This may be a particularly problematic camera (as are some other Graphics), with an additional consideration. There is the additional variable of thickness of the fresnel.Originally Posted by Brian C. Miller
This may be a particularly problematic camera (as are some other Graphics), with an additional consideration. There is the additional variable of thickness of the fresnel.
If the ground surface of the original ground glass and the ground surface of the new gg are resting on the same shims then there is no focus shift. If you reset the positioned the position of the shims then you have shifted focus. If you had a Frenel screen under the gg and you replaced it with a thicker fresnel or a thinner one then you may have shifted focus.
If all you did was remove the gg hold down clips, removed the original gg and placed the new gg in the same position and replaced the clips then you did not shift the focus.
What did you do when you did the replacement?
[dupe
Thanks Bob Solomon! I simply replaced the Chamonix GG with the Steve Hopf "boro" glass - no shims were involved. OK, now back to shooting!
In the situation with the Super Graphic (referenced above) it could/would change the focus, if the original focusing panel was an Ektalite with the fresnel sandwiched in front of the ground glass (i.e. toward the lens)-- and the new replacement GG was simply a piece of ground glass mounted in the same plane. (Very common error).
Sorry it is not thad easy, because at a longer lens you get more deep of focus behind the lens then with a 47 XL it is very criticaly even at f16 or f22!At f16 your focus spread is about a millimeter, so that will cover a condition of combined intolerance of plus-or-minus 0.5 millimeters. That should be good even for home made cameras and film holders
I really know it from the past!
Cheers Armin
Yes, Ivan, you are right about the GG. When I bought the camera it had a replacement GG, which had no fresnel, and the focus was quite definitely off. Then I replaced it with a fresnel GG, and checked focus again. The focus was better, but it still needed adjustment. I spent lots of Polaroid shots on a ruler, and time measuring and shimming the GG. Now the focus is spot-on!
Polaroid's film plane is not the best thing to rely on unless you will only shoot Polaroids. And that is becoming ever more doubtful today.Yes, Ivan, you are right about the GG. When I bought the camera it had a replacement GG, which had no fresnel, and the focus was quite definitely off. Then I replaced it with a fresnel GG, and checked focus again. The focus was better, but it still needed adjustment. I spent lots of Polaroid shots on a ruler, and time measuring and shimming the GG. Now the focus is spot-on!
Had you replaced with a gen-u-ine Ektalite it would have worked as a drop-in, no matter which GG was used. The OEM Ektalite, however, is getting VERY hard to find... hence the need for measuring, shimming, etc.
At least that was my experience and the wisdom imparted by WD Service, Inc., which was the Western Division Graflex repair depot.
Hi Bob! If you read the original thread, you'll see all of the measuring I did between all of my film holders. Both Fidelity and Polaroid holders have the same depth, and Graflex is 0.005in shallower. Now, I would agree with you that it would be an issue if I had been using the 550 pack holder instead of the 545, which is what I used during most of the calibration.
The final shots were made using Fidelity holders and Techpan. Yeah, it is something special to see bicycle spokes at two blocks away!
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