Fresnel and Readin Glasses: Incompatible ?

[Ken Lee]

I just purchased a 5x7 screen from Global Matter Lab as a replacement for my broken Sinar P screen.

Consisting of a fine acrylic screen, and a fresnel that sits behind it (closer to the eye than the lens), the image under the black cloth is quite bright to the naked eye, but...

Being a bit far-sighted, I wear reading glasses. With them on, I find it almost impossible to avoid seeing artifacts of the fresnel, which make it hard to see the image itself - unless I stand back quite far.

I notice that the original Sinar screen is good-old frosted glass with some rules painted on. That's all. For someone wearing glasses, is that the best way to go, or is there something unusual about the design of my new screen ?

I don't recall having this problem with my Tachihara a few years back, and it has a built-in fresnel, as I recall.

Many thanks for any help or explanation !

[Brian Ellis]

That's the problem with Fresnels and loupes or reading glasses. But some are better than others. The Maxwell screen is the best of the Fresnels that I've used. I used reading glasses and also a loupe with it and could barely see the Fresnel lines. I also used reading glasses and a loupe with the Tachihara screen and with it I could see the lines more but still was able to focus o.k. OTOH, I found it quite difficult to focus with the Ebony screen because the Fresnel lines were so obvious with reading glasses or a loupe. I think that in varying degrees depending on the particular screen seeing Fresnel lines is just one of the trade-offs you have to make for the brighter screen (though the trade-off was pretty minimal with the Maxwell). I've never heard of the company that makes the screen you bought so I can't comment on it.

"I notice that the original Sinar screen is good-old frosted glass with some rules painted on. That's all. For someone wearing glasses, is that the best way to go, or is there something unusual about the design of my new screen ?"

I think it's all just a balancing act, Fresnel screen = brighter image with lines, ground glass = no lines but dimmer screen especially with wide angle lenses. The question is how bad are the lines and how dim is the image with the particular Fresnel or ground glass. Just as some Fresnels are better than others, some ground glasses are better than others too. The Linhof ground glass on my Technikardan was terrible, the ground glass on my Deardorff was very good. Others have said Satin Snow ground glasses are very good also, I've just never used one.

A compromise you might consider is a BosScreen. These screens aren't Fresnels so there are no Fresnel lines but they give the appearance of a brighter image by spreading it out evenly across the entire ground glass. The pros and cons of these screens have been discussed extensively here and other places so I won't go into them again, if you search here or Google you can find lots of information. I used three or four BosScreens in different cameras and was very happy with them though I'd still choose the Maxwell if the roughly $100 price differential wasn't critical.