PDA

View Full Version : classic lens lacks contrast



martinfrank
15-Sep-2004, 07:05
Hi everyone, I've been using a 13"/24"/28" Turner Reich lens on an 8x10 camera, developing HP-5 plus in DDX with BTZS tubes and while the negs are quite sharp, they lack contrast despite increasing the concentration of the DDX developer beyond that recommended by Ilford and increasing the developing time. Any suggestions? Or should I just use a modern, coated lens. Thanks, Marty

David A. Goldfarb
15-Sep-2004, 07:22
Are you using an adequate lens shade? An adjustable bellows-type shade will improve contrast not only by shading the lens from flare outside the camera, but also by restricting the image circle inside the camera to reduce bellows flare.

Steve Hamley
15-Sep-2004, 07:25
Martin,

Try a good lens shade, and shine a bright light through the lens and observe if there's any haze or fog, especially with the light off-axis or just outside the field of view. Many folks believe this haze cuts contrast more than you would think, and most old lenses have quite a bit if the glass hasn't been recently cleaned.

If none of the above helps enough, I'd say try the modern multicoated glass.

Steve

John Cook
15-Sep-2004, 08:04
Marty, I agree with the others that it sounds like internal camera flare - light bouncing off the bellows onto the film.

If you donít have an expensive, super-dooper lens shade to test the theory, here is a trick taught to me by an old-timer in Hollywood, 50 years ago. He had a 4x8-foot piece of plywood (you can use a piece of foamcore) painted flat black, on legs with casters, with an 8x10 hole cut out of the middle to shoot through. He would move it in and out, in front of his camera until the edges of the hole were just out of his frame. It totally blocked off all light which did not directly land on his film. And it worked with any focal-length lens. Should dramatically improve contrast.

Jerry Flynn
15-Sep-2004, 10:16
Steve's comment about haze reminded me that I had a coated lens that developed a haziness after about 25 years. It was not fungus, just an overall haviness that was more noticable near the edges. The result was a loss of contrast due to overall flare.

A trip to SJ Grimes for re-cementing remedied the problem. If memory serves, it cost around $150 or so.

CP Goerz
15-Sep-2004, 10:22
Also try a lower speed film as they are a bit contrastier. A #8 filter also helps too, if you are using the lens in a single celled form then a stronger #15 or 22 really helps out. I found that the single celled use does lower contrast by a grade roughly.

CP Goerz

Brian Ellis
15-Sep-2004, 11:26
Increasing developer concentration won't by itself have any effect on contrast. Increasing development time should because increasing the time has a disproportionately greater effect on the highlights than it does on the shadows. The shadows are virtually fully developed roughly half way through the development time, the density of the highlights continues to increase as the development time increases up to the point where the film can get no denser. How much did you increase the development time? Something around 30%-50% more should increase the density of the highlights by a stop or so.

Older lenses like the Turner Reich tend to produce less contrast than modern lenses but increasing the development time should work, especially when combined with things others have suggested.

Jay DeFehr
16-Sep-2004, 09:04
"Increasing developer concentration won't by itself have any effect on contrast"

I don't understand that statement. A more concentrated developer will be a more active developer, which is why more dilution requires more time to build the same density. If one were to change nothing but the concentration of the developer, I assure you the contrast of the negative would be affected.

David A. Goldfarb
16-Sep-2004, 10:30
I think it's going to depend on the developer.

Recently, for instance, I've been experimenting with XR-1 as a high-speed developer, and found that increasing the concentration also gave me an increase in base fog, so I didn't really get more contrast that way, but doubling the borax at the 1+1 dilution gave me some more contrast without as much increase in base fog.

Jay DeFehr
16-Sep-2004, 11:37
I'd be willing to bet that a circumstance in which the increase in base fog due to increased developer concentration perfectly matches the increase in highlight density, resulting in no change in contrast, is a rare one. I think that it's safe to say that for all practical purposes, developer concentration affects contrast.

Brian Ellis
20-Sep-2004, 04:57
"If one were to change nothing but the concentration of the developer I assure you the contrast of the negative would be changed."

"I think it's safe to say that for all practical purposes developer concentration affects contrast."

Yes, if nothing else is changed (i.e. if you developed the more concentrated developer for the same time as the weaker concentration). However, when manufacturers contemplate that developers may be used at different concentrations (e.g. Rodinal, HC110, D76) they also provide different times for each concentration. For example, the label on the Rodinal bottle provides for different concentrations and different times depending on the concentration that is used. If the instructions are followed when the concentration is increased then the development time is reduced. When that's done there is no change in contrast between the longer time with the weaker concentration and the shorter time with the stronger concentration. That's what I meant when I said that changing the concentration doesn't affect the contrast.

I agree that if Rodinal, for example, was for some reason used at the 1-10 concentration and developed for the 1-50 time, or if D76 was used undiluted but developed for the 1-1 time, the contrast would be different than if the recommended times for the stronger concentrations were used. However, when that's done it isn't the change in concentration by itself that increases the contrast, it's the combination of changing the concentration and using a longer than normal development time for that concentration. That's what I meant when I said that changing concentration by itself doesn't change contrast.