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jetcode
30-Apr-2008, 16:51
4x10 film (color and B/W) same fog pattern in same location on evey neg shot with 360mm Sironar N, no shade, not in direct sunlight. Rotary tube processed film is fine for other lens so it's not the processing and not the film as it appears exactly the same on all sheets color or black and white. This image was shot from the shade.

Scott Kathe
30-Apr-2008, 17:11
Maybe your lens board is not seated properly and you have a light leak along the side?

Scott

alec4444
30-Apr-2008, 17:24
Yikes! Sorta takes the "Elite" out of your Scans.... Sorry, that was irresistible.... :o


Maybe your lens board is not seated properly and you have a light leak along the side?

Scott

...which is easy to check. Close the lens, take the back off and point the camera at a bright light source. If you see light, you see problem.

I don't think it's that, though. Did you notice how the sky seems to appear fine? Is that upper quadrant always ok, or did it just fail on this shot?

--A

Kirk Gittings
30-Apr-2008, 17:31
"Did you notice how the sky seems to appear fine? Is that upper quadrant always ok, or did it just fail on this shot?"

I don't think you can assume that because the texture of the sky may be masking the problem. I would do some tests looking for light leaks withe the lens board, separation of the bellows, fit of the back and fit of the film holder.

Joe did you process both the color and the b&w in the rotary drum?

If this was my film, with some development procedures (certain tanks), I would also check for insufficient developer quantity, because in a tank where the film sits upright, the lighter areas might reflect lack of developer and the darker area right below it, increased agitation at the the dev. top level. Does that make any sense? I have seen something like this before and this was the issue.

jetcode
30-Apr-2008, 18:08
"Did you notice how the sky seems to appear fine? Is that upper quadrant always ok, or did it just fail on this shot?"

I don't think you can assume that because the texture of the sky may be masking the problem. I would do some tests looking for light leaks withe the lens board, separation of the bellows, fit of the back and fit of the film holder.

Joe did you process both the color and the b&w in the rotary drum?

If this was my film, with some development procedures (certain tanks), I would also check for insufficient developer quantity, because in a tank where the film sits upright, the lighter areas might reflect lack of developer and the darker area right below it, increased agitation at the the dev. top level. Does that make any sense? I have seen something like this before and this was the issue.


I've processed the same B/W film using a different lens and the effect is not there. The color film was developed elsewhere. I think it is some form of fogging die to light leak at the lens board. This lens is massive and barely fits. The camera is brand new and so far only the 360 has produced these results.

Kirk Gittings
30-Apr-2008, 18:48
What are your other lens lengths? Sometimes a wide lens shifted extreme will show a light leak problem that a long lens won't and vice versa. Bellows leaks in particular are that way.

Bruce Watson
30-Apr-2008, 18:53
4x10 film (color and B/W) same fog pattern in same location on evey neg shot with 360mm Sironar N, no shade, not in direct sunlight. Rotary tube processed film is fine for other lens so it's not the processing and not the film as it appears exactly the same on all sheets color or black and white. This image was shot from the shade.

It's not a light leak. A light leak results in increased exposure, yes? This is decreased exposure. Or more properly decreased density. But you've already ruled out film and processing, so that leaves exposure.

So I'm thinking that something is blocking (or at least interfering with) light coming from the lens from reaching the film. Could it be a pleat from the bellows up at the lens end -- intruding into the light path just behind the lens? This would be consistent with a really large rear element and the long bellows extension with a long lens -- bellows sagging on one side maybe?

Ole Tjugen
30-Apr-2008, 18:59
Can you process two films together, taking care to turn one "upside down" compared to the other (i.e. one with the notch top right, one bottom left)? That will show whether the problem is in exposure or processing.

jetcode
30-Apr-2008, 19:27
What are your other lens lengths? Sometimes a wide lens shifted extreme will show a light leak problem that a long lens won't and vice versa. Bellows leaks in particular are that way.

I have a 150XL, 240 caltar, 480 ronar

jetcode
30-Apr-2008, 19:28
It's not a light leak. A light leak results in increased exposure, yes? This is decreased exposure. Or more properly decreased density. But you've already ruled out film and processing, so that leaves exposure.

So I'm thinking that something is blocking (or at least interfering with) light coming from the lens from reaching the film. Could it be a pleat from the bellows up at the lens end -- intruding into the light path just behind the lens? This would be consistent with a really large rear element and the long bellows extension with a long lens -- bellows sagging on one side maybe?

bruce, what's odd is that the part that appears to be underexposed may actually be properly expose and the rest of the film slightly fogged, it sort of looks that way on the film even though it is not fogged much except at the bar

jetcode
30-Apr-2008, 19:32
Can you process two films together, taking care to turn one "upside down" compared to the other (i.e. one with the notch top right, one bottom left)? That will show whether the problem is in exposure or processing.

In one session I processed several sheets shot with the 360 and several with the 240. The 240 sheets do not have this effect, nothing changed on the camera, back, or film holders.

Donald Miller
30-Apr-2008, 19:42
Joe, Is this shot with a dedicated 4X10 holder or an 8X10 using a split dark slide? On which end of the negative does the decreased density appear?

jetcode
30-Apr-2008, 19:48
Joe, Is this shot with a dedicated 4X10 holder or an 8X10 using a split dark slide? On which end of the negative does the decreased density appear?

knowing that light enters by inverting the image left to right the defect is on the left side of a dedicated 4x10 holder (farthest from dark slide). I thought my back might generating the leak during the removal of the slide because it wasn't super tight and then I saw other images used by other lenses exposed under the same conditions.

N Dhananjay
30-Apr-2008, 21:13
It's not a light leak. A light leak results in increased exposure, yes? This is decreased exposure. Or more properly decreased density. But you've already ruled out film and processing, so that leaves exposure.

So I'm thinking that something is blocking (or at least interfering with) light coming from the lens from reaching the film. Could it be a pleat from the bellows up at the lens end -- intruding into the light path just behind the lens? This would be consistent with a really large rear element and the long bellows extension with a long lens -- bellows sagging on one side maybe?


I've had this problem once and I actually did trace it to a light leak (well, it was more of a slit or tear) close to the rear standard. The light sort of sprayed across the film sheet - the far end is the only area it did not get to. If it is something similar, the underexposed area is actually unfogged and the rest of the film was hit by stray light. The light leak theory is easy to test - take the camera into your darkroom, stick a holder in, fully extend the bellows and stick a flashlight inside and it should be easy to see any pinholes or light leak areas. It could certainly also be something intruding into the light path. You say you didn't use a shade - so barring your hand or something on the outside, it's likely to be a bellows pleat.

I'm a little foxed as to why it only shows up with this one lens - could be that the bellows is extended just right with that lens to how up the light leak or blocking pleat.

Cheers, DJ

Scott Kathe
1-May-2008, 05:05
Why don't you set up a shot and make an exposure then run some lightproof tape along the sides of the lensboard and make another exposure, then throw your dark cloth over the bellows and back of the camera and make an exposure. I would think it has to be either the lensboard, bellows or back.

Scott

Mike Castles
1-May-2008, 05:10
First thing I would try is to place a film holder in the back, close the lens off and place a flashlight inside - with the camera in the darkest room you have. Give your eyes a chance to adjust and I bet you find the problem if it is the back/bellows/lens board.

What seems odd to me is that strip of land that seems expose just fine, with what appears to be nothing on either side (top/bottom)

Jiri Vasina
1-May-2008, 05:27
It seems Bruce was not explicit enough in his statement and you are looking for a solution in the wrong direction. On the presented negative, the right part is lighter (brighter) than the rest of the image. It's a negative, therefore, when inverted to match the amount of light hitting the film, it would be darker - less light did indeed hit the film. So you must be looking for something blocking the path of light.

Starting from the lens (is there something on the lens?, something wrong with the shutter?), the most likely place being the bellows or frames holding the bellows (something protruding inside from the bellows, it would be on the left side of the camera), or something with the back of your camera (least likely, as it would show with other lenses too. And again, if the negative shown is correctly oriented, it would be something on the left side of the back). (you said you have excluded processing and film issues).

Hope this helps a bit.

Renato Tonelli
1-May-2008, 05:51
I think Bruce and Jiri are correct on this. I had a similar problem years ago with a 4x5 neg shot with a 90mm lens and a normal bellows. The bellows would scrunch in just enough, always on one side, blocking the light in an up-down stripe.

jetcode
1-May-2008, 06:11
Why don't you set up a shot and make an exposure then run some lightproof tape along the sides of the lensboard and make another exposure, then throw your dark cloth over the bellows and back of the camera and make an exposure. I would think it has to be either the lensboard, bellows or back.

Scott

I always shoot with a dark cloth over the rear standard opening on the right side to remove the film holder. I am suspecting it has to do with the weight of the lens on the front standard but for sure I am collecting ideas from contributers here.

Steve Hamley
1-May-2008, 06:31
You can eliminate the lens board issue by rotating the board 180 degrees. If the problem doesn't move to the other side of the frame, it isn't the board.

I'd also try a regular 8x10 back and see if the problem shows up with the different back.

Cheers,

Steve

Scott Kathe
1-May-2008, 06:41
It's not a light leak. A light leak results in increased exposure, yes? This is decreased exposure. Or more properly decreased density. But you've already ruled out film and processing, so that leaves exposure.

So I'm thinking that something is blocking (or at least interfering with) light coming from the lens from reaching the film. Could it be a pleat from the bellows up at the lens end -- intruding into the light path just behind the lens? This would be consistent with a really large rear element and the long bellows extension with a long lens -- bellows sagging on one side maybe?

Oops, definitely decreased density so not a light leak. Maybe when you hang your dark cloth on the camera it pulls the bellows in a horizontal direction and caused the difference in exposure you see.

Scott

jetcode
1-May-2008, 09:04
Oops, definitely decreased density so not a light leak. Maybe when you hang your dark cloth on the camera it pulls the bellows in a horizontal direction and caused the difference in exposure you see.

Scott

actually I have small strips of velcro on the camera and cloth such that the cloth doesn't touch the bellows, this is fairly recent however and I will be making some tests in the next few days to verify each of the points made here

jetcode
1-May-2008, 09:05
You can eliminate the lens board issue by rotating the board 180 degrees. If the problem doesn't move to the other side of the frame, it isn't the board.

I'd also try a regular 8x10 back and see if the problem shows up with the different back.

Cheers,

Steve

it's a 4x10 camera but the first suggestion is useful

Mike Castles
1-May-2008, 10:11
It's a negative, therefore, when inverted to match the amount of light hitting the film, it would be darker - less light did indeed hit the film. So you must be looking for something blocking the path of light.



You are correct, of course, should have clicked on the image first. Still, curious why part of the area 'was' exposed. Be interesting to find what this one is.

jetcode
1-May-2008, 10:57
You are correct, of course, should have clicked on the image first. Still, curious why part of the area 'was' exposed. Be interesting to find what this one is.

in truth the underexposed area may be properly underexposed and the rest of the film fogged increasing density

sanking
1-May-2008, 11:18
in truth the underexposed area may be properly underexposed and the rest of the film fogged increasing density

Anything is possible, but the odds IMO are that the far right area is underexposed.

Is there any possibility that you held the dark slide in such a way that it cut off light to the negative for part of the exposure?

Sandy King

Ken Lee
1-May-2008, 12:02
If, as you say, "The lens is massive and barely fits", then perhaps your bellows, or part of the camera itself, is in the way. Hence the shadow on all the images, color or b&w.

Jiri Vasina
1-May-2008, 12:26
You are correct, of course, should have clicked on the image first. Still, curious why part of the area 'was' exposed. Be interesting to find what this one is.

I'm also wondering about that. It would be much simpler if there was no exposure to that part of the image. I'm wondering since I saw that image what could block only part of the light. Or it must be a massive flare/light leak affecting almost 4/5 of the rest of the image (very unlikely, as it would be seen very clearly, and probably would not be so uniform). I'm curious too to hear the reason when one is found...

Scott Kathe
1-May-2008, 12:50
in truth the underexposed area may be properly underexposed and the rest of the film fogged increasing density

As others have said it could be flare but with my limited experience the flare I've observed is never so nice and uniform. If you are using a calibrated meter and a nice evenly lit target you should be able to figure out if you are getting the density you would expect in the majority of the negative or in the small strip.

If you shoot some transparency film you would be able to tell if that small strip is underexposed or the larger part is overexposed as long as your meter is working correctly.

Shoot a sheet of transparency film with a lens that doesn't exhibit this artifact, use the exact same settings on the lens and shutter with the lens that is giving you this problem and that would also tell you what is going on. Heck-you should be able to do that with negative film as well:)

Scott

Christopher Breitenstein
1-May-2008, 13:33
bellows flair? Can you see the increased/decreased density on the Ground glass? Bellows flair is usually visible on the GG, only very slightly though. just a thought.

yours:

Wally
1-May-2008, 13:48
I've processed the same B/W film using a different lens and the effect is not there. The color film was developed elsewhere. I think it is some form of fogging die to light leak at the lens board. This lens is massive and barely fits. The camera is brand new and so far only the 360 has produced these results.

Is this your longest lens? Maybe the bellows has a light leak only when you rack it out that far, and the only place that's not getting hit by the leak is that area, the rest is getting a little more exposure, effectively raising film base. You only see it with that lens, because that's the only time you stretch the bellows that far.

This could happen if a bellows fold has let go on the inside - it's not covering a hole directly, occluding it for that part of the 4x10 frame.

Bill_1856
1-May-2008, 14:01
Sticky, or non-functioning shutter leaf.

jetcode
1-May-2008, 14:08
Sticky, or non-functioning shutter leaf.

hmmmmmm ---- as a matter of fact this shutter is in dire need of a CLA the low speeds don't work at all but it appeared to work on 1/8 and up ---- hmmmmmm