Thoughts on centering a lens on a flat bed view camera?

[Greg]

I use a whole plate Chamonix view camera. My 105mm f/8 FUJINON SW and my 600mm f/12 Fujinon T both cover the format but just barely, and I mean just barely. I swear that if the lens is 2 degrees off center axis, one or two corners will not be covered by a sharp image. Lens has to be "perfectly" on center axis with the back. GG is full and does not have its corners cut off. Closing the lens down and looking through it to see if you can see the corners of the GG doesn't work. My thoughts are to mount a mirror onto the back of a blank lens board. Then get a very, very small LED flashlight that can be placed exactly over the center of the back of the GG aimed towards the front lens board. Its image will be reflected back onto the rear GG. The reflected beam of light should show itself onto the GG. Once I adjust the front standard to have the reflected beam of light fall exactly on the LED light, the lens should be perfectly on center to the back. Does this make sense? Having trouble finding a very small LED flashlight. Also have to figure out a way to temporally "attach" it to the center of the GG. Mounting a small thin mirror to the back of the lens board and being perfectly parallel to the lens board I have solved.

Or is there some other way that I have overlooked to get the lens to be perfectly OC relative to the back of the camera?

thanks in advance

[Tin Can]

Perhaps this magnetic mount mini LED 90 degree flashlight will work for you. https://www.fenixlighting.com/product/fenix-ld15r-right-angle-flashlight/

I bought one last month and now i use it everywhere. Including to do something like you want to do.

But a laser may work better.

[ic-racer]

I use a laser to align the front standard detents on my view cameras. I bounce off a microscope slide attached to the front of the lens, then remove the lens and bounce off the ground glass. The marks should bounce back to the same place.

Once your laser is perpendicular to the rear, align the laser to the center of your ground glass, then put the lens on the camera with the lenscap and a piece of tape on the center of the lenscap. Adjust the lens so the laser points to the center of the lenscap.

I have always centered my minimal-coverage lenses in the field by looking in the 4 corners of the ground glass. Curious why this much simpler way is not working for you.

[minh0204]

I have always centered my minimal-coverage lenses in the field by looking in the 4 corners of the ground glass. Curious why this much simpler way is not working for you.

Wouldn't it be too dark in the corners to actually make sense of the coverage though? Also OP's Nikkor has a larger than 8x10 circle of illumination but much less useful sharpness, so checking the corners might not be as useful as with other lenses?