I use a Sinar F, usually with 6x9 or 6x12 rollfilm holders. Being that I'm a wide-angle aficionado, being able to use a 47/5.6 Super Angulon (pre-XL) and a 65/5.6 SA was a requirement of the setup. I have installed that lens in a cheapie recessed lens board, and with the bag bellows it focuses easily without having to do anything inconvenient like moving the standards to one side of the tripod mount.
But there is one significant pain the butt with that lens: I couldn't see anything more than the central spot. The ground glass on the Sinar is deeply recessed, and getting to the edges of the frame with a loupe, considering that the loupe had to be pointed at a shallow angle into the lens, was nearly impossible.
Sinar makes a Fresnel and I have a couple of them. I find that with lenses shorter than 90, it causes a range of visual artifacts, such as ghosted images at the edges, the render it useless for the 47 and the 65. It was, of course, probably optimized for something like a 120.
After a lot of research, I finally bit the bullet and bought a standard Hi-Lux screen from Bill Maxwell. This is (yet another) mini-review of that screen and how it works on a Sinar.
The screen comes in two parts. The working part is a plastic focus screen with a ground surface on one side and a micro-Fresnel on the other. The ground surface is, I think, molded--it shows none of the surface damage that comes with grinding or acid etching use for standard glass focus screens. The micro-Fresnel is just that--in a 4X loupe, the Fresnel lines are virtually invisible. They do not interfere with focusing in the slightest. Because the frosted surface is where it usually is, this installs at the same plane as regular ground glass, without any extra fiddling. Some cameras put a Fresnel on the front side, and calibrate for the change in light path. This screen will require calibration to be accurate with those cameras. For cameras where the ground glass sits on hard stops, however, it's a drop-in replacement.
To protect the Fresnel (which faces the user), the second part is a glass cover. The markings are printed onto the cover glass. Mine is a grid with outlines for roll-film formats, which is what I ordered. Other markings are available. You can also make your own markings using a Sharpie pen on the backside of the cover glass. Make a line, let it dry, make another line, let it dry, and repeat until it looks right. Use a fine-point Sharpie and a proper straightedge like a drafter's triangle.
The two parts are sandwiched together and mounted in place of the factory ground glass. The sandwich is a bit thicker. The Sinar clips were fine without modification, but the Sinar Fresnel holder is now a fiddly fit because the new screen consumes some of the space under a clip that the Fresnel needs. In practice, it's not a problem because I doubt I'll ever use the Sinar Fresnel again.
Maxwell makes a screen optimized for very short lenses, but I find that I am now able to view the 47 reasonably using this standard screen.
"Reasonably" means "fighting chance." Before, I couldn't see well enough with that lens to compose the image--now I can compose even in dim light. I can also focus using a loupe right to the edge of the frame. I would say that the 47 is about as good as a 180 was using the standard screen. (And this with a lens that has a two-stop falloff even at f/22.) I can even see the limits of coverage on that lens, which is a very soft edge at f/5.6. In the dimness of my living room, I found that I could actually use that lens without frustration.
A 180 on the Maxwell screen shows no falloff in light intensity on the screen whatever. The scene is evenly illuminated across the screen.
This is a real option for those who want to use ultra-wide lenses that are nearly impossible to see outside the central spot on a standard screen. At just under $300, it's not cheap, but I've sure spent more and gotten less.
Rick "highly recommended" Denney
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Originally Posted by Mike1234
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