lens mystery...

[Percy]

Hi.

I am having trouble with a lens/4x5 combo. Actually, it's a Cambo (no pun intended). I am unable to focus a 127mm Kodak Ektar on this camera. I have called Calumet; I was informed that I should perhaps "rethink" large format photography since I am unable to do this. Another person, from a retailer in NY, told me it HAS to focus, given that a 90mm will focus on a Cambo.
I have tried everything, including moving the rail clamp in front of the standard clamps.

The lens works fine on my Speed Graphic. I am particularly fond of this piece of glass, and would like to use it on my monorail. Any suggestions...(I guess a recessed board is in my future).

[Nick_3536]

Is it on the same board? Or did you remount it? I'm guessing you remounted it. Maybe it's not screwed tight. Maybe there is a different issue with the new or old board.

[Ted Harris]

Percy, you need to give us some more info. The problem may be that you do not have a long enoough rail to acheive the need extension. This couldbe the case ifi you are trying to focus on an object that is placed close to the lens. Remember that the bellows extension needed for a lens increases as the object you want to bring in focus gets closer to the lens/film plane. At one-to-one for example, you need twice the bellows extension you need at infinity. Having said that, 250+ of rail is still rather short. You mentioned a recessed board and this leads me to believe you are going in the wrong direction to acheive focus ... you may need more extension, not less. If you are trying to focus at infinity then the above doesn't apply ... all a guess without more detail on exactly what you are doing that isn't working.

[Ben Calwell]

Percy,
If you're using a loupe to focus on the ground glass, check to make sure the loupe is adjusted to your eyesight. It happened to me once. A few years ago, I thought I couldn't focus a lens on my newly acquired Linhof, but it turned out that my adjustable loupe had become "unadjusted" to my eyesight. It was embarassing, because I sent Jim at Midwest (where I bought the camera) a frantic e-mail claiming I couldn't focus the camera. But it just turned out that my loupe was out of adjustment for me. After I focused the loupe to my eyesight, everything popped into focus on the ground glass.

[Percy]

I know how to focus...it is not an issue of inadequate bellows extension. The lens is mounted on the graphic (4x4) board, which is in turn mounted on a Cambo 4x4 adapter board. There is no issue with my loupe; I have 20-10 vision...better than average.

[neil poulsen]

"I was informed that I should perhaps "rethink" large format photography since I am unable to do this. "

This is terrible. Obviously, that Calumet person hasn't had a lot to do with large format. Probably never shot a roll of film.

Have you used this lens before?

[Ron Marshall]

Percy, is the problem that you cannot get the lens close enough to the ground glass to form an image?

[Conrad Hoffman]

No rocket science here- hold lens and board in left hand with shutter open. Focus a distant object on a piece of paper held in right hand. Note distance between lens and paper. It should be about 127mm! Figure out why you can't achieve that distance in the Cambo- maybe the adapter is too thick. Get recessed board if necessary. Does one camera have a fresnel screen, and the other not? They'll be brighter, but harder to focus with. A few minutes doing some rough checks with a ruler should sort this out.

[Sam Crater]

Conrad has the right idea. Focus the lens on a piece of paper. If you can't focus on the paper, the lens is mis-assembled. If you can, measure the distance to the paper and figure out why you cant achieve the same focus at the same distance with your camera.

[William Mortensen]

Very confusing situation, given that the lens focuses fine on your press camera. The camera really doesn't do anything but hold the lens on one end and the ground glass on the other, and keep out the light inbetween. One possible guess- could there be a fresnel screen installed on the wrong side of the ground glass? What kind of image do you get with the bellows set to about 127mm?