Speed Graphics, back frame bent?? One-side sharpness :(

[eumenius]

Hello friends,
today I tried to see how my old Tessar 135/4.5 works for night shots, compared with Ektar 127/4.5. The whole picture is quite similar, and the contrast is quite the same at f/8 and 1 min exposure, so loud cheers to 1924 uncoated Zeiss - but... I focused with a 4X loupe on a very very far building to see how should everything look like, and I got some strange problems with overall sharpness. The far building I focused on is very sharp, the other stuff on this side of the neg is sharp too, but every other thing on the another side of the same negative is out of focus, even the buildings on the same distance as the sharp ones Well, I left the camera at my lab, so I don't have an option to check everything now, but I have two things in mind. Maybe the camera back with decades passed got somehow misaligned with the front standart? If it's possible, how can it be adjusted? Or maybe I am idiot by myself, because I didn't fix the infinity stops on the rails even (with ruler, as I usually do), and the lens (without stops at all, just pulled and stopped somewhere apparently aligned) was "swinged" for too much? The front standart carriage has some side play, of course That's my lack of experience with LF, no doubt. So, before I checked all-over the field sharpness with loupe tomorrow, what can be your diagnosis, o experienced guys?

Feeling crappy,
Zhenya

 

[Dan Fromm]

Zhenya, it is very easy to get a little unintended swing with a Graphic if the front standard is not pulled up firmly against the infinity stops.

Since I shoot more focal lengths with mine than it is practical or affordable to set up infinity stops for, I use a "moveable infinity stop." Basically a top-hat shaped bar that lies upside down across the rails. The narrower section fits snugly between the rails. And there is a cut-out machined in the middle of the narrower section to clear the front standard's latch. This is the latch that allows shift with Pacemaker Graphics, I don't think your Anny has one.

Before I got my moveable stops, one from Fred Lusting, who calls it a chinaman, the other from SKGrimes, I used a small T-square to align the front standard ...

Good luck, have fun, don't feel crappy, be happy,

Dan

Oh, yeah. Why do I have two moveable stops? Because my 2x3 Pacemaker Speed's rails are a little wider than my Century's rails. One size doesn't fit both.

 

[noseoil]

Zhenya, welcome to the wonderful world of large format! It sounds like you may have had a small alignment problem, but it might take just a little time to sort out. Start with the basics, always. First, I would set up the camera on a good solid tripod. Next compose and focus on a similar shot, with about the same distance as the other shot. Use a loupe to check focus for every part of the ground glass you can see clearly. If you notice the same softness in the same area, try some small movements to correct the image. Once you have found the problem, set your stops to compensate for whatever it is and try a shot.

One of the problems with movements is to get everything perfectly aligned at "0" so you know where you are in the shot. I have set up slightly wrong on shots and did not notice until the film was developed. Usually, it was due to my carelessness when I first set up the camera. I blame myself, not the camera in most of these cases, except where the camera is clearly to blame for a bad shot. tim