Gg image in focus but resulting negative out-of-focus

[tonyowen]

Attachment 135902Attachment 135901

I’ve a Calumet CC401 4x5 cameras fitted with a Schneider Xenar f4.7 135mm.

I’m new to 4x5 work so I ’m just playing around getting use to the camera and lens.

Twice I’ve taken a picture (portrait is too formal) and on both times the resulting negative has the subject out-of-focus though the background is in focus.

However, in both cases the GG screen image was in focus (with and without using a 8x Agfa Lupe).

The camera to subject distance was around 1.5 to 2.0m.

The camera settings were 1/60s @ f7 (outside image) and 1/4s @ f8 (inside image).

I pretty certain the camera was not knocked or moved and I’m certain that the camera was not moved on its monorail.

Attached are scanned images of the (inverted) negatives.

Any observations and help welcome

Regards

Tony

[Ari]

Tony, what's happening is that your film holders are causing your film to be on a different plane than that of your ground glass.
Check them to see if there are any obvious problems, or if perhaps you loaded your film incorrectly. Maybe you seated the film holder improperly.
If they are old, worn out film holders, find or borrow a known good one from a friend or store, and make a comparison.

[jp]

Sometimes the groundglass+fresnel sandwich is reversed, causing it to focus on the wrong plane. Some cameras there are also clips for holding the GG and maybe the GG is installed in the wrong place? (previous owner repair issues)

[Old-N-Feeble]

Or someone may have replaced the GG/Fresnel... or removed a Fresnel... or added one. Any one of these will move the focus plane wrongly.

[Tim Meisburger]

Tony, take the back off, lay a straight edge across it, then measure down to the ground glass and record. Then insert a film holder with a scrap negative inside and repeat. The measurement to the negative should be exactly the same. If it is not, that is your problem. If it is, then check to make sure that the ground face of the glass is facing into the camera. If it is, then I am stumped. The face of the ground glass and the film should be on exactly the same plane.

[Jim C.]

First thought that comes to mind is the ground glass reversed ?
I had the same issue with a Century Grand, the gg image was sharp but the neg was out of focus.
The matte side of the gg should be facing inside the camera.

[Tim Meisburger]

No responses when I started writing and three before I finished!

[N Dhananjay]

Two possible reasons that occur to me.
1) Subject movement - have you tried making a photograph of something static to rule this out? I would suggest photographing a scale or ruler. Focus on, say, the 6" mark and see whether it is the 6" mark which is in focus on the neg.
2) Mis-registration of GG and film surface: When you put in the film holder, the film should be where the GG was, otherwise, there will obviously be focus errors. Especially if an after-market fresnel was installed the wrong way, it can mess up this registration. Some cameras were designed to have a fresnel on the inside of the GG and the registration was compensated accordingly, Most have a fresenel on the outside in which case, you could use a depth micrometer to check for whether the GG plane is the same as the film plane. I would start by ruling out 1 above and then proceed to 2.
There could be other more esoteric sources of focus error but I'd start here.
Good luck tracking down this gremlin.
Cheers, DJ

[AJ Edmondson]

The CC401 did not come from the factory with a Fresnel... should have been a gridded ground-glass (red lines). The matte side should face the lens and, if the GG has been replaced the orientation should remain the same. If the glass is reversed the plane of focus for the film plane will be displaced by a distance equal to the thickness of the glass. It will appear to be in focus to your eye but the film is registering forward of the plane.
Joel

[tonyowen]

The CC401 did not come from the factory with a Fresnel... should have been a gridded ground-glass (red lines).l

Thanks to all of the replies.
The ground glass has red lines - but whether it is the right way around I do not (yet) know
I'll follow all of your suggestions - I agree with the logic of all replies - now I have to test them one by one.
ps a correction to my initial posting the subject camera distance was 1m - which should no tmake any difference.
regards
Tony