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nray
28-May-2009, 07:52
I just bought my first wide angle lens (Caltar II-N 90mm 4.5 ) for my 4x5 and have been taking some test shots. Is it normal for these wide angle lenses to be soft at the edges? (I checked the negative and it looks soft also.)

Thanks.

Archphoto
28-May-2009, 07:57
At the "standard" photographing aperture of f:22 it should be almost as contrasty as the center, unless you have not the propper distance between the front and back elements.
In that case the lens has to be shimmed for propper spacing.

Peter

Gem Singer
28-May-2009, 08:06
Wide open, some softness at the outer edge of the image circle is normal. However, closed down, the image should be razor sharp from edge-to-edge.

As you know, CaltarII-N's are re-badged Rodenstock Grandagons. They are outstanding wide angle lenses (no charge for the plug, Bob).

Check for fungus. Perhaps it was dropped and an element has been slightly displaced.

Also, is the thin brass shim missing? Un-screw the front lens element and check.

nray
28-May-2009, 08:22
Wide open, some softness at the outer edge of the image circle is normal. However, closed down, the image should be razor sharp from edge-to-edge.

As you know, CaltarII-N's are re-badged Rodenstock Grandagons. They are outstanding wide angle lenses (no charge for the plug, Bob).

Check for fungus. Perhaps it was dropped and an element has been slightly displaced.

Also, is the thin brass shim missing? Un-screw the front lens element and check.


It has been dropped. Can I fix it? It seems to be on one side at the edge, it is soft.

Gem Singer
28-May-2009, 08:31
It doesn't sound like a do it yourself project.

This type of damage requires the attention of a factory trained repair person.

Perhaps Bob Solomon will chime in here and advise you.

nray
28-May-2009, 08:53
It doesn't sound like a do it yourself project.

This type of damage requires the attention of a factory trained repair person.

Perhaps Bob Solomon will chime in here and advise you.

Well, I took a chance when I bought it, knowing it had been dropped.

James E Galvin
28-May-2009, 08:57
If its only soft on one side, it might be that the swing is set wrong. Wide lenses are more sensitive to tilt and swing, as the light hits the film at a large angle. Also the image is dim at the edges, so its more difficult to see that the tilt and swing are correct.

Bob Salomon
28-May-2009, 09:03
It doesn't sound like a do it yourself project.

This type of damage requires the attention of a factory trained repair person.

Perhaps Bob Solomon will chime in here and advise you.

We do not service Caltar lenses. Calumet does. I am sure that they can get this fixed for you.

nray
28-May-2009, 09:14
If its only soft on one side, it might be that the swing is set wrong. Wide lenses are more sensitive to tilt and swing, as the light hits the film at a large angle. Also the image is dim at the edges, so its more difficult to see that the tilt and swing are correct.

Thanks...I'm pretty sure I had it all zeroed out. I am taking some more shots and will keep that in mind. The other thing I noticed is that because of the weight of the lens it tips forward slightly.

Bob Salomon
28-May-2009, 09:58
Thanks...I'm pretty sure I had it all zeroed out. I am taking some more shots and will keep that in mind. The other thing I noticed is that because of the weight of the lens it tips forward slightly.

You can easily determine if the problem is in the lens or the camera. Just rotate the lens and shutter 180 on the lens board and reshoot. If the soft spot moves then the lens has a problem. If it doesn't then the camera has a problem.

Lynn Jones
28-May-2009, 12:02
Here's one other test, nray,

It may need to focus in, focus at 35 feet (or 10 meters) then stop down and see if the entire field is sharp. If it is then always focus at the subject distance until it is farther away than 35 feet (max aperture hyprfocal distance) and then stop down there and carry distance by DOF. This has been common for most 100 degree lenses although the most recent designs have been better.

Lynn

Glenn Thoreson
28-May-2009, 17:48
Wide angle lenses can be harder to focus, also. Be sure to use a dark cloth and loupe. Some older 90mm lenses were ridiculously hard to visually focus. Yours should be much easier.

nray
10-Jun-2009, 18:45
I got some film back using this lens. If any one cares to look, I would appreciate an evaluation of sharpness on this test shot. 120 film @6x12 Roll Film Back.
http://i119.photobucket.com/albums/o131/nray53/scan110A.jpg

It looks soft to me on both ends. The left side more so. Is this normal?
Thanks.

Archphoto
10-Jun-2009, 19:25
No, this is NOT normal.

Were the vertical swings of both standards in their ZERO position ?
And even not, the left side is more unsharp than the right side.

Lens problem.

Peter

Gem Singer
10-Jun-2009, 19:26
"Is this normal?"

No, it isn't.

Your lens is not operating properly.

It needs the attention of a trained repair person.