View Full Version : Lensboard outdentations

20-Feb-2008, 08:10
I bought a few wooden lens boards for my Zone VI camera on eBay. I'm planning on purchasing a lens, and potentially need a lens board, so I bought what I could find - 2 fit a Copal 0 and 2 fit a Copal 1. They were cheap, so why not.

The back side (inside the camera side) is different between the different boards. Two of them have an "outdentation" (I don't know what to call it except it's the opposite of an indentation) that fits into the hole in the front of the camera. It's like the lens board is of double thickness, and the inside thickness has a smaller dimention so that when mounted it extends into the hole. The other 2 have a little bit of one that doesn't fill up the entire hole. In other words, one type appears to have what you might call a 2 level light trap, and the other type doesn't. Is this extension into the hole necessary for it to be light tight?

20-Feb-2008, 08:25
I think you'll find out from usage, but I've never seen a difference between lensboards without and with light traps. In fact, I have leaky bellows on one camera and I don't even get ghosting. There's definitely a margin between light-leak and over-the-top-safety.

I wouldn't worry, unless you find some ghosting on your negs. best way to check is place the lensboard on the camera, with the lens closed (or the copal hole covered up) and leave a sheet of light-sensitive material (film, or cheaper, paper) in a holder. If you develop it and there's any exposure, then there's light getting through.

20-Feb-2008, 10:08
I own one board with the "outdentation" that is standard on many technika size boards. The other 9 are homemade and flat. No problems. I don't think light has figured out a way to bend around corners, yet.

20-Feb-2008, 12:29
Actually, light figured out how to bend around corners about 14 billion years ago. We know this as diffraction (not that this is relevant for the case in question; the smart-ass in me just couldn't resist) :-)

Alan Davenport
20-Feb-2008, 12:48
I have boards with and without the "outdentation" and haven't noticed any difference in performance. In fact, my heaviest lens (a 10 inch f/4.5) rides in a board that has no light trap at all, and it works fine on my Tachihara.

20-Feb-2008, 13:49
RE: diffraction

Right. Light also gets bent by gravity, but I don't think my camera is massive enough to make a significant difference.