!@#^$#@% Bellows Flare-------Or Is It???

Hello all.

I have been wondering about this problem for some time and have

decided that I would pose some questions about it before I continued

with a camera that I am trying to build.

I have an old, highly abused Empire State 11x14 and a bellows

from a process camera that is about 14"x17" at the rear opening. I

thought that if I put the 11x14 back on this bigger bellows then I

could get rid of the problem with "bellows flare" for good. But in

looking at the way cameras are made I am not sure that this larger

bellows will solve the problem. It seems that the increased

negative density is about the same on all four sides of the negative

(when its there). If that is indeed the case then it must not be the

bellows that is causing the increased density. On 11x14 with the

back in the horizontal position there is more distance from the

bellows to the top and bottom of the film than there is at the

sides. So it seems that there would be more density at the sides

than at the top and bottom. This leads me to wonder if the problem

is really the camera back itself. The image opening at the camera

back where the film holder rests is fairly thick on most wooden

cameras and no matter how black it is, if there is enough light

striking it then it will reflect onto the film edges with roughly

the same density all the way around, except where enough movements

have been used to cause less reflection on one or more sides.

If the camera back is the real cause of �bellows flare� can I get

rid of it by putting a bevel on the camera back? If that edge that

is closest to the film is as thin as possible then it seems that the

problem would be solved. But how much bevel would be needed and at

what angle?

I would appreciate any thoughts on this before I start cutting

the backs of my cameras with my pocket knife or something.

Thanks, David

You never mentioned development on the negative...

 

Is there any chance that the increased density on the negative edges could be a result of non-uniform development?

Try using a compendium lens hood. That will keep excess light out of the camera, and thus reduce flare from the camera interior. But I second the idea about processing, too.

David,

Good suggestions have allready been offered.

 

Let me just add. Take the camera back off the camera and insert a holder. Standards way back when weren't all that standard. Make sure the ridge on the holder fits into the slot on the camrea back. I have had to make small modifications before. The spring back on my Korona 11x14 didn't seem to hold the CFH tight enough to suit me. So I replaced it with a Kodak spring back that I had pick up at a swap meet.

 

Have fun,

George Losse

Hello, and thanks for your quick responces. I believe that I can rule out processing as the culpret at this point. I also believe that a lens hood would help my images, but several of the lenses that I use are process lenses in barrels. My shutter is a plastic roll film developing tank, so I haven't been able to figure out how to use a hood with this "cup" shutter. Plus, some of these lenses have a big circle even at infinity so there is a lot of light that is bouncing around inside the camera. Don't you think that it could be the wood that the film holder rests on?????

David, have you tried shining a small pen light through the front and see how it reflects on the GG? I have the same problem that George had, the tension bars for my Korona are really weak and do not hold the holder in place tightly so I place the horse blanket on top the back when I take pics.

I think this is a mechanical problem and not bellows flare, I see very little flare on my 8x10 or 12x20 and I doubt since you have a bigger area that that is the problem.

I would put a holder and check for light leaks around the holder before I mess with the back or the bellows. Perhaps your holder is not being held tight enough.

Since you are not really sure that the problem is flare you need to

go through all of the other reasons that the film could be fogged,

Flare would not be my first suspect. My order of possible causes,

in order of probability, is.

 

1. You have a light leak somewhere in the camera. It could be a

pinhole in the bellows, a problem with the way the holder fits in

the camera, a leak at the lensboard or where the lens board

attaches to the front standard, etc. To eliminate this possibility

follow the light in the camera method suggested by Jorge and,

with the bellows fully extended, look at the camera and bellows

from every possible ange for any sign of light.

 

2. A leak in the film holder. Most likely this would be at the baffle

end where the dark slides insert, but it could also be at the flap

end. To check you holders remove the dark slides and look back

up through the baffle, with your eye at the flap end of the holder,

at a very bright light. Scan across the entire area of the baffle

from left to right. If you see any light at all there is your problem.

 

3. Flare from internal reflections off the bellows, off wood in the

camera, or even off the film holders.

 

Sandy King

If its extra edge density on the neg I would say its development ie shaking the film in a try as opposed to lifting and turning it. Bellows flare is usually even all over the film and not just at the edges. It shows up as fog from my experience. Could you scan a neg and invert it so we could have a peep at the problem? Or make a quick contact?

 

CP Goerz.

Take out the gg and point the camera at a bright wall. Set the distances where it would focus normally. Now, look in the back at all angles and see what the light is bouncing off of. Remember that even a dull black surface will become an excellent reflector if the angle is shallow enough. When you think you know what the problem is, draw a side view with a ray trace from the lens to the offending object. Angle of incidence equals angle of reflection, so decide how to cut, bevel, or whatever, to fix it.

Many good suggestions. One other. Make sure the wood the

holder sits on is painted matte black. There is a special paint I

got a long time ago--forget exactly what it was called--that was

dead flat and absorbed all light. It is much more absorbant than

Rust-Oleum matte black. It is used in solar heating applications.

 

Also, ALWAYS use a lens shade. Use the type with set

screws--you can get one hood to fit on many lenses, each with a

different diameter. Details about this are in a thread somewhere

on the Azo Forum on my web site.

 

Michael A. Smith

<i>David, have you tried shining a small pen light through the front and see how it reflects on the GG?<BR><BR>

 

-- Jorge Gasteazoro , August 06, 2003; 03:35 P.M. Eastern</i><BR><BR><b>The snooping around with light/flashlight is a good thing to do.</b> ; very low tech; and often finds overlooked internal patches with too refective tape; holes etc. Also check for bellows light leaks; these can be patched with Artists "black Liquitex"

And FWIW, have you tried a different batch of film?