LF Front Lens Shims

[David Hansen]

Perhaps you or the many readers out there can give me the answer and help me locate these items.
My Rodenstock 210 mm lens in a #1 Copal shutter, and my 121 mm Schneider Kreuznach in a #0 Copal shutter, need front element shim rings. Without them, the lens will not focus perfectly. Neither company cares to help, or can’t, and my lenses are not worth that much if they can’t focus sharply. These shims are 0.1 mm thick, and i need three of each (or shims that add up to 0.3 mm).
Help!!

 

[Nodda Duma]

Hi David,

check out shimstock on McMaster-Carr. I would be surprised if you can’t find what you need there.

 

[David Hansen]

Hey thanks for the tip.

I looked there and found the thicknesses I need, and one of the bores, but they are all far too wide. Need a very slim ring.

 

[Nodda Duma]

Hey thanks for the tip.

I looked there and found the thicknesses I need, and one of the bores, but they are all far too wide. Need a very slim ring.

look at their brass shim stock sheets or strips. You don’t actually need a full ring.. just 3 points of contact at 180 degrees. Done that plenty of times as a lens designer assembling prototypes.

You can use brass shims. You can minimize edge curl when you cut by stacking 3-5 layers before you cut with sharp scissors and then using the center piece.

set in place with a dab of water. Place the lens down and tighten down the retaining ring.

and welcome to the forum!