centering the image on the sheet of film

[Jordan]

Ok this is going to be a very easy question for someone to answer, but for some damn reason I am having trouble with it..... Ok here goes:

One of the main reasons I use a view camera is because I like straight lines and then at the same time being able to center the image...... I don't like to crop while printing and really enjoy making contact prints therefore no cropping..... ok here is the question:

The left side of my image has a hair less in it than the right side...... for example:
picture of house centered on ground glass, even distance on both sides from edge of a frame..... The negative has less space on the left side looking at the negative the "right" way. I am talking like an eighth of an inch, but that matters to some of my pictures. So my question is what direction should I shift the front to compensate for this? For some reason I can't figure it out even though I know I can. Thanks in advance. Hope everyone is well.

Jordan

[lenser]

In a nutshell, hold the negative up to the back of your camera and flip it upside down.....the way the lens actually projects the image. You'll be able to see that you need to slightly shift the back to the right to include more frame area.

It is just possible that your holders are not seating all the way into the camera back and therefore jutting out just a bit to the right, assuming that you load from the right.

Do you have the same left right problem when you shoot verticals? Is it possible that you are also losing some of the top of the image on vertical images? If you have different types of film holders, does this happen with some, but not others of a different make?

I have the same problem with my Calumet roll back being blocked by the film chamber and not going all the way in. I have to draw a pattern on the back to show the actual positioning rather than the ideal theoretical spot.

Good luck figuring this one out.

Tim

[Clay Turtle]

Right on the money with that reply, lenser I use the same technique for other things.
The image on the GG is upside down (vertical plane) & as well as in the horizontal plane, which as in photo shop, it is flipped.

[Jordan]

Thanks guys for your help so far. Now I have dtermined that is the right side of the image that has less in it...................the side that I slide the film in from. Still perplexed. My camera is horizontal only so I can't try the vertical experiment. Anymore logic into this is greatly appreciated.

[Jon Shiu]

Hi, it is just what you see in the ground glass is not exactly where the film is positioned (and/or is larger). So, you need to compose leaving a little more space on one side. Apparently this is common as I get one end of the image cut off with my Tachihara. John Sexton, former assistant to Ansel Adams, masks off his ground glass to account for the loss of image area near the edges.

Jon

[Leonard Evens]

By now I do it reflexively, but when I think it out, I realize I must be thinking subconsciously something like the following. If you just concentrate on what you see on the gg, it is clear that if you moved the back to the left, you would see more of what is on the right of the scene. One can explain that by the fact that rays emanating from points on the right end up on the gg on the left, but I think it is physically so obvious that few people would have trouble with it. But moving the back to the left is essentially equivalent to moving the front to the right., so that is what you should do: move the front to the right.

Similar remarks apply to rise/fall. Move the back in the direction opposite to which you want the image frame to move and move the front in the same direction.

Moving the front and the back in opposite directions are not quite the same because moving the front changes the point of view. That doesn't matter is normal photography because the change is small relative to the scene, but it can make a significant difference for close-ups. So for close-up photography, you are usually better off moving the back.

One remark on Clay's comment. The image on the gg,, when viewed normally from the rear of the gg, does not reverse left and right. It is rotated 180 degrees, so it preserves left-right distinctions. You can think of it this way. Imagine a sheet of transparency film in the camera. The emulsion will be facing the lens. Now imagine that the image is captured immediately in the film so you can continue to see it as you look at the film from the non-emulsion side. What would you do to get the image on the film to correspond to what you see in the film? You wouldn't flip it over; you would just turn it 180 degrees, continuing to look through the non-emulsion side. Another way to think of it is imagining altering your position so that the gg image appeared upright. You would flip yourself over to end up on your head, but then you would be facing the wrong way, so you would also have to turn around. If you were in a gravity free environment, you could accomplish the same thing more easily by rotating your whole body through 180 degrees about your head as you looked through the gg. Mathematically, we say that the combination of a flip through a horizontal axis followed by one through a vertical axis is equivalent to a rotation through 180 degrees.

Now, what happens to the image when it is recorded digitally and looked at in a photoeditor can be complicated, but in the end it is entirely arbitrary. It might reverse left and right in the image or it might not. You start with scanning the image, following the instructions for your scanner about how to place the film. Just what it does in terms of hardware and software in producing a digital image is arbitrary and easy to adjust to produce a desired end: if you follow instructions about which side of the film is "up", you should get an image preserving orientation when read by any image viewer, including that within the photoeditor. For example, the instructions for my scanner, an Epson 3200, say I should place it emulsion side up in order to preserve left-right orientation. For old darkroom enthusiasts like me that seems counter-intuitive because I am used to place the emulsion side down in an enlarger. I found it puzzling that Epson did it this way and wondered if there were some optical advantage to having the emulsion side up. I've never been able to find any mention of such an advantage and indeed some people argue that they get better results by placing the emulsion side down in such scanners. So why didn't Epson arrange so that it worked with the emulsion side down? I finally concluded that they did it so they could scan reflective sources and film in essentially the same way. I won't belabor the details, but, bascally because the light source is coming from different directions, that requires placing the film with the emulsion side up. This was confirmed in a sense when I got a Monolta film scanner which instructed me to place the film with emulsion side down, i.e., away from the light source.

[Alan Rabe]

You should also realize that there is a little bit of play in film holders. By that I mean that the film may not be seated in the same position in each holder. Some photographers will tap there holders on one edge to force the film to always be seated at a certain spot so all there negs will come out with the same edge borders