Focusing Screensgreenspun.com : LUSENET : Large format photography : One Thread
I currently have a super speed graphic camera with the original groundglass focusing screen. I would like to get an intenscreen or a brightscreen. Has anybody used these screens? Are they worth the 200+ price tag? Which screens are the best for 4x5?
-- Jon Miller (firstname.lastname@example.org), May 09, 2000
If I remember right, the Super Graphic came with a fresnel/ groundglass combination and the orientation of the fresnel is on the lens side. Are you saying that the fresenl is not bright enough or is it missing altogether? If its missing, your focussing plane is not set at the film plane i.e., you're likely to get focusing errors. I've used the Beattie intenscreen. Its basically pretty much like a fresnel, except it is in one piece i.e., it is one piece of glass with the ground glass on one side and the fresnel pattern on the other. The image is noticeably brighter with a considerable reduction in the hot spot but focusing on extremely fine detail is sometimes difficult.
The problem with plain ground glass is that a fine ground glass will allow focus on fine detail but produces a pronounced hot spot while a coarse ground glass produces less of a hot spot but makes focusing on fine detail problematic. A fine ground glass with a fresnel to even out the brightness works well but the lines of the fresnel are sometimes problemtaic when focusing on fine detail. Another option which I haven't used but have heard good things about is the Bosscreen, which you probably should check out if you're on the market for a focusing screen (said to eliminate some of the problems associated with fresnels but seems a little delicate as far as temperature is concerned - there is more information on the LF page reegarding Bosscreens). Hope this helps. DJ
-- N Dhananjay (email@example.com), May 09, 2000.
This has always been a topic of heated debate. Working with a any kind of a Fresnel brightening screen is not without it's downside. It's pretty subjective. One thing I will caution you about is that the business of installing one between the gg and the lens can create focus problems if care isn't taken to calculate the adjusted position of the gg. I once fell into this trap and wasted a vacation and a lot of film. Some people put the screen behind the gg where it won't get you into trouble. That way it can also be easily removed if you don't like it. If you're curious, you might check out my article in ViewCamera magazine (Nov./Dec. 1996) and read about a procedure for film testing gg/film plane alignment. Good Luck.
-- Robert A. Zeichner (firstname.lastname@example.org), May 09, 2000.
I have a Linhoff Super Screen in my Busch Pressman. It replaces the ground glass and costs $75.00. You can get one from B&H or Adorama.I don't know if it will fit in your Graphic, but they will be able to tell you. For my camera, it was the same size and thickness as the gg and so fit easily. It works very well. Wide open, you can see from corner to corner and most of the time I don't need to use a hood. the only difference is you have to be a little more careful when you focus. It doesn't snap into focus like the gg, but I got used to it quickly and for me it is worth the extra time to be able to see the whole image.
-- John Laragh (email@example.com), May 09, 2000.
Bill Maxwell makes excellent fresnel/bright screens. He custom designs each one for your camera and lenses you plan on using it with. As Bill will no doubt tell you if you call him, ideally, each lens should have its own fresnel. SLRs get around this problem because each lens is the same distance from the focal plane, which, of course, is not true for large format photography. Here is Bill's contact information: Bill Maxwell (404) 244-0095/Maxwell Precision Optics, P.O. Box 33146, Decatur, GA 30033-0146.
-- Howard Slavitt (firstname.lastname@example.org), May 10, 2000.