Chinese Ebay ground glass

[jinsonphoto]

I just recently switched from a sinar F2 to a linhof Technikardan. The ground glass the with the linhof didnt have a fresnel attached and the Sinar's fresnel is too small so Im currently going down the rabbit hole of ground glass/fresnel research. I loved the combo I had on the sinar, it worked great, but the new (to me) Technikardan glass is just to dark (I shoot a lot at night). Anyways while researching the limited custom ground glass options I stumbled across this ebay seller. Has anyone tried these?

https://www.ebay.com/itm/Ground-Glas....c100005.m1851

Here is the description: Condition: New
Compatible with: 4x5 Camera

Description:

Bright Accurate Clear

I make ground glass for a variety of camera and formats.As far as brighter is concerned,over the yesrs I have measured a variety of focusing screens and compared them to the originals.

This includes new acid etched,hand ground,Boss Screen,current hand-ground glass,Beatty and Bright screen and my own.I measured with a Gossen Luna Pro and a probe from edge to edge.

There is a half-stop difference from old glass in most cases.Acid etched is brighter by a stop-BUT-you loose the contrast that is in hand ground glass that makes focusing easier and faster.

The only significant improvement comes with using a fresnel-BUT-it makes focusing with wide angle lenses and a loupe a real chore as the lines of the fresnel become increasingly evident.

In the end,I use a three step method which is actually different than that of any other offering.It combines everything I have learned about ground glass and to get the most amount of light with the most amount of contrast by chemcial and hand-ground methods and includes a final coating,as well.

[jinsonphoto]

However, I did find a good deal on a linhof Bosscreen, which I may just go ahead and purchase. Can anyone recommend these? Not sure I have the time or money to pony up for a Maxwell screen.

[Bob Salomon]

However, I did find a good deal on a linhof Bosscreen, which I may just go ahead and purchase. Can anyone recommend these? Not sure I have the time or money to pony up for a Maxwell screen.

The Boss Screen is two pieces of glass that sandwich a layer of wax. If the wax gets too hot it will reticulate.

Your TK, if it is no more then about 20 years old, has a silver rectangular bar on the center screw on each end of the ground glass holding clips. Those bars are the Fresnel holding clips. They swing too either side to install the Fresnel.

Do it the right way and just get the Linhof Fresnel. It will work better then the Boss without the heat problem.

[Tobias Key]

The Boss Screen is two pieces of glass that sandwich a layer of wax. If the wax gets too hot it will reticulate.

Your TK, if it is no more then about 20 years old, has a silver rectangular bar on the center screw on each end of the ground glass holding clips. Those bars are the Fresnel holding clips. They swing too either side to install the Fresnel.

Do it the right way and just get the Linhof Fresnel. It will work better then the Boss without the heat problem.

I have a Bossscreen on my Toyo that came with the camera when I bought it. If I remember correctly these screens have to be shimmed so that the wax part of screen sits in the right place, so make sure it comes with the correct shims to do this. I like the screen on mine but haven't used many different LF cameras so my opinion is not worth that much!

[Bob Salomon]

I have a Bossscreen on my Toyo that came with the camera when I bought it. If I remember correctly these screens have to be shimmed so that the wax part of screen sits in the right place, so make sure it comes with the correct shims to do this. I like the screen on mine but haven't used many different LF cameras so my opinion is not worth that much!

It is not how they are shimmed! Shims would create a focus shift!
The Boss Screen has to have the mounting points cut out so the wax layer is positioned at the correct film plane. That is why they were sold for specific camera brands!

Since the wax layer is where the image is formed it would be above the point where the ground side of a ground glass would lie. Hence cutting away part of the bottom glass to properly position the wax layer. If you added shims you would raise the wax layer above the film plane.

Bear in mind, the Boss Screen was originally made to be a grain free rear projection screen to make copies of movie and slide film. The original screen was 11x14” and for that purpose where the image was formed was immaterial. But as a camera screen it was critical!

[jinsonphoto]

The Boss Screen is two pieces of glass that sandwich a layer of wax. If the wax gets too hot it will reticulate.

Your TK, if it is no more then about 20 years old, has a silver rectangular bar on the center screw on each end of the ground glass holding clips. Those bars are the Fresnel holding clips. They swing too either side to install the Fresnel.

Do it the right way and just get the Linhof Fresnel. It will work better then the Boss without the heat problem.

[jinsonphoto]

Yes mine has the clips. I was worried about all of the potential issues with the boss screen. Can any of you recommend where to by a linhof sized fresnel? I prefer not to go the linhof route if I can avoid it (due to their price).

[Tin Can]

Bear in mind, the Boss Screen was originally made to be a grain free rear projection screen to make copies of movie and slide film. The original screen was 11x14” and for that purpose where the image was formed was immaterial. But as a camera screen it was critical!

Good to know and that explains a couple mysteries I have had. Thanks!

[jinsonphoto]

Hey does anybody know about this company or there products? They are out of ohio.

https://www.ebay.com/itm/New-Linhof-...sid=m570.l1313

[Mark Darragh]

I bought one of the Chinese GG some years ago to replace the one on my Toho when it got smashed on a hiking trip. It is adequately bright even working in misty forest or dusk/dawn conditions.

I can't give you direct experience of the Linhof Fresnel/GG combo (the Technikardan I had for years only had a GG) vs a Bosscreen but I have a similar combo on my Arca F Line. I prefer the Bosscreen for closeup and macro work and use the Fresnel/GG for general work. No great difference in brightness and if I had to, I could easily live with just one of the two.

All the best