Vignette on Linhof 4x5 reflex finder

[Bob Salomon]

Nate,

Over the years Linhof has had many Fresnels. They keep updating them but they only sell one type for the 4x5 and larger cameras. And these are corrected for the commonly used range of optics used for that format. One way that you can tell is how well the image snaps in and out of focus. If the lens is too short for the Fresnel it just does not have that in focus snap while you are focusing. And if the Fresnel is not the proper one for the lens then the image will also tend to black out with small movements of the eye across the screen.

For the M679 and Techno cameras which are 6x9cm Linhof introduced at the last Photokina a new proprietary gg and Fresnel type system which is markedly brighter and more contrasty then any other system, including the old Acutte Matte screen which these replaced. But they would be prohibitively expensive for a 45 system and probably would not work well on larger formats due to the difference in focal legths used. These new screens are for 23 through 180mm lenses.

[ghoonk]

Turns out that i didn't have a fresnel. Bought three of eBay and the vignette by is significantly reduced. Thanks for the help, everyone!