Focus Ansco film holders versus Fidelity Elite/Deluxe...?

[Torsten]

Hi,

I'm pretty much a beginner in LF-Photography. I recently got an Agfa-Ansco 8x10 with 3 filmholders (Ansco). A friend of mine borrowed me 2 Fidelity film holders charged with TriX. All my first images on TriX with these newer style film holders lacked totally of sharpness. I mesured the difference in depth: the original Ansco Film holders are 0.6mm deeper than the fidelity. I used a 480mm Apo-Ronar with a packard shutter, 8s at f/22.
How do you explain that I manage now using Ansco film holders to get a good sharpness, how is it possible that 0.6mm make your image unsharp...?

thanks and sorry for these stupid questions
cheers

Torsten

[Ash]

The image on the ground glass is focused using distance - the length between the lens and the focal plane is critical.

If you have a film holder .6mm deeper, that is like focusing .6mm further, so whatever you are focusing on will no longer be totally sharp.

[Kevin Crisp]

How are you making the measurement? Are you saying one film holder type produces better results than the other or just that the newer ones were not sharp? A lens that long with an exposure that long could easily cause an unsharp image that might result from movement of the camera during the exposure, if the camera is not mounted very securely. Don't be afraid to stop that lens down to F:32 or f:45 unless you are deliberately trying to have some parts of the image out of focus. Is the whole image unsharp? Or did you miss the point you were trying to focus on and end up with sharp focus of something in front of or behind what you wanted?

I personally used both the ansco and fidelity ones and never had a problem with either, using the same camera you have.

[Louie Powell]

Thorsten -

With a view camera, one focuses on the ground glass. Therefore, a critical requirement is that the ground glass be in the same position relative to the lens that the film surface will be when the filmholder is inserted into the camera.

To achieve that requirement, there is an industry standard specification that defines the dimension between the outside of the film holder and the surface of the film. For 8x10 holders, this dimension is 0.26 =/- 0.016 inches (6.606 +/- 0.4064mm).

As I understand your description of your problem, you are able to produce sharp negatives using the Ansco holders in your camera, but not with the Fidelity holders. And you have measured the holders and found that the Ansco holders are 0.6 mm deeper than the Fidelity holders. This difference is greater than the tolerance in depth allowed in the filmholder standard.

Fidelity holders are relatively modern - they were still being manufactured a couple of years ago. The Ansco holders are obviously much older.

You didn't indicate how severely out of focus the images made with the Fidelity holders are, and I'm not smart enough to predict how severely a 30% difference in the depth measurement would defocus an image. Perhaps someone else could do that.

But it certainly appears to me that the problem is that your Ansco camera and holders are consistent with each other, but they do not conform to the industry standard for filmholders.

There are two possible explanations for this difference. One is simply that your camera and holders are very old, and predate the development of industry standards. Another is that your camera and holders were originally intended for glass plates rather than film, and the 0.6mm difference in depth was the expected thickness of glass plates.

There are several possible solutions. One would be to modify the camera. While not impossible, that could require careful carpentry. Another solution would be to modify your Fidelity holders to provide additional depth. This could be done by gluing some kind of shim material to each face of the holders to increase the outside to film plane dimension by about 0.6 mm Finally, you could contact a specialty film holder maker (Sandy King of S&S comes to mind) about having some holders made that are dimensioned to match your camera. You should expect that solution to be expensive.

[Gene McCluney]

I have used Agfa/Ansco film holders in 8x10 interchangeably with Fidelity, Lisco and Kodak holders for years and have never noticed a difference, on my Agfa/Ansco 8x10 camera. I would examine every part of your chain in taking the photo. Did you get a tack-sharp image on the ground glass prior to exposing a sheet? 8 seconds is a long exposure, was there any wind blowing?, which can really affect sharpness on a large camera outside. F22 is not very stopped down for 480mm ApoRonar. Lots of things can affect sharpness.

[Gene McCluney]

On an old wood camera, with wear, even the act of inserting the film holder can cause the back to shift enough to put the plane of sharpness out of the film plane.

[Brian Ellis]

Without seeing the photographs and knowing the conditions under which they were made it's hard to do anything other than speculate. But FWIW, I don't think .6 of a mm should make that much difference in the appearance of "sharpness" unless you're making gigantic enlargements. Any time you make a photograph, with any lens using any camera, there's only a single narrow plane of the image that's truly "in focus," i.e. that's represented by a point rather than a circle on the negative (slight oversimplification but basically accurate). Everything in front of and behind that in-focus slice of the image is technically out of focus but appears to be in focus because the resulting circle is sufficiently small that it looks like a point to our eyes (depending of course on all the variables relating to depth of field).

If .6 of a mm (about 1/50th of an inch) in depth of a holder caused everything to appear out of focus then none of us would ever make "sharp" photographs. Also, film holders aren't precision instruments. I own old wooden holders, old plastic holders, and new plastic holders. I can make sharp photographs with all of them but if I cared enough to measure I'd be very surprised to find that all of them are within the ANSI standard.

Unless you do a serious test of the two holders, which would involve making a series of identical photographs, one group with the Ansco holders and one with the Fidelity, leaving everything exactly the same except the different holders, it's going to be hard to know that it's the .6 of a mm that's causing the problem. I'd guess that something else was going on that caused the difference in sharpness among the two groups of photographs.

[Gene McCluney]

I have a turn-of-the century ultra-wide-angle lens for 8x10 that for the life of me, I cannot get a sharp negative from, regardless of what the image looks like on the ground glass.

[rwyoung]

Gene -

It is very possible that the lens you are having problems with focuses the different colors of light at different distances. This can cause no end of problems.

[Randy H]

MAN! I appreciate this thread. Really, really!
I had experienced the same issue, sorta. I noticed that shooting sort DOF shots, that some were coming out good, and others were "kinda fuzzy". I figured it was just grand-dad's poor eyes, or camera movement, or shakey fingers loading the holder, etc.
My holders are all F-G woodies. Have cleaned them, kept them taped good, etc,etc. Never even thought about difference in depths on them. At one time, I thought problem might be in FP/Lens spacing, but still, some shots were coming out decent, some not so good. Last evening, I got them all out, and started checking, and out of about 15 or so holders, there is indeed nearly 1/16 inch difference from the "thinnest" to the "thickest" holder. All same type holder! No need to mic them! If film plane is near center, and holders are overall different thickness... Damn!! Talk about feeling stupit! I would have never even thunked that one.
Thanks a lot, horsten! Guess now I gotta figure out which ones work and which ones need to be either chunked or fixed. Damn!