film back, took out the dark slide, and tried to shine a light through the dark slide slot in a dark room and I couldn't find any leaks, though I did find more foam pills in the slot clogging it up.

Is the seal kit from Mr. Goodman for this foam specifically, or is there another seal I'm overlooking?

OOOPS!:eek:
I really shouldn't try to give others advice after a long and boisterous Halloween night.
Especially going from memory, as I don't have a film back handy.

I think that seal is necessary, though light leaks are still unlikely IMO without it. I don't think that's the cause of the leak-it looks to me like the dark slide slot is the cause of the streaks. The other seals I was talking about are inside the grooves on the back of the insert where the edges of the rear (hinged) half of the film back close over it. There is also a necessary seal made of felt on the bottom of the film back next to the hinge, which lasts longer than foam.

That deteriorated seal is foam, which has broken down from age. It causes that inky, sticky mess that I should have recognized as being from the seal, having dealt with it numerous times myself. It was widely used by manufacturers. Jon Goodman's kit contains a wooden tool to scrape it out, and then you need a little lighter fluid (naptha) and a lintless cloth to get it all off. Alcohol works, but I like lighter fluid. Using either on the rollers will ensure you got it all. I guess a paper towel would work as a cloth; just check for fibers afterward. Jon's kit cost me I think $10 a few years ago, and it contains all the seals needed for one back, and instructions. His kits are very high quality.

I have not used the kit from Aki-Asahi, but they have a good reputation for their camera leatherette replacement kits.

 

[lxdude]

There's was one good tutorial in the net, but I can't find it any more.

Maybe the one at Kyphoto. They have Jon Goodman's instructions there. Google kyphoto and you will see the link for Jon Goodman's seal info.

 

[DWThomas]

Yes, that horizontal line is likely the seal where the back opens, up toward the ISO dial/latch.

See my PBase SQ-A page, toward the bottom. The shot labeled "Oh my Back!" is from a back with practically no seal left. It's the film coming off the supply spool that gets hit, not the film in place at the frame mask, so it's appearance can be variable depending on ambient light and how fast you wind through frames.

The good news is it fixable!

(Late catching up with this, having no power at home since Monday night.)

 

[ParkerSmithPhoto]

So I opened it up and gave it an inspection. The black splotches were caused by the deteriorating seal at the top of the film back next to the ISO dial on top

Indeed. I had the same problem and got through many years by making a band out of black elastic and placing it over the back like a cuff! It was pretty low tech but it worked.

I finally sent it off to Koh's Camera and he fixed it perfect for a crummy $20. Wish I hadn't waited so long. He's the Bronica guy.

 

[Pandysloo]

Yes, that horizontal line is likely the seal where the back opens, up toward the ISO dial/latch.

See my PBase SQ-A page, toward the bottom.

Just repaired my back using your page as a guide. Super helpful stuff! I will report back once I run a roll through it...

 

[Pandysloo]

Update: I fixed the light leaks for the most part, but since 95% of my shooting is done in cloudy/rainy weather, I figure it wasn't much of a test.

I recently did a lot of shooting in intense sunlight and found a good portion of my negs ruined by light leaks. This is just one of many photos afflicted, all of them with a leak of the same intensity and location.



I'm trying to figure out where to locate this particular leak so I can go in and add some more foam. The image is flipped upside-down, correct? So based on this the leak is coming from the center, spanning downwards on the left side of the back?

 

[DWThomas]

Hmm. I wonder if the seal across the hinge part of the back is gone/deteriorated? (#3 in this shot)

I think the leak is stronger toward the right side, viewing the camera from the back when the film is upside down -- but it could just mean the sun was on that side!

These things can be weird, the actual leak may be near the supply or take-up spool and not striking the actual mask frame area. In such a case, it's either the frame before, or the frame after the shot that gets light struck. My hands-on personal experience with these problems is still fairly limited (thank the Flying Spaghetti Monster!) so it's difficult to speculate on the full range of possibilities.

Another dubious thought is that possibly the light baffle behind the mirror in the body isn't closing all the way, and light comes in through the lens and around the sides of the mirror. As I type that it sounds far fetched, but obviously something is not in factory spec.

An additional vague possibility (based on analysis, not experience! ) is that the back isn't seating tightly due to the little retaining hooks being worn or loose or something.

I suppose black (gaffers') tape could be carefully applied to help in isolating the light path. If all the back attachment and closure stuff is taped and it still happens, that might suggest the light baffle. If the joint between the back and the body is taped and you still get it, it pretty much has to be one of the long seals at the top or bottom.

You could also plan some real test cases -- put the camera in the sun with a lens cap on and pretend to do some exposures, change the angle of the light hitting it, etc.

That's what passes for my thinking -- no charge!

 

[DWThomas]

And the next day ...

I've been thinking (smell the smoke!) the fact that there appears to be light struck area on the film rebate pretty much means it's a seal problem. The frame mask is between the film and the body shutter, and even the dark slide and the back to body joint. The rebate is more open to exposure between the spools and the insert rollers.

There -- how's that for profound pronouncement!

They are really neat and capable cameras, but the back light seals appear to be a weak spot. And of course virtually any backs around are at least a dozen years old -- and maybe thirty!

 

[Pandysloo]

What exactly do you mean by "rebate?"

 

[DWThomas]

What exactly do you mean by "rebate?"

The edges of the film with the manufacturer's markings on them; that is, outside the picture frame area. That portion is normally protected by the mask when the actual frame is exposed, so if it is light struck, the light must be catching it when another frame is lined up for exposure.

 

[Pandysloo]

So you think the leak can be located somewhere around the spool of the back, and not the darkslide slot? That certainly helps!

What type of cheap film should I run some tests with? If this was 35mm I could just run to the drug store and grab something cheap...

 

[DWThomas]

I would expect a darkslide slot leak would be some sort of wispy smear that cuts off short of the film edge, and maybe even angled depending on the external light conditions. (But I am working more on analysis than experience here! )


As to film, cheap is a relative term! The faster the film, the more sensitive the test, but it's probably silly to go for 1600 or more. I would probably opt for an ISO 400 like TriX, Tmax400, HP5, or Delta 400. If you have to send out (and are in the US) one of the Freestyle films -- maybe Arista EDU Ultra 400 -- that's pretty inexpensive.

Hope you find it soon; that can be pretty frustrating.

 

[Alex Muir]

Hi. I am interested in this thread because I am also an SQ user. I bought two extra backs to use. One of them had badly decayed seals. I replaced them all with materials I bought from an English supplier I found on the web. I have also used Jon Goodmans products which are excellent. The thing I realised was that there are a large number of seals on these backs, any of which could cause a problem. It wasn't difficult, but more time-consuming than doing a 35mm camera. I would recomend that you get another back in good condition and try that. You can then spend time fixing the original. If that isn't an option, you could apply tape to all joints, including back to body, and darkslide slot, then take a test roll removing one piece of tape per frame to identify which joint/opening is the problem. Alex

 

[Pandysloo]

I think I may have found the problem? On the back left side, part of it is warped, evidenced by the non-parallel lines. When I push on it, it flexes inward, unlike the opposing side, which is both parallel and snug. Could a leak here lead to the examples I posted? I'm unsure because the film is rolled up in the rear of the back, not "open" like it is closer to the dark slide.

 

[DWThomas]

My gut sense is that may not be it, but it would depend on whether light can get far enough past there to bounce around inside. You could put some black tape over that section to test out the theory. That side section is part of the insert. I looked at one of my backs that is handy. On mine there is a rib horizontal across the interior of the insert, between the film rolls, that provides a gusset which potentially makes that side plate rather rigid.

That leaves me to wonder if maybe there could be some sort of structural damage to your insert that is the root of your problem. Are there any cracks in that internal portion?

But then, the side section appears to be a thin outer cover over the inner injection molded part, so I suppose the outer cover might be bowed away from the inner part with an air space between. That may or may not be a problem, hence the encouragement to use tape and test.

The closure around that portion of the back does not use foam seals, just a sort of labyrinth arrangement where a rib on the insert goes into a channel along the back shell which doesn't seem to be very tight, suggesting it's not critical.

(This is another area where some spare modules to interchange could be handy for diagnosis.)

 

[donkee]

When the postman delivered my Bronica backs first thing I did was checkout the seals and brush out any debris. Next I load up some arista 120 from Freestyle (cheap for testing) then I put the back on the camera and rotate the camera under direct sunlight then start taking some test shots. Any light leaks will show up. I do the same with any new camera.

The only one I had a problem with seemed to have a bent cover or messed up latch. When I closed/latched the cover it would pop back out a little. It created light leaks that were really close to what you have been seeing.