Hi Everyone.

I've seen several posts in the past regarding how to check for vignetting prior to shooting. All of the solutions required a GG with cut corners. My question is, how do you check for vignetting if your GG doesn't have cut corners ? I occasionally get back a chrome with slight vignetting due to excessive movement, and yet I was unable to detect it even after stopping down to the working aperture. My Toyo 45AII comes with a very decent and bright GG so I would think that I should be able to see the vignetting when stopped down, but not so. Any suggestions ? As always, thanks in advance for your help.

-- Doug Meek (doug.meek@cardinal.com), May 15, 2002

Answers

If the back is removeable, remove the back and sight through the corners. If you don't mind doing so, take the ground glass to a glass cutting shop and have them cut the corners off for you, or use a glass cuttere to do this yourself. Alternatively, try applying varnish to the corners to make them clear and see through. Good luck, DJ.

-- N Dhananjay (dhananjay-nayakankuppam@uiowa.edu), May 15, 2002.

I don't ever have the need to do this with my setup, but I beleive looking through the lens (at the desired stop) from the front of the camera back at the GG corners will do the same thing as looking through cut corners, it's just the reverse.

-- Mateo Leyba (mateoleyba@yahoo.com), May 15, 2002.

Doug,

On one of my 8x10 lenses I kept getting vignetting and could never figure out why, because I was judiciously looking through the (cut) ground glass corners before every shot. Then I figured it out: I was adding my filter (usually red or yellow, and hard to focus with) after composing and checking for vignetting, and the filter was vignetting.

This probably isn't what is happening to you, but I thought I'd bring it up in case it rings a bell.

-- Erik Ryberg (ryberg@seanet.com), May 15, 2002.

The sure way to check for vignetting is to set the lens at the shooting aperture, and look through the lens FROM THE FRONT. If you can see all corners of the ground glass area you will be fine. This works too when using an adjustable lens shade, trying to set it at its max...

-- Per Volquartz (volquartz@volquartz.com), May 15, 2002.