Sharp focus. Blunt results

[Mahombi]

Has anybody had problems with unsharp negs, using Horseman 6x12 backs on an Ebony SW45? I have been very careful to focus accurately with a loupe, made sure the camera was perfectly still before exposing and set the aperture to f22. Yet the negs are slightly soft throughout. Surely this can't be diffraction, can it?

[darr]

Was your film taut between the rollers? Just a suggestion. I have never used the 6x12 back, but I do use 6x9 and 6x7 backs with a SV45U with good results.

[Paul-Owen]

I've used the very same set up with no problems whatsoever. All I can think of is that the film may not be wound tightly onto the take-up spool. When loading film I tend to introduce some resistance to the film leaving the film spool so that the backing paper/film loading onto the take-up spool is taught. Might be worth a try??

[Brian Ellis]

It almost certainly isn't diffraction at that aperture, especially if you can see the softness just by looking at the negative (as opposed to seeing it in a big print). Most likely it's a holder problem as darr and Paul suggest.

[robc]

Has anybody had problems with unsharp negs, using Horseman 6x12 backs on an Ebony SW45? I have been very careful to focus accurately with a loupe, made sure the camera was perfectly still before exposing and set the aperture to f22. Yet the negs are slightly soft throughout. Surely this can't be diffraction, can it?

Your assertion that the negative is soft throughout is highly improbable. If the film plane were out of position then something either in the foreground or background is likely in sharp focus. Assuming you remember exactly where the plane of sharp focus was supposed to be, you should recheck the neg and see if either foreground or background is actually in focus. That will tell you if it is a focussing and/or film plane error.
You have not told us what lens you were using. Wide angle lenses require very accurate focussing and there is no room for error so correct alignment of everything is critical.

If everything really was as it should be then it could be a lens problem. Or does your Ebony have its fresnel fitted cos if it hasn't that could also be the problem.

Does the same lens using a normal film holder give the same problem on the same camera.

[Mahombi]

Well folks, I've checked for film flatness (and slackness!). All seems to be well on that front. Certainly as flat as on my Hasselblad back. I've just tried to deliberately load a roll of film loosely and found that the holder would have none of it. It pulled it as flat a normal. I feel the same as robc about the softness throughout issue. I was beginning to think it was my eyes. But when I compared the negs with an old 35mm neg shot on APX25, the APX was clearly much sharper. I'm using ACROS 100, so I guess it may not be as sharp as Fuji boast. Then again, it probably isn't a fair comparison.

I've shot a test roll on some flat copy (a newspaper). Stopped down to f22. Whilst the detail is sharp, in as much as the small print is perfectly legible. That crispness of sharpness just isn't there.

This problem happens with all three of my lenses; 80mm & 110mm Super Symmar XL's and 180mm Apo-Symmar.

[Ben Crane]

The problem may be that your ground glass is not aligned properly. Thus the image may be in focus on the ground glass but not on the film plane because the film plane is in a different place. This can be investigated by getting items with fine print such as a book or dollar bills. Get five or so items and place some closer and others further away from the camera. Focus on the middle item and make a negative with the aperature wide open. After you develop the film you should see the the middle item (the one you focused on) is in the best focus. If one of the other items is in focus your ground glass is misaligned and needs to be adjusted accordingly.

[robc]

That crispness of sharpness just isn't there.


which developer are you using?