Cut corners of the ground glass.

laz · Sep 2, 2005

I'm going to order a Satin snow ground glass for my new 8x10 Korona. The glass currently has cut corners; why is that?
My first thought was that it has something to do with air pressure caused by compression of the bellows, but on reflection that doesn't make much sense.

Bottom line, should I order cut corners? And if Satin Snow himself is reading this do you need measurments for a 8x10 Korona? (if not I'll order immediatly from here at work!)

-Bob

Troy Ammons · Sep 2, 2005

laz127 said:
I'm going to order a Satin snow ground glass for my new 8x10 Korona. The glass currently has cut corners; why is that?
My first thought was that it has something to do with air pressure caused by compression of the bellows, but on reflection that doesn't make much sense.

Bottom line, should I order cut corners? And if Satin Snow himself is reading this do you need measurments for a 8x10 Korona? (if not I'll order immediatly from here at work!)

-Bob

I think it is to let the air in and out. its pretty common.

Dave Parker · Sep 2, 2005

There are two trains of thought on the cut corners, 1st is of course to help air evacuated from the bellows when closed, the second is to check for vignetting on your lenses, the asumption being, if you can see the full aperture of you lens when stopped down you will not be vigenetting. One other thing, many of the wood cameras require clipped corners to actually fit the back of the camera because of the way the dados or corners were made.

And yes, I have the Korona Measurments and have done several screens for these cameras.

Thanks, Let us know if we can help

Dave Parker
Satin Snow Ground Glass

Daniel Grenier · Sep 2, 2005

laz127 said:
.....Bottom line, should I order cut corners? ...

Bottom line? No.

Every single square mm must be seen IMO - especially the corners which are far more important than given credit for. I had cut corners on my 8x10 and replaced the GG with a full GG. Much better! The cut corners where to, supposedly, let air out when you close the bellows and draw the bellows etc... but I don't find that to be of any consequence to me.

Cheers

Dave Parker · Sep 2, 2005

Bob,

Is the camera you purchased from Matt?I think remember reading that somewhere, if so, you might check, because it may already have one of our screens in it.

Dave

laz · Sep 2, 2005

Satinsnow said:
Bob,

Is the camera you purchased from Matt?I think remember reading that somewhere, if so, you might check, because it may already have one of our screens in it.

Dave

Yup, that's the one. I'm embarrased, but you'll have to believe me that I didn't look all that close last night, I'm new at this and well, you get the picture (pun intended)
-Bob

Dave Parker · Sep 2, 2005

laz127 said:
Yup, that's the one. I'm embarrased, but you'll have to believe me that I didn't look all that close last night, I'm new at this and well, you get the picture (pun intended)
-Bob

No reason to be embarrassed, just wanted to make sure you did not spend money you might not need to...I will be happy to sell you one, but don't want to see you duplicate your efforts. If I can ever help, just drop me a note.

Congrats on your new camera have fun and good shooting.

Dave

sattler123 · Sep 2, 2005

That's Dave for you - honest, even if he risks losing the sale. I would encourage you to nevertheless buy a spare Ground glass from Dave - you never know. Given the price of Dave's Satinsnow glass, it is really a no-brainer. I have back-up glass for all my LF gear - and yes, all my ground glasses are from Dave.

David A. Goldfarb · Sep 2, 2005

I prefer cut corners, because with a wide lens you can't always see what's happening in the corners very clearly on the groundglass anyway (meaning you have to sort of look at the groundglass, then look at the scene and extrapolate to see if anything distracting is happening in the corners), and cut corners make it easy to check for vignetting.

If you don't have cut corners, you can also check for vignetting from the other end, by looking through the lens and seeing if you can see the corners of the groundglass. Yet another option on most cameras is to remove the back and check the corners that way when needed.

Bob F. · Sep 2, 2005

Apart from letting the air out (though I doubt many cameras are sufficiently air-tight for it to be an issue) it allows you to make all your movements, stop down to your working aperture and look through the corners. You should see the full circle of the aperture blades. If you see an ellipse, it means you have exceeded the coverage of the lens and need to do something about it. Such vignetting is not always obvious on the screen, especially in low light.

If you are new to LF in general and have not found it already, pop along to www.largeformatphotography.info for more data than you can shake several sticks at.

Cheers, Bob.

matt miller · Sep 2, 2005

The GG with the camera is one I bought from Dave. I prefer cut corners to check for vignetting. I feel that I can anticipate what will and will not show up in my corners more comfortably than I can anticipate the edge of the circle with some of my lenses.

laz · Sep 2, 2005

Bob F. said:
If you are new to LF in general and have not found it already, pop along to www.largeformatphotography.info for more data than you can shake several sticks at.
Cheers, Bob.

Gee, but it's so much fun to shake sticks at APUGers

Yes, I started visiting the site before I purchased my 8X10. Actually printed out a bunch o' stuff.

I'm the social sort, but, I'll be a good boy and study my lessons on LF

Cut corners of the ground glass.

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