John Hollenberg
14-Sep-2003, 18:49
In the spirit of giving back to the large format community, I am posting my experience installing a custom focusing screen from Maxwell Precision Optics. I was unhappy with the Wista stock screen because while it is quite bright, it is a VERY directional screen. If I moved my head a bit from the optical axis, the screen would darken (worst with wide angle lenses). When I put a 90 mm lens on I found it almost impossible to focus.
In talking with Bill Maxwell, I learned that I could install the screen myself. I was previously under the impression that the fresnel was under the ground glass for this camera and so was concerned about getting correct focus point. However, Bill told me that he was familiar with the Wista and the fresnel was outside the ground glass.
Following his directions, I removed the cover glass and popped out the old screen. Since the new screen was not the exact size of the old one, I removed the strips on either side which held it in postion and replaced them with some black rubber material he had sent along. After cleaning the cover glass with Windex, I reinstalled it.
Compared to the stock Wista screen, the Maxwell screen isn't quite as bright, but it is MUCH less directional. The fresnel lines are very fine, about like those on the Tachihara I previously owned. It is more directional than the Tachihara screen, but also much brighter. I would say that it is probably the best compromise between brightness and directionality. I had no problem focusing a 90 mm lens, and the image was relatively even across the field--not much of a "hot spot" (the stock Wista screen was terrible).
Conclusion: while the screen isn't cheap, I am very happy with it so far. It is better than either the Tachihara or Wista stock screens by a significant margin.
In talking with Bill Maxwell, I learned that I could install the screen myself. I was previously under the impression that the fresnel was under the ground glass for this camera and so was concerned about getting correct focus point. However, Bill told me that he was familiar with the Wista and the fresnel was outside the ground glass.
Following his directions, I removed the cover glass and popped out the old screen. Since the new screen was not the exact size of the old one, I removed the strips on either side which held it in postion and replaced them with some black rubber material he had sent along. After cleaning the cover glass with Windex, I reinstalled it.
Compared to the stock Wista screen, the Maxwell screen isn't quite as bright, but it is MUCH less directional. The fresnel lines are very fine, about like those on the Tachihara I previously owned. It is more directional than the Tachihara screen, but also much brighter. I would say that it is probably the best compromise between brightness and directionality. I had no problem focusing a 90 mm lens, and the image was relatively even across the field--not much of a "hot spot" (the stock Wista screen was terrible).
Conclusion: while the screen isn't cheap, I am very happy with it so far. It is better than either the Tachihara or Wista stock screens by a significant margin.