That Technika III Ground glass thing again help.

[cyberjunkie]

My Technika III (5th version, with graflok back and tapered cover/base) came with two ground glasses:
- the original one, with grid (unfortunately broken in two pieces!)
- a replacement one with no grid, of the same thickness, but possibly with a finer "grain" (a little more luminous though with less differentiation between in/out of focus)
NO fresnel, either separate or in one piece with the GG (as in my Pacemaker Speed Graphic).
No traces or any other evidence that it ever had a fresnel before... and the same holds true for the Technikas used by some friends.

I think that the ground glass you got is thinner than the original one.
It is NOT a big problem, as the ground side, where the image is formed, sits on the same plane of the old glass.
The best answer was already given: shim the GG where it is held by the clips.
You just need some cardboard to firmly seat the GG in place.

If you want to go the fresnel route, you don't have to spend much money.
With a 4x5" camera and a 150mm lens, there are good chances that a cheap fresnel (one of those flat reading lenses), cut to size, would work more than OK.
Of course it must be fitted behind the GG.
If you have a small saw at home, it would be almost as easy as cutting cardboard shims, and cheap enough to ditch the fresnel if you find that you don't like how it works.

have fun

CJ

[Michael_4514]

No fresnel on my Tech III either.

[Don_Ashcraft]

My tech III came used (very) with what I believed to be the original fresnel. I removed it when I replaced the broken ground glass and shimmed it as posted earlier. I have always thought the fresnel was added but was told it was added early on possibly as an option. I really had no clue, so I have read this thread with much interest, thanks!

I still have the fresnel. It is dull and blocked a lot of focusing light, so it's not missed much. Personal preference, I guess.

[coisasdavida]

On my Tech III v5 I see two places where a GG could rest. In fact, if mine was a bit shorter on the long side it could rest lower into the frame (closer to the lens), then the springs wouldn't reach it for sure.

With a metal ruler I measured aprox. 4,5mm from the face of a film holder to the film plane. Between the two places I could rest the GG on the frame, I believe that I have it on the right spot. The other option the frame would be around 3mm deep (closer to lens).

I just pulled the GG out to take a look (got it washed with soap too, after all it kind of needed that). When trying to install it back, I noticed that you have to be careful enough, not to let it drop to the wrong surface on one side when fastening the first screw on the spring on the other side. This could have happened to yours.

That bottom rail on the frame could be for a fresnel, but based on my measurements, I believe GG and fresnel should sit on different machined surfaces.