Newcomer needs help. Possible Lens problem??

[kingfisher]

Hi, I got my first sheets of 4x5 negative film back from the lab this week. I've only had a chance to scan a couple but they all seem to be losing focus on the right hand side of the image. The left side is sharp but the image gets increasingly soft from the centre to the right edge of the frame and also at the extreme edge on the left. This seems to be the case when viewing the unscanned images through a loupe also. I've discussed this with the technician at my gallery who suggested It may be a lens problem although he's not familiar with view cameras. I've uploaded an example with details from each side of the image cropped at 100%.

The green square shows the sharp area. The red shows the image getting softer on the right out to the edge of the frame.

This picture was shot using a Sinar 4x5 camera just before dark.

Lens: Schneider - Kreuznach Super Angulon 90mm f8. The lens looks clean and free from dust, smudges etc.

f16

1 min exposure.

Fuji Pro NS 160 negative film.

Other than focusing, no camera movements were used. All planes were level.

As this is my first time using a view camera, perhaps I'm doing something wrong.

Any advice would be very welcome before I purchase a new lens.

Image

Sharp Area (left)

Soft Area (right)

[Two23]

If the standards weren't parallel, that would do that.


Kent in SD

[E. von Hoegh]

If the film was not loaded properly it could do this.

[johnielvis]

if it's ALWAYS not sharp in the left side..not matter how much you move the lens in and out, then it's the lens...

if it gets sharp by racking the back in and out, then something isn't alligned right---since you see the dullness on the ground glass, you should also see if it is able to be sharpened up by moving the back back and forth.

if not...the lens is......something wrong....cross-threaded? I've never seen a lens be halfway sharp ever like that--it's usuall all over and uniform all around.

[Kevin Crisp]

I'd guess some inadvertent swing front or back. If you focus on something uniformly distant and check the ground glass with a loupe is it sharp on both sides?

[kingfisher]

I've re-checked the front and back standards to ensure they're parrallel. They seem accurate now, and after focusing front and back, everything looks sharp on the ground glass across the whole image. It seems a slight swing at the back may have been the problem. I'll run a few test shots to make sure. Thanks for all the help.

[Bob Salomon]

Turn the lensboard so the lens is upside down and shoot another test. If the same side is still out the problem is the camera. If the problem rotates with the lens then the problem is the lens.

[cyrus]

YOu may be moving the back when you insert the filmholder?

[Peter Gomena]

Your lens may not be mounted properly in the lensboard. The retaining nut or ring probably has a shoulder on it that fits snugly into the hole in the lensboard. If the ring is not squarely in the hole, your lens will be cocked at an angle.

Peter Gomena

[captivelight]

Could you have loaded the film wrong and allowed the film to bind on the right side causing it to bow out of the focal plane?