Newton rings on Bosscreen

[Roberto]

I have just received a Bosscreen for my Wista 4x5 and have fitted it on the camera without problems. Just one question arises since after mounting it slight newton rings have appeared on the glass. I want to underline that the glass has been mounted properly and no tension is p resent anywhere on the glass. When I checked that the glass was firmly in place by gently pushing on it I heard strange unknown sounds . I lately discovered the weak sounds I was hearing were probably from the wax layer detaching from the o uter glass hence forming very slight newton rings that in any way do not affect the viewing. I want to stress the fact that when I checked the glass to be in p lace I put a pressure so weak and gentle that I can not believe this is not a co mmon phenomenon. Otherwise that means the Bosscreen is a glass more delicate tha n butterfly wings. With this message I am just asking if this experience has occurred also to ther users of this focusing screen. Thanks for reading.

[Jason Greenberg Motamedi]

Sounds as if you have a faulty Bosscreen--I have used bosscreens in several different cameras and have never heard noises, and have never seen Newton rings. In my experience they are susceptable to heat, but 'normal' pressure, such as me pushing a loupe on it, is fine and shows no effects. If possible, try to return it.

[jnorman]

yeah - i tried a bosscreen and ran into the same problem - the wax between the two plates was a constant source of difficulties and i often noticed little bubbles in it. i just couldnt work with it and will never try a two-plate system again. i bought a beattie intenscreen, which i like quite a bit, though i still have to use a fresnel with it to obtain appropriate screen brightness.

[David Karp]

Roberto,

I have had a Bosscreen for a little over one year. I have never experienced the problems you describe. I love using this screen, the only hassle is to make sure it does not get too hot. Mine has been used in the cold, down to about 30 degrees F, with no problem. Very bright and even image. It works with wide angel lenses, even without a Fresnel screen. I would not want to trade back to a standard ground glass. I think you probably have a defective unit.

[Roberto]

Yes, I was fooled by a stupid thing just as well! The newton rings comes from the original plain glass from Wista that keeps the whole Bosscreen in place. Therefore the rings are not in the Bosscreen . I am very glad everything is ok , since the cost and time needed to get the thing. I only wonder what was the source of the rattling...but since everything looks OK who cares. Thanks to all who have given an answer.

[Huib]

Roberto,

You have to replace the standard Wista groundglass with the bosscreen. You did that?

Huib

home.plex.nl/~hsmeets

[David Karp]

Roberto,

Double check. On my camera, you completely remove the standard groundglass and replace it with the Bosscreen. It is not like an extra Fresnel. There is no extra glass holding it on. My guess is that your camera does not require the original glass plus the Bosscreen.

[Roberto]

Yes, I left the plain glass from Wista in place (not the GG, just the thin glass) for two reasons: - To give extra protection when using the loupe and/or during transportation - to ensure proper thickness so that the glass holder and the foam can keep everything in place. Of course I might be wrong and could place a thicker piece of foam to hold the Bosscreen. I don't know though. Is this the solution you all used?

[Roberto]

... and of course my name is not baluba but Roberto Manderioli. Sorry for the mistake!!