lens board

[sean yoon]

Hi
I am really new to Large Format Photography
I just got canham 5x7, roll film back and many lens from my father.
I've used 35mm SLRs for several years, so i just really basic stuff about photography.

I've been doing some test shots with LF camera, and i noticed that some of the lens that i got do not have lensboards attched to them. I am wondering if there are some ways to attach to lens board to the lens. Is it okay if i just attach them by locating the lensboard in the middle of the lens BY EYE? (because i thought that the lensboard should be exactly in the middle of the lens)
Does it make any difference, if its a bit off since i am trying to do it be eye?



thanks

[MIke Sherck]

Sean, I'm your long-lost brother! Tell dad I'll be home for Christmas! :)

Large format lenses come in shutters of different sizes. Some of the more common sizes for modern lenses are 0, 1 and 3 (from smallest to largest.) older lenses may come in size 5 shutters as well. Each size shutter requires a different sized hole in the lensboard (these things are reasonably standardized nowadays, but it wasn't always so.)

Most shutters are held to the lensboard by one of two methods: some older shutters screw into a mounting ring, which is itself screwed to the lensboard. The more modern method uses a retaining ring which screws onto the shutter from the back, "sandwiching" the lensboard between the shutter in front and the retaining ring on the back. Often, the lenses rear element must be first unscrewed from the shutter, the shutter fit into the hole in the lensboard, the retaining ring screwed onto the rear of the shutter (which projects a little bit through the hole in the lensboard, then finally the lenses rear element is screwed back into the shutter.

You can mount a lens to a lensboard yourself, but you need to exercise caution, particularly when you have the lenses' rear element removed. The shutter blades will be exposed and they are *very* delicate. Don't even sneeze on them! Retaining rings have notches along the outside edge, intended to be used by a special wrench (called a lens wrench by some.) Having the appropriate lens wrench is helpful and less dangerous than what I do (stick the blade of a screwdriver in one of the notches and turn it,) and is recommended.

Good luck with your new camera! It's a good one. I'll be expecting one of my own come Christmas morning... :)

[James E Galvin]

Since one of the things done with a large format camera is to move the lens to the side or up and down (shift and rise), it doesn't matter all that much where "0" is. I have intentionally mounted 1/4 inch off center to make it easier to get to the shutter controls (in a recessed board). By eye should be plenty good enough. You could draw diagonals fron corner to corner to get the center. I'd say there is little to be gained by getting closer than 1/8 inch.

[sean yoon]

Thanks for answering my questions.
I got all these great equipments to use, and I am getting really busy reading books about Large Format.. :)
So, I guess I will test these lens out