Fresnel grooves toward lens or not?

[bevdig]

My Linhof Technika has a Fresnel lens behind the ground glass. The grooves are on the inside and touching the ground glass. Is this correct or should the grooves be on the outside, facing the user?

[grat]

Depends entirely on the camera, but in general, yes, this is correct.

The rough side of the ground glass is the focusing plane. It should be the same distance from the lens as the film plane when you have a film holder in the camera-- so moving it around is usually a bad idea.

The fresnel can face either direction, as all it's there for is to try to "straighten" the diffused light from the ground glass, but you really don't want to be sliding your loupe across those ridges, so the typical orientation is to put the grooves against the smooth side of the ground glass.

[Larry H-L]

There are several variations on fresnel use, some outside and some inside the ground glass. As you describe yours, in general the grooves face inward toward the ground glass and toward the interior of the camera, smooth side toward you the photographer.