Image alignment problem on Toyo 45cgreenspun.com : LUSENET : Large format photography : One Thread
Hopefully, someone out there might give me a hint as to what is happening with my Toyo 45c. Recently two situations presented themselves when photographing two interiors for clients.
The first, was detail shot of mosaic tile work in a bathroom, the top and both sides were perfectly square and parallel to the edge of the frame. However at the very bottom, say the last half an inch or so, the last row of tiles(which should also have been square and parallel) skewed off the bottom, left side of the frame(the right side was relatively in the right place).
The second, was an odd situation. The client wanted an exagerated view of a very tall home with a perspective from the floor about ten feet in front of the camera to the ceiling that was almost directly overhead. Tilting the camera, gave only two spots which to level the camera which steps on either side of a ten foot waterfall at the bottom of the frame. As distorted as everything was in the frame it did not become noticable until the film returned from the lab, that the peak of the ceiling was tilted to the right of the center of the frame by a couple of degrees(or about identical to the tilt of the tile in the bathroom.)
I had attempted to align the standards on the camera after the tile incident, obviously to no avail. It can not be the lens, the tiles were shot with a 90mm f/6.8 Rodenstock and the home/waterfall was shot with a 65mm f/8(?) Schneider and different lens boards. The tripod was leveled and at least with the tiles shot the camera spirit level was level. I can't remember if I checked for level at the home/waterfall shot(probably not.)
What doesn't click in my mind is that (specifically in the tile shot) how could all three sides square and parallel and the fourth be so far off. If the camera was out of square, wouldn't two of the sides have to be out of alignment at the same time?
If someone has an idea or needs more information I did not provide, please contact me. I am having to shovel out several hundred dollars to digitally fix the home/waterfall shot(of course the client just had to pick that one.) The problem is most apparent with the tiles shot and I could be emailed if that would help clarify the problem. Thank you.
Tom Percival firstname.lastname@example.org
-- Tom Percival (email@example.com), November 09, 2000
Most of these sorts of problems actually turn out to have really silly solutions.
My guess, and it's only a guess, is that it has something to do with the filmholder. Could be that the film is getting caught and turned up at one corner.
Was the same filmholder responsible for both anomalies?.
Try setting the camera up with similar movements, load the camera normally, pull the septum, then take off the lens panel and see what the film looks like. Give it a prod with a pencil to see if it's lying flat. OK, you've wasted a sheet of film, but at least that'll be one thing eliminated. If the DDS isn't being loaded properly, the film might be slipping partly out.
-- Pete Andrews (firstname.lastname@example.org), November 10, 2000.
Tom: If the two sides, and top were square, then the image area must not be rectangular (simple geometry!). Measure the two diagonals of the image... if they are not equal, then this is confirmation that your image area is not rectangular. As Pete suggested, this is probably due to the opening in the film holder, not the opening in rear standard of the camera.
-- Glenn Kroeger (email@example.com), November 10, 2000.
Tom, I have no idea about the toyo onstuction , I've used a 45G but it was long ago, I have a Wista VX and this camera, as several metal fields, offer a mechanism which allows for the shutter to be automatically closed when the film holder is inserted in place. This actually has a spring loaded lever which pushes a cable between camera and shutter(some shutters are especially constructed to operate this way) therefore closing the lens. This can put your film holder under a certain strain ,on one side more than the other three,(I agree that at least one of the remaining ones shold show some sign of warping too), however I never experienced what you said, the only problem occours to my polaroid holder which in certain positions is pushed a little out of its exact place. Another thing might be produced by incorrect insertion of the film holder ; with this last one actually catching some protrusion and there fore having a slight tilted position,mind you, this would have to be very small in order not to produce any freak parassite light effects on your film. Toyo has its own production of film holders and they just might be slightly more suited to your camera than the rest of more common brands. Does this happen with all film holders or only with certain ones? As it has been suggested the might be warped. By the way a perspective change in photoshop is a relatively easy task(when scanning you also invariably do some other corrections as well.... dust retouching being one of the most common ones) and shouldn't cost so much money, a skilled operator has to be able to fix this in more or less one hour(scan time included), go sit next to him or her and check that the time is the time that it really took them. $200 shold by you plenty of computer time and skill! Keep me informed on further developments. Regards
-- andrea milano (firstname.lastname@example.org), November 11, 2000.
Tom: If you have ever laid tile or have been involved in construction you know that things are not as they look and that perfectly squared alignement is the exception not the rule. It all depends how carefully you look or measure. If you can go back to the customer you could measure the diagonals to the nearest mm. and if they are equal, the job is square and the problem is yours. You may be surprised. Tilers know the what is most important is for the job to look square, not to be square. A perfectly square tile job might reveal that one of the side walls is slightly off and that it requires the tiles to be laid in such a fashion as to match the wall. The tiler knows that no one will notice slight differences in the grout's width, and that the slight differences are cummulative and enough to bring the tiles in adequate alighment with the wall.
What follows may not relate as well to some of your problems and if relates to them OK. To get the subject's lines horizontal on film, not only the camera frame must be horizontal but the film plane's horizontal axis must also be exactly parallel to the subject's horizontal lines. Positioning the camera on a horizontal position is probably the easier thing; getting the film plane's horizontal axis parallel to the subject's is more difficult and requires very careful viewing with a loupe. Because the 4X5 image size represents a major reduction from the original and additionally, the ground glass reduces the subject's edges sharpness, a loupe is a must.
Finally, levels are not always perfect. Liquids will seek a horizontal but that does not guarantee that the level's markings, or the placement of the glass within the frame, or that the level's frame are all as accurate as needed. To calibrate your levels you will need a precision machinist's level. You need not use one for picture taking but only for calibrating your camera and tripod. If you can borrow a precision machinist's level (they can be expensive, near $200), use it to calibrate yours. Precision levels are finicky things and the slightest deviation from the horizontal, which would not wake up an ordinary level, will send the precision level's bubble on a trip all the way off. These things are usually not much longer than the frame of a 4X5 so you should have no problem placing one on top of the Toyo. Best luck.
-- Julio Fernandez (email@example.com), November 11, 2000.