what's wrong with my bronica back?

zenza · May 2, 2009

I've search a little for a topic like this and couldn't find anything. I'm sure it's a common problem but at the same time I don't know what it is. I've got one bronica back for colour and one for b+w. The one which I shoot b+w in keeps giving these weird flares, sometimes entire gray bars through the frame. Is this a light leak or a winding problem? I've posted a photo as an example of what's happening:

Thanks for any help

paul_c5x4 · May 2, 2009

Yes, it is indeed a light leak - If you look at the foam around the top of the back where the door meets the locking mechanism, you may well find it gummy or ripped up. There are other thin strips of foam around the opening that may have also turned to mush.

I managed to find some from an ebay seller by the name of interslice - Give him a call, and I'm sure he can send you a pack of foam for peanuts.

DWThomas · May 2, 2009

A while back I placed some shots of the offending areas of an SQ series back near the bottom of this page. That might help if you decide to fix it yourself. In the light leak example on that page, the seal along the opening edge was almost completely missing. Yours is apparently just beginning to go. The problem seals are a foam that reverts to gunk.

DaveT

zenza · May 2, 2009

ah, many thanks to both of you. looks like I'll have to check out some new foam seals then.

vdonovan · May 2, 2009

Hey zenza, that's a real nice pic. You're putting your Bronica to good use.

If you're going to shoot Bronica, you may as well learn how to repair the light seals. I did exactly what the gentlemen above recommend: found Interslice, bought some seal material, fixed my backs. Dave Thomas's web page, which he links above, was very helpful. Doesn't take long nor require much skill nor cost much money to fix the light seals.

The upside: now I can buy UGLY grade backs from KEH.COM for ten or twelve bucks. Usually the only thing wrong with them is the light seals.

zenza · May 3, 2009

Yep, I ordered my little kit. And thanks for the comments on the photo. I had never thought about the UG backs on Keh...good call. Thanks again everyone.

Jay Decker · May 3, 2009

DWThomas said:
A while back I placed some shots of the offending areas of an SQ series back near the bottom of this page. That might help if you decide to fix it yourself. In the light leak example on that page, the seal along the opening edge was almost completely missing. Yours is apparently just beginning to go. The problem seals are a foam that reverts to gunk.

DaveT

Dave - thank you for the information. I have a question for you regarding removing the old foam gunk, what is your method for getting it off?

Thanks,

Jay

DWThomas · May 3, 2009

Jay Decker said:
Dave - thank you for the information. I have a question for you regarding removing the old foam gunk, what is your method for getting it off?

One of the items in the kit of material from Jon Goodman is a small bamboo stick with a shaped end that works for scraping down into narrow grooves. I'm sure something similar could be improvised. A bit of naptha (lighter fluid) usually works to soften and clean off most of the adhesives that seem to be in use the last few decades. Naturally, such solvents should be used with caution, not slathering them on spots where they may run into strange places. Also, ventilation could be good, and sparks or flame in close proximity could be extremely bad! :rolleyes:

Hope that helps,

DaveT

Shangheye · May 3, 2009

Be judicious about the size of the foam you replace. Too big is just as bad as too small. Then go out and test it. I still have a back I haven't got quite right (just replaced it the third time). If the foam is too wide, it will deform when the back is closed and stay that way after you open the back. The result is when you use it again, the deformation still causes a light leak. Rgds, Kal

zenza · May 3, 2009

Ugh...today my other back crapped out on me. I guess it's dirty digi for a while now...gotta love film.

Kal - are there instructions with the kit that show you how to get the foam right? what exactly should I be expecting when it comes time to replace the foam, do I have to cut the strips out myself, measure them, etc?

DWThomas · May 3, 2009

The kit from Jon Goodman ("Interslice") has several different thicknesses of foam and also some cloth. Some of the material is precut to commonly used widths, leaving you to cut lengths. There are multiple pieces on a slippery backing paper, just as with adhesive labels and the like. Jon has instructions for a number of common camera items on line, but as of late 2006 he did not have any for the Bronica backs. There is nothing subtle about the foam thickness he supplies -- it's 1.0, 1.5 and 2 mm thick if I remember right. As mentioned earlier, you don't want so thick it wads up in big chunks, but I think there is a fair amount of tolerance. (Plus there's enough stuff in the kit to do a dozen backs, so you can experiment a bit if need be.

DaveT

Shangheye · May 4, 2009

No instructions I am afraid, though Dave T may be able to give you some idea, and his site on pbase is very informative. The existing foam strips are a good guide to size. The kit comes with instructions on how to cut etc and is very easy to use...don't forget to lick the sticky side before locating the foam...that gives you time to put in the right place before it starts to stick. I have three backs. One is perfect, the other seems repaired (though the real test is on a VERY sunny day, and I have not had the chance to test that) and the third I am waiting on the film. It takes not more than half an hour to do a back completely...you will now if you cut the foams too wide, because when you open the back after closing, you will see it is quite deformed. The difficulty is knowing when they are too narrow.....I do it by removing the insert and closing the back to check if where the back closes the foam meets correctly at the locking mechanism..ie only slightly compresses. On the bright side this happens with all makes and all backs..even Hassys...not a function of the camera brand. Rgds, Kal

Lee J · May 4, 2009

Those might actually be down to flash flare from the Bronica fisheye - it suffers from it really bad when you get the flashes too close to the edge of the frame and is very common. It ruined at least a third of my shots when I used to use it for skate shots with off camera lighting. Did you crop the edge of the frame slightly? The reason that I don't think they're light leaks:

- You were obviously shooting in dark conditions, do you get this on all your exposures in the same place, especially in lighter conditions?
- Light leaks tend to either be sharp streaks, or follow difraction patterns, this doesn't look too much like that. It just looks like the typical Bronica fisheye flare, do you see this in shots taken without the fisheye?

If you don't already have one, I would suggest investing in a polaroid back when shooting with the fisheye and off camera lighting, it's very useful for checking the flashes aren't too close.

zenza · May 4, 2009

It very well could be flash flare but I get it on all of my other shots from this back. Sometimes it's full bars through the frame, sometimes it's just those pointy ones.

Shangheye · May 5, 2009

The "mirroring" effect is definitely the light leak...and it is as Dave mentions the seal where the back meets at the top that is the culprit. The light leaks on to the film frame BEFORE it wound on to be exposed. hence sometimes if you are shooting quickly some appear to be free of a light leak. That is because you wound the film on quickly before the preceeding frame has a chance to be fogged. If the film has not been wound on for a while, then the next frame has a high light leakage. That is why the leak can sometimes be absent or appear differently from frame to frame. K

DWThomas · May 5, 2009

Shangheye said:
The light leaks on to the film frame BEFORE it wound on to be exposed. hence sometimes if you are shooting quickly some appear to be free of a light leak. That is because you wound the film on quickly before the preceeding frame has a chance to be fogged.

This is an important note, probably in diagnosing any light leak. The film travels around a bit before and after the spot where it is exposed. The scan of a badly zapped negative ("Oh my back!") on my gallery page represents what eleven of the twelve frames looked like, to a varying degree. The first frame, taken at that same outdoor location, was fine and printable. I loaded that camera in a relatively low light level indoors at home and had wound it to have frame 1 ready to go, so it got to the masked exposure area unscathed.

One also needs to think about the image being inverted on the film when trying to work backwards from the light-struck spot to the camera body leak.

I imagine buying and using old cameras will help all of us improve our diagnostic skills!

DaveT

zenza · May 5, 2009

Shangheye, that's very useful, thanks a lot. I'll be keeping that in mind when I'm out shooting next time.

I've decided that I'm going to keep using this back until the foam gets here, I'm just going to tape the back like crazy with black electrical tape. Has anyone ever tried this out before? It's going to be janky, I don't doubt that for a second, I just hope it works.

Shangheye · May 5, 2009

Yes, I have done it and it works. You only really need to tape the top since that is the most likely location for the leak. That means you only need to remove that to unload/load. I also still tape them up on very bright days and serious work (commercial) since I can not afford a failure. Kal

what's wrong with my bronica back?

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