Question About Focusing Problem!

[rshorosky]

hello everyone,

i recently began shooting 4x5 after moving up from medium format and have been having difficulties getting fully focused negatives. initially i thought it may be the camera (toyo 45cf) but after a shooting with a different field camera i had the same results. when i scan the negatives the focus looks a bit soft for what 4x5 should look like and i am unsure as to the reason for this. as to my work flow i have ruled out most things as i am very meticulous when i shoot so if anyone has any ideas or suggestions to resolve the problem that would be great.

when shooting i always use a loupe to focus off of the ground glass and i mostly shoot at f32-64 so depth of field cannot be the problem. i also have used different film holders so i do not think it is a problem with the film holders either. so far my only theories as to the problem are possibly it being my eyes as i wear contacts, but have had someone double check my focus and that didn't really seem to be off), or the possibility of it being the way i am loading the film/ the film's plane in relation to the camera's plane?

if any would like i can upload a scan of one of the negatives for further help.
thanks again and any and all suggestions, comments, advice would be greatly appreciated!

sincerely,
ryan

[Robert Hughes]

It's possible your ground glass is not seated properly at the film focus point - or the film holder itself is not seated properly.

One way to test your camera's focus would be to photograph a ruler, laying on a table so that the scale runs away from the camera. Focus to a particular scale marking on your ground glass, expose and process, then view the negative with a loupe to see where the actual focus point is.

[rshorosky]

robert,

thank you for your reply. as to the possibility of it being the film holder, is there any way to tell if the holder is not seated properly without going through the process of photographing and checking the negative? i have never had a problem loading the actual holder onto the camera but is there a way to tell if when the holder is seated on the camera back that it is properly positioned?

[E. von Hoegh]

A scan would surely help. If you are comparing MF negs shot at f8 to LF negs shot at f64, the LF negs won't look too good. Diffraction at f64 will make them less sharp.

Is your loupe focussed on the GG? Do this with the lens removed, you should be able to see the texture clearly.

[E. von Hoegh]

robert,

thank you for your reply. as to the possibility of it being the film holder, is there any way to tell if the holder is not seated properly without going through the process of photographing and checking the negative? i have never had a problem loading the actual holder onto the camera but is there a way to tell if when the holder is seated on the camera back that it is properly positioned?

The ridge on the holder will seat in the groove on the camera back. You are loading the film under the little lips on each side, right?

[Robert Hughes]

You are loading the film under the little lips on each side, right?

I believe they are called "tangs". My kids love Tang! One of them breathlessly told me the other day, "You know, Astronauts drink Tang!"

[E. von Hoegh]

I believe they are called "tangs". My kids love Tang! One of them breathlessly told me the other day, "You know, Astronauts drink Tang!"

No, no, "tang" is the part of a knife blade that the handle is mounted on.
Tang commercial, 1970s

http://www.youtube.com/watch?v=Wf1kw5Yp9Ck

[rshorosky]

as far as the problem being within loading the film and loading the holder onto the camera i have had very little difficulty doing both and am sure i am loading the film properly as well as the holder onto the camera back.

as far as focusing while shooting, yes i focus the loupe directly onto the ground glass and have no difficulty doing so, so i don't think that would be the problem.

with refraction, would that throw the focus off of the entire image dramatically at f45/64 because when i look at my negatives even the objects/areas where i physically focused on through the gg are a bit out of focus.

[E. von Hoegh]

Diffraction, not "refraction" would soften the entire image slightly. Without seeing a scan, we're just guessing here.

[Gem Singer]

Ryan,

It's very possible that the ground glass on your camera is not in the same film plane as your film holders. Possibly a manufacturing defect.

In that case, it might need to be properly shimmed by a skilled camera tech.

There are methods to test for that problem, but it is not a simple matter to correct it.

If you're certain that the problem is not caused by your eyesight, the film holders, or diffraction, have the camera checked by an expert.