Overexposed negatives when tilting lens

[jasonjoo]

So I just got out of the darkroom (my second time developing 4x5 negs!) and noticed that on the photos that I used tilt movements, the negatives came out very overexposed (can barely make out the outline of someone's face). The first time this happened, I thought I had a bad batch of film (was using the film that was in the holders that I purchased... the previous owner said it was FP4 and wasn't in the fridge for an unknown duration of time).

The photos were taken indoors on Arista.EDU Ultra 100 4x5 sheet film. I was using my brand new Chamonix and new-to-me 150mm Sironar-S. Exposure taken from an incident meter was: 1/30th, f5.6, ISO 100. Bellows draw was roughly 7" to 8" and I did compensate a little bit for this. I developed the negatives in HC-110 diluted to 1:50 for 7 minutes @ 68º F.

5 out of 6 negatives turned out perfectly fine. It's the last one where I tried tilting the lens upwards to gain shallow DOF that came out very overexposed.

Any ideas? One possibility is that I hand tightened the retainer screw when putting the lens on the lens board. My lens wrench has not arrived yet and I was eager to put some film through my first LF camera.

Thanks in advance!

Jason

(Won't be able to scan samples in until tomorrow night... But I didn't even bother hanging the blown out negative to dry...).

[poco]

I'd take a close look at where the bellows attaches to the front standard. You may have a slight separation that only opens up with the stress of a tilt.

[gari beet]

depends how much tilt you used and also wether you used alot or rise or fall maybe, the combination of moving the image circle with rise/drop and front tilt could have caused some fall off of light.
I have had this problem if I have used alot of front tilt when shooting landscapes, say if I am shooting wide and close to the ground and trying to carry DOF from front to back. A few times I have had to use grads on the bottom to account for the difference in light falling on the base of the chrome. Largish bellows factor and a good amount of tilt has sometimes amounted to 2 stops..
Maybe not as you weren't using a huge amount of draw but worth having a look even just to discount the possibility at least, I would say.

Cheers

Gari

[Kevin Crisp]

Since you are new to this is there a possibility that on the last one you relaxed a bit and forgot to stop down? An easy mistake to make over and over again, from personal experience. If you can see enough of the negative you might check to see if the depth of field was what you were expecting. Maybe a leak that only opens up when tilting? Try testing the camera to see if it is light tight when stretched in a similar manner. Are you absolutely sure the film holder is in all the way on the left, they can very easily false seat causing light leaks. They can look and feel like that seated normally when they didn't.

[Brian Ellis]

Tilting a lens by itself normally wouldn't cause overexposure. Tilting the lens changes the plane of focus, which normally doesn't have any effect on exposure especially with an axis tilt camera such as your Chamonix. Since your camera is brand new a problem with the bellows or anything else related to the camera seems unlikely and the lens/lens board apparently is fine since your "non-tilt" negatives turned out fine. That leaves the holder as a possible source of an equipment problem but light leaks from holders don't normally show up as complete overexposures, usually they show up as streaks or as partially overexposed areas, whereas from your description here it sounds like the entire negative is grossly overexposed.

Kevin's thought that you opened up to compose and then forgot to stop down to the taking aperture would be a good one except that you say your exposure was at f5.6, which is as open as the shutter on a Symmar-S gets (i.e. your composing/focusing aperture and your taking apertures were the same and I assume the exposure at f5.6 was intentional). His thought that the holder wasn't seated properly seems more likely to me. Or since you're new at this, maybe you didn't meter the scene correctly (assuming there was some change in the lighting of the tilt photographs as compared with the ones that turned out fine). In other words, my guess is that the problem is something you did, not a problem with your equipment.

Obviously you need to make several test photographs, some without tilt and some with, making sure that the ONLY difference is the tilt. Be sure to keep track of which holders were used for each negative. If you still get overexposed negatives with the tilt and only with the tilt, and making sure that tilt is the only difference, then you have an equipment problem with either the camera or the holder, unlikely as that seems based on what you've said here.

[jasonjoo]

Thanks guys, I appreciate your help.

I'm unsure if I have to meter in a different way when tilting the lens, but for the most part, the location I was shooting was getting a pretty consistent amount of light. I took a reading with my incident meter before each shot and got the same exposure each time.

Most of these issues are probably user error. I'll have to do a bit more "scientific" testing to make sure. But so far, the consensus is that whenever I tilt the lens, my negatives are very overexposed. I'll do a few more tests this week and see how things go.

Jason

[D. Bryant]

Thanks guys, I appreciate your help.

I'm unsure if I have to meter in a different way when tilting the lens, but for the most part, the location I was shooting was getting a pretty consistent amount of light. I took a reading with my incident meter before each shot and got the same exposure each time.

Most of these issues are probably user error. I'll have to do a bit more "scientific" testing to make sure. But so far, the consensus is that whenever I tilt the lens, my negatives are very overexposed. I'll do a few more tests this week and see how things go.

Jason

Jason,

Titlting the front standard doesn't cause more light to strike the film, so tilt by itself does not cause your over exposure. You have another problem that is causing the over exposure.

Don Bryant

[Fred Leif]

Curious.

You mentioned that this was your second time developing 4x5 sheet film. Is this still early in your development of large format work habits?

One sheet out of 6 with major overexposure problem suggests a one time inconsistency of your method.

It is possible that this overexposure could result from pulling the dark slide without having restored the shutter to the cocked position after focusing on the ground glass ... essentially overwhelming the exposure. I know I've done this a time or two.

With static subjects, and a well locked down camera it might be hard to tell whether the exposure is only due to the shutter ... versus having left the lens open in the focusing position when the dark slide is drawn.

[jnantz]

It is possible that this overexposure could result from pulling the dark slide without having restored the shutter to the cocked position after focusing on the ground glass ... essentially overwhelming the exposure. I know I've done this a time or two.

i still do that from time to time, and i've been at this for a while ...
it is easy to forget something like stopping down.

have fun!

john

[jasonjoo]

Curious.

You mentioned that this was your second time developing 4x5 sheet film. Is this still early in your development of large format work habits?

One sheet out of 6 with major overexposure problem suggests a one time inconsistency of your method.

It is possible that this overexposure could result from pulling the dark slide without having restored the shutter to the cocked position after focusing on the ground glass ... essentially overwhelming the exposure. I know I've done this a time or two.

With static subjects, and a well locked down camera it might be hard to tell whether the exposure is only due to the shutter ... versus having left the lens open in the focusing position when the dark slide is drawn.

Hey Fred,

Yes I have done this twice (yikes!) already. I've only tried to expose maybe 10-12 sheets so far too, so my fail rate is quite high . However, I know that I didn't accidently pull the dark slide while the lens was open because the shutter won't let me "trigger" it when the aperture is placed in the open position. The two times that I did make this mistake, I discarded the films completely and started with a fresh sheet of film.

Since everything is a bit muddy right now, I'm going to take a few photos with the lens tilted and without and develop the film and see whats up. I'll also check the bellows for any small holes but I don't think this is the issue.

Another thing is that I hand tightened the retainer screw to mount the lens onto the lensboard. This may be the problem as well, so I'll hold off on testing until my lens wrench comes so I can tightly mount the lens to the board.

Thanks guys, I really appreciate your help!

Jason