plastic focusing screens

[severian]

Has anyone made a plastic focusing screen? I believe that one is supplied with the Wehman 8x10 camera. What materials are used? Is it regular plexi with a coating or an applied plastic? Got no response from Wehman. I have tried regular plexi with a frosted peel off acetate that I applied. It works but I'm looking for a better way

 

[Dave Parker]

What better way are you looking for, if your plexi with the peel off works?

I am not surprised you did not get a response from Wehman, as most of us in the industry pretty well keep our secrets to our selves....

What exactly is it you are trying to achieve that you have not already achieved?

Dave Parker
Satin Snow Ground Glass

 

[severian]

I would like it to be as clear and bright as a Satin Snow groundglass but be unbreakable.

 

[Dave Parker]

In the world of photography,

There is no such thing as Unbreakable, sorry, there are going to be trade offs at each stage of the game, Plastic becomes brittle over time due to the impuratives in the air they are exposed to..

Good luck, and let us know if you find something.

Dave

 

[sanking]

I would like it to be as clear and bright as a Satin Snow groundglass but be unbreakable.

Well, I have a 5X7" plastic (acrylic, lexan ?) ground glass that is ground glass on one side and fresnel on the other. Someone gave it to me about ten years ago and I have never been able to locate a source or find out who made it. If I could buy this material in various sizes it would be on every one of my cameras.

As is, I would kill for the piece that I have, which is on my 5X7 Nagaoka. It gives a very bright image, evenly illuminated over the whole frame, and is of course unbreakable.

Sandy

 

[Dave Parker]

The myth of lexan being unbreakable is just that, a myth, we did alot of testing with various plastics and all of them are breakable, depending on what you subject them to, and when dealing with plastics, they are not 'ground glass' but are an alternative to ground glass and they do work for a great many people, glad you have a screen that works for you Sandy.

Dave

 

[sanking]

The myth of lexan being unbreakable is just that, a myth, we did alot of testing with various plastics and all of them are breakable, depending on what you subject them to, and when dealing with plastics, they are not 'ground glass' but are an alternative to ground glass and they do work for a great many people, glad you have a screen that works for you Sandy.

Dave

Dave,

Yes, unbreakable is not correct in reference to plastics such as acrylics and lexan. If you flex them enough they will for sure break. However, in practical use on view cameras I doubt anyone has every broken one. And who among us has not broken a ground glass? Or two or three, or more?

I have regular ground glass on most of my cameras, but the piece of plastic that is frosted on one side and fresnel on the other is just something to die for. And it is very bright, and very evenly illuminated

Sandy

 

[Dave Parker]

Sandy,

It was not a critizim at all, that is not what I meant, and I am glad you found a screen that you like, actually I have several thousands square inches of various plastics around my shop that can, and do work very good for screens, they are very expensive, quite a bit more than the average user will pay, which is why I went to work developing the process I did, but again, not saying anything bad at all about plastics, its good stuff, just a bit expensive and most plastics will shift color(albeit slight in certain materials) in a couple of years, we are always doing R&D to see if there is something better, but again, not saying anything bad..

Dave

 

[severian]

Sandy,
I've never seen or heard of the type of screen that you describe on your 5x7. I seems that that is the answer. Someone, somewhere must make this stuff. I gotta get this on my camera.

 

[David A. Goldfarb]

If there were a plastic that didn't break or warp easily, was lighter than glass, and didn't flex, it would be a real boon to ULF users.

 

[Dave Parker]

Good luck severian,

If Sandy can't find someone who makes it after the number of years he has been in the business, I can almost guarantee you the rest of us are out of luck LOL

Dave

 

[sanking]

Sandy,

It was not a critizim at all, that is not what I meant, and I am glad you found a screen that you like, actually I have several thousands square inches of various plastics around my shop that can, and do work very good for screens, they are very expensive, quite a bit more than the average user will pay, which is why I went to work developing the process I did, but again, not saying anything bad at all about plastics, its good stuff, just a bit expensive and most plastics will shift color(albeit slight in certain materials) in a couple of years, we are always doing R&D to see if there is something better, but again, not saying anything bad..

Dave

Dave,

I did not see or assume any criticisim in your comments. I am simply describing a particular type of plastic, i.e. very fine ground surface on one side, fresnel on the other, that has proven to be a very superior type focusing screen on my 5X7" camera. Unfortuantely, I have no idea who made this type of plastic, and I have tried very hard to locate a source.

My comments were made in response to the original message. They are not meant in any way to compare the product you produce, which by all accounts is an excellent one, with plastic type ground glasses.

Sandy

 

[John Kasaian]

What is a gg if not a place for the aerial image to project upon? Wax paper, if it were rigid enough would work but not very well. The optical qualities of the gg that foster a bright image for focusing is what matters most to me, however the gg is a weak link because it is fragile.

If my gg was to accompany me on a 'suicide mission' where breakage was a likelyhood I'd:

1) Make a gg protector (I think directions are knocking around in the archives somewhere)

2) Take a roll of cellophane packing tape to immobilize any crack(s)

3) Take along a sheet of lexan and a screwdriver as a back up. Sandy's lexan/fresnel sounds like it wouldn't be that hard to replicate. I used to do a lot of work with lexan and I can't see how making one would be a problem (of course this was a long time ago! I hate it when I refer to anything I've done as being 'a long time ago'---makes me feel old!) But I can't see (ha-ha) how it would rival a proper gg in brightness, though it might come close. A very real downside of using plexi/lexan is scratching and checking(if thats the correct term.)

CTTOI, any of these suggestions would be good insurance to have along on a road trip.

My 2-cents

 

[lee]

I have a plexi screen for my 8x10 that I bought off ebay several years ago. I replaced it because it was not sharp enough. It was hard to focus with. And if anyone wants to buy it I will sell it for what I have in it. $40. I now use Satinsnow glass in my 45 57 and 810 cameras. If interested just PM me.

lee\c

 

[j_landecker]

Well, I have a 5X7" plastic (acrylic, lexan ?) ground glass that is ground glass on one side and fresnel on the other. Someone gave it to me about ten years ago and I have never been able to locate a source or find out who made it. If I could buy this material in various sizes it would be on every one of my cameras.

As is, I would kill for the piece that I have, which is on my 5X7 Nagaoka. It gives a very bright image, evenly illuminated over the whole frame, and is of course unbreakable.

Sandy

This sounds like a Beatty Intenscreen or Maxwell screen. I think Calumet also sold a screen like this. I think a major drawback with plastic is its tendency to warp under stress or if it gets warm on one side (i.e. in the sun).

 

[sanking]

I have a plexi screen for my 8x10 that I bought off ebay several years ago. I replaced it because it was not sharp enough. It was hard to focus with. And if anyone wants to buy it I will sell it for what I have in it. $40. I now use Satinsnow glass in my 45 57 and 810 cameras. If interested just PM me.

lee\c

Lee,

There is obviously a difference in quality in the way ground glasses are made, whether from plastic or glass. The plastic screen that I have is very, very bright and the image is as sharp as anything I could get on glass.

On the other hand, there are also a lot of poor quality grond glasses out there made from glass.

The point here, it seems to me, is not a comparison of a glass and plastic focusing screens, but the simple fact that for whatever reason some people find advantages in plastic, primarily because of the fragility of glass. Plastic obviously has disadvantages, in that it scratches easily and is subject to warp.

In other words, there is probably a good market out there for high quality plastic focusing screens, just as there is for high quality glass screens.

Sandy

 

[lee]

Sandy,

I agree with you. This one may just need to be ground a bit with a finer grit. I don't know I don't use it since I got the Satinsnow gg screens. They are an excellent product in my estimation.

 

[lee]

in my opinion, what the large format and Utlra large format users need is ground glass protectors for all sizes of formats. I have one for the 45 and 810 but the 57 is hard to find or impossible to find or I would have one already. I have not broken any ground glass but I have scratched a few in my time. just my 2 cents worth.

lee\c

 

[Jon Shiu]

Well, I have a 5X7" plastic (acrylic, lexan ?) ground glass that is ground glass on one side and fresnel on the other. Someone gave it to me about ten years ago and I have never been able to locate a source or find out who made it. If I could buy this material in various sizes it would be on every one of my cameras.

As is, I would kill for the piece that I have, which is on my 5X7 Nagaoka. It gives a very bright image, evenly illuminated over the whole frame, and is of course unbreakable.

Sandy

The Tachihara camera uses a ground glass/fresnel piece and a separate glass to protect the surface. Perhaps Midwest Photo Exchange would have them?

Jon

 

[Dave Parker]

If I remember right, many of the new LF cameras use a plastic fresnel only, with a clear glass protector over them, I have been replacing alot of them this year.

Dave

 

[Loose Gravel]

Funny thing, in over 20 years of looking at ground glass, I have never broken one. Knock on wood. I do care a spare.

 

[Dave Parker]

Funny thing, in over 20 years of looking at ground glass, I have never broken one. Knock on wood. I do care a spare.

Well now that you have made that proclimation LMFAO and if your luck runs like mine, we are here just waiting to help out...

LOL

Dave

 

[sanking]

If I remember right, many of the new LF cameras use a plastic fresnel only, with a clear glass protector over them, I have been replacing alot of them this year.

Dave

Which new LF cameras come with a plastsic fresnel only?

And why do they need to be replaced?

Sandy

 

[Dave Parker]

Sandy,

I know for a fact the Ebony, and the Grandolfi come with just a fresnel and a clear glass viewing protector over it, I just had a friend here about a 1 1/2 months ago, that brought his Grandolfi, and I was quite surprised to see his screen just a subtle fresnel, with a clear protection screen over it, and have just shipped a screen to an Ebony owner who had the same set up...

As far as why they need to be replaced, because a great many people, like me, do not like the concentric lines that a fresnel exhibits on the focusing screen, I personally would take a glass screen a bit dimmer over a fresnel a bit brighter, if I don't have to put up with the magnification lines.

But that is just me.

Dave

 

[sanking]

As far as why they need to be replaced, because a great many people, like me, do not like the concentric lines that a fresnel exhibits on the focusing screen, I personally would take a glass screen a bit dimmer over a fresnel a bit brighter, if I don't have to put up with the magnification lines.

But that is just me.

Dave

I too am bothered by the concentric lines of a fresnel, but on the other hand you get greater overall illumination of the image on the ground glass.

Overall, it is pretty much a wash for me. I have gone back and forth on this for over two decades so whatever position you take I agree with you.

Sandy