Centering on lens boards

[garpet]

I bit the bullet and got a large format camera (4x5). The lens board they had for the camera was copal 0, and the lens I had for it is copal 1. I thought this was nothing a good bit of filing couldn't fix, but due to being impatient and forgetting to bring some of the proper tools to the place I would be doing the work, I ended up doing a kind of jerry-rigged, eyeballed job. The hole itself is pretty ugly, but that's not really a problems since it still looks completely light tight around the edges where the lens passes through it (and if its not, Ill just throw some gaffers tape around the flange in the back), but the lens ended up being slightly off center (a bit more than 1mm in one axis, and about 2mm in the other). I dont think this should be a problem, but would someone who knows better than me be able to tell me if I should be more worried? the lens is a 210mm Schneider, which I'm hoping has enough coverage for it really not to matter on a 4x5. Id rather not spend the extra $20-40 on a new lens board if possible, so if it isn't a problem that would be a relief.

 

[B.S.Kumar]

Don't worry.

 

[koraks]

I dont think this should be a problem, but would someone who knows better than me be able to tell me if I should be more worried?

You can reason it out. The off-centered hole basically means the front stand will be shifted by 1 or 2mm and there will be an 'automatic' fall or rise of 1 or 2mm. When framing a photo, you will automatically correct for this. You'll never even notice.

 

[garpet]

You can reason it out. The off-centered hole basically means the front stand will be shifted by 1 or 2mm and there will be an 'automatic' fall or rise of 1 or 2mm. When framing a photo, you will automatically correct for this. You'll never even notice.

awesome! That's what I though, but I just wanted to make sure. Also, one slightly off topic thing: when loading the film into the holders, its seems nearly impossible not to touch the emulsion at least lightly. How the is one supposed to avoid getting their finger prints on the negative?

 

[koraks]

I always grab the film only by one edge. Never got any fingerprints. Just ensure your fingers aren't overly greasy; wash & dry before loading film. It'll be fine. Regular photographic film has a pretty tough supercoat that avoids most of these issues.

 

[Alan Edward Klein]

I had a couple of used lenses I bought where the centering was off a lot. I was told it wouldn't change much, but I replaced it with a center-holed lens board. Don't you want the lenses in the middle so you can start from an initial setting each time you set the camera up for shooting?

Regarding finger prints, I wash and dry my hands thoroughly to get rid of any grease, sweat, and skin oils before loading up the holders with film. I do touch the emulsion at the edges, but haven't noticed any harm.

 

[Rick A]

awesome! That's what I though, but I just wanted to make sure. Also, one slightly off topic thing: when loading the film into the holders, its seems nearly impossible not to touch the emulsion at least lightly. How the is one supposed to avoid getting their finger prints on the negative?

Just before loading or unloading, wash your hands with hot soapy water and rinse thoroughly, as hot as you can stand. Dry with lint free towel. I've been doing this for years and have yet to leave fingerprints.

 

[Alan Edward Klein]

How about using alcohol like 91 percent isopropyl?

 

[loccdor]

People who need extremely clean fingers (such as those who play instruments involving touching rotating glass) do soak their fingers in isopropyl alcohol. It works well. Definitely dries out the skin though.

 

[Kilgallb]

I just got a Shenhao 4x5 and ordered an offset recessed lens board. Don't do that. My 90mm super angulon with a Copal 0 shutter won't work off centered as the wall of the recessed lens board bangs against the f-stop controls or the shutter lever. Get the centred board.

 

[ags2mikon]

I have deliberately offset the jaws on the lathe to offset the hole 12mm to give me more rise or shift on some of my Horseman boards.

 

[abruzzi]

I just got a Shenhao 4x5 and ordered an offset recessed lens board. Don't do that. My 90mm super angulon with a Copal 0 shutter won't work off centered as the wall of the recessed lens board bangs against the f-stop controls or the shutter lever. Get the centred board.

some recessed lens boards I think are offset specifically to give easier access to controls. It sounds like your shutter has controls most of the way around the shutter, but many have the controls within less than 180 degrees around the shutter. For those the extra space to use the controls is helpful.

 

[wiltw]

If you stop and think about the fact that most large format lenses have an image circle deliberately larger, to permit shifts left/right and rise/fall mobements (a much larger offset) to preserve the parallelism of verticals (and horizontals) while obtaining desired subject framing, you realize that being 'off center' by one or two or three millimeters is merely using the lens within its original designed parameters, and absolutly nothing to give a moment of thought about!