Fresnel screen focus distance is different from ground glass

[Doremus Scudder]

A Fresnel does 2 things:
1 brightens the gg image
2 even outs the illumination on the gg edge to edge.

Ask the manufacturer how they propose that you do these 2 things?
Or
What they will do to your camera to achieve those 2 things?

Bob,

The Chamonix N-1 was designed poorly; the addition of the Fresnel lens was not taken into account and adding it, while brightening the image and evening the illumination, threw the focus off. The easy fix is to remove the Fresnel and use the camera with the ground glass only, similar to many other models of view camera that do not come with a Fresnel. Sure, the image is a bit dimmer, but focusing is more precise. Many prefer the standard ground glass to a screen with a Fresnel lens added.

Best,

Doremus