I will photograph something flat and see how that looks.
I will photograph something flat and see how that looks.
Here are some photos of the setup.
This question is complicated by the fact that Toyo produced two almost identical ground glass frames with different registration distances for the ground glass. If that is not enough, the Fresnel lens may be clipped onto the ground glass in both frames, but will need spacers that were once available in a kit for the sandwich to focus correctly in one of the frame designs, but needed no such spacer in the other design. I found this out the hard way. And dealers/owners switch them. I am sure you have enough to worry about, but I thought I would share my experience anyways. The ground glass frame of the 45C did not come equipped with a Fresnel, the special kit of Fresnel plus spacers was 180-803.
I know it's been a little frustrating, all the D45M models I see online have the same exact setup as mine. I took a photo with just the ground glass and will develop it tomorrow and see if that makes a difference. It actually is easier to focus without the fresnel installed and not noticably any dimmer.
Originally Posted by photojpg
You are way ahead of the game since you have detected the problem in the first post. Don't group yourself with the less astute.
Even in the old days when one could sent a LF camera for repair, it would unlikely come back so it focuses the way you want with your film and film holders. No one except you know how you position the image plane when you focus, or how your film holders hold the film.
Obviously, unless the film holder is damaged or improperly made, the T-distance can never be greater, but it can easily be less if the film is bulging or is not pressed against the back of the holder. This condition of improper film placement, of course, places the focal point farther back in the scene, than expected.
photojpg,
You have correctly diagnosed your problem: a misalignment of ground glass/Fresnel screen. Don't get hung up on your preconceived notion that everything is exactly as it should be; it's not.
As others have said, if the focus on the film is more distant than the focus on the ground glass, then the film is closer to the lens than the ground glass (or, maybe more helpful, the ground glass is farther back from the lens than the film). This would mean that you would have to find a way to set the ground glass further into the camera back, not an easy task on a metal camera unless you're a machinist. If that is the case, then likely the Fresnel screen is simply not supposed to be where it is. Your experiment with ground glass alone should tell the tale.
If the focus on the film is closer than that on the ground glass, you have the opposite problem: the ground glass is too close to the film. This is much easier to deal with by simply making shims and installing them till you get the right spacing (you can often estimate closely how much shimming you need by returning to the test subject with your notes and the test negative in hand and then focusing on both places and noting the difference).
A good test is to photograph a ruler at an oblique angle to the camera, focusing on a middle value (e.g., the six-inch mark) and then shooting wide open. Develop the neg and see where the focus really is and adjust accordingly. To control, shoot a wide-open shot of a distant jagged horizon line, and see if it is in sharp focus.
FWIW, I do this with my cameras fairly regularly when I'm printing. I'll take the camera outside, photograph the horizon, walk into the darkroom and develop the neg in the print developer for three minutes or so. Stop, fix for a few seconds and inspect the wet neg with a loupe. If all is well, the neg goes into the trash and I resume printing.
Best,
Doremus
Thank you to everyone for your suggestions and help. I removed the fresnel lens which does not effect the distance of the GG and exposed some photos last night. I photographed some flat objects close and others I out behind it at different intervals. I just developed those negs (my first try at tray developing with pmk) and so far they are very very sharp where I focused and the distant objects are blurry like they should be. I can only assume that the fresnel lens was causing it to focus incorrectly, the image is easier to focus without it. There must have been something wrong with the fresnel. I have ordered a fresnel GG combo screen and will see if that works as well, hopefully it is brighter and focuses correctly. If not I will just use my GG I have now. I still have to take some regular outdoor photos and see how they come out. It is raining here now so hopefully tomorrow, thanks again!
A Fresnel screen between ground glass and lens will refract, i.e., change the apparent focusing distance, one third of its thickness. If you're getting good focus without the Fresnel in place, then it likely shouldn't have gone in that position, or the whole sandwich needed to be displaced by the proper amount. Would shims help?
Doremus
Although I don't remember the details, I do recall that Toyo used a non-standard setup regarding the orientation of its fresnel lenses and ground-glass.
As such, I suspect your fresnel lens is fine in and of itself, but simply wasn't installed correctly.
I got instructions from Toyo on the correct order and which way the shiny side faces, it faces the lens which is not Ike other fresnels, its a mystery as to why it works better now. I'm positive it was installed correctly since I followed the directions from Toyo and that is the same may it can when I bought it. I cleaned it the proper way and installed it the way Toyo says in the directions. My camera is very old it was made in 69 or 70, it's the tan one.
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