TK23 GG with Wide Angle Lenses

[robert lyons]

hi i use a tk 23 and recently rented a 75mm lens and felt there was quite signifiant light fall off on the gg. i normally use a 150mm lens and have no problems so i am wondering what is the best solution to "brighten" the gg? the camera has the regular Linhof gg that was sold with the camera. thanks for your opin

[Bob Salomon]

The Linhof Fresnel works very well.

But that will not eliminate the need for a center filter if the fall off on the film bothers yoy or if you are doing much movements.

The fresnel comes with a spring clip to let it be installed or rremoved quickly.

[Howard Slavitt]

I've found for my Horseman 2 x 3, that Bill Maxwell's fresnels work wonders. His phone # is (404) 244-0095; address is Maxwell Precision Optics; P.O. Box 33146; Decatur, GA 30033-0146. Also, for 2 x 3, there's absolutely no need to use a centerfilter with a 75 mm lens -- at least not the two I've used.

[Brian Ellis]

I'm not an optical expert but I've used fresnel screens and read about them. From my reading and somewhat limited experience (occasionally but not frequently using a 90 mm lens on a 4x5 camera equipped with a fresnel screen)the fresnel can actually make it more difficult to compose and focus with a wide angle lens unless the fresnel is designed for the approximate focal length lens being used. If Linhof makes a fresnel for your 75 mm lens (or something close to it) on your camera then I think that probably would be the best choice, particularly when it's easily removable for use with other lenses, as Bob says it is. However, if it's just a generic fresnel I'd forget it and get a Bosscreen instead. The Bosscreen isn't technically a "bright screen" since it doesn't make the image any brighter. What it does do is spread the image out evenly on the ground glass, eliminating or at least greatly minimizing the bright circle surrounded by darkness that you get (or at least that I got) with a generic fresnel and a wide angle lens. Don't be put off by the theoretical horror of the wax in the Bosscreen melting at high temperatures. I've used mine for years in the Florida and southwest summers without a problem.