Problem with RF Alignment, Film Flatness....or what?

[JHenry]

So, I have a problem and hope the great members here can help me out. Sorry about the length of the post, but I'm about to leave for a trip and wanted to include detail in the hopes somebody can help me.

I recently got some processed film back from the lab and ran it through my scanner (Nikon Coolscan 5000). Many of the scans came out with very soft focus. At first I thought this might be a scanner issue, since I haven't used the scanner in a few months. I then scanned a few more rolls, checking out to see if the problem was related to B&W versus E-6, or correlated to camera bodies.

Unfortunately, it appears the problem is associated with my Zeiss Ikon. All the film that came from the ZI is soft, whereas the film that went through my R4A is nice and sharp. Also, film from about 2 months ago that went through the ZI was nice and sharp. Based on all this, I'm pretty confident it is not the scanner.

Now, I can tell that the rangefinder is just slightly out of alignment. At infinity things in the distance don't line up perfectly in the rangefinder patch. However, I'm not convinced it is only a RF alignment issue.

The pictures that are out of focus were mainly taken outside on bright sunny days, and they are primarily of landscape. I mention this because I would have focused near infinity (due to landscape) and I would have used anywhere from f11 to f22. While I didn't keep a record, my guess is these taken with a shutter speed of between 1/250 and 1/1000, hand held, and all with a 35mm ZM C-Biogon.

I mention the above, because with the given f/stop and shutter speed, even if the rangefinder was/is out of alignment, wouldn't the shots still be in focus given depth of field?

Is it possible that the film is not lying flat? I'm at a loss for other explanations at this point.

I'd appreciate any insights or thoughts anybody has. I'm leaving in 6 days for a trip to Morocco (2 weeks) and Scotland (1 week). I was going to bring my M7 (just back from servicing at Leica NJ), my ZI and R4A. But, at this point I'm a bit scared about putting film through the ZI. I'd hate to get back and find out that all the film put through it is not up to standard.

Thanks for your help.

Jeff

 

[antiquark]

Random questions:

- is the pressure plate still springy?

- if you load film, then open the shutter in B mode, does the film look like it's laying flat? Or is it bulging or warped?

- if you set the lens scale to, say, 2 m, does the rangefinder patch focus properly at 2m?

- at F22, diffraction might cause softness. Would that be the problem? (usually lenses are at their sharpest at around f5.6 - f8. )

- Was there any point in the image that was sharp? I.e., if there was a field of grass in the scene, was there a sharp area closer to the camera?

- If you feel really motivated, you could tape some scotch tape (the frosted kind) where the film would be, then use a loupe to manually confirm the focus. Just don't let the tape touch the shutter, or you'll be crying. 🙂

 

[antiquark]

Also, just to avoid any confusion, can you post a sample of a sharp picture and a soft picture?

 

[ferider]

You can only find out what's wrong via testing. Start with something simple: a known good lens, best a wide angle (shorter DoFocus), at infinity, on a tripod with cable release, at f5.6 or f8. Ignore the RF alltogether, just check for infinity collimation.

This will tell you if flange and flange/film distance and pressure plate are OK, and that you are loading the film correctly.

Next, see if one or several lenses caused your problem. Same experiment as above but with other lenses.

Last test the RF, by doing controlled 1m, 3m, and close to infinity shots. Best with a longer, fast lens (Shorter DoField), with long throw. Still on tripod and compare lens focus scale & RF alignment with an actual distance measurement.

Best is to check the negatives with loupe on a light table, rather than via scanning, so you can exclude scanning problems.

Good luck,

Roland.