New to LF: understanding what I see on the ground glass

[GPS]

With flare you wouldn't see any bunch of pentagons, just strange shine. Later change to human ground glass to be happy.

[aduncanson]

I am not sure what you mean by "simple glass" any more than what GPS means by "human ground glass." Perhaps you are saying that your focusing screen is not ground at all? It should be.

I tried to duplicate your setup with a short, fast, tessar design lens and a ground glass with no fresnel. I don't see what you see. the bright spot on the screen is very diffuse and not at all hard edged.

I think that Ole understood half of the situation, but also that your ground glass has been replaced with un-ground.

[GPS]

I am not sure what you mean by "simple glass" any more than what GPS means by "human ground glass."
...

Ground glass that doesn't make one crazy...

[Nathan Potter]

I think Ole is correct. The GG in question is poorly ground so is in effect translucent, providing both a hazy image of the scene as well as a hazy direct view of the aperture. Possibly a poorly, home made screen. Problem will be solved by replacement with a fully ground screen. If the OP can see enough of the scene to focus using the current screen he'll be OK to use the camera.

Nate Potter, Austin TX.

[Ole Tjugen]

could also be it's just old and greasy - try warm water and dishwasher liquid before you go to the expense of replacing it. That worked wonders on my old AVUS GG, which was almost transparent. 90 years of smudge...

[Jack Dahlgren]

Yep, the picture tells the story well. Clean it. If that doesn't work, look up some of the threads on grinding your own ground glass.

[Keith Braithwaite]

Possibly a poorly, home made screen.

I just pulled the screen and had a look at it and I think this is right, it's a rough home-brew job. Still the whole camera only cost a couple of hundred bucks and is otherwise sound.

Thanks again, all.

Keith

[engl]

It is a poor GG, it is not diffusing enough. When sufficiently ground, the GG will scatter the light in all directions, what you are seeing is a lot of light going straight through the glass as if it were plain window glass. My previous camera from the 50s had a GG like that, you should see a big improvement with another GG (such as one from Steve Hopf) or by grinding your own with a good guide.