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fralexis
5-Mar-2012, 09:05
I have a monorail camera that easily corrects vertical convergences by tilting the rear standard. If I purchase a field camer without rear tilt, how do I make this correction? Thanks.

jp498
5-Mar-2012, 09:14
Make sure it's level. Then raise the front lensboard. A speed graphic can do it.

Brian Ellis
5-Mar-2012, 09:16
You keep the camera level and use front rise. If that isn't enough and you have to aim the camera up to include everything you want you're out of luck. Which is one of the main reasons not to purchase a camera without back tilt. However, almost all LF field cameras have back tilt, even the old ones. The only one I can think of offhand that doesn't (IIRC) is the Calumet Cadet though I'm sure there must be a few others.

ic-racer
5-Mar-2012, 13:09
Make sure it's level. Then raise the front lensboard. A speed graphic can do it.

More specifically, make sure the back is plumb.

Heroique
5-Mar-2012, 13:39
If your field camera has rear swing, you can rotate it 90 degrees, and presto, you’ll have rear tilt.

Leonard Evens
5-Mar-2012, 13:44
Verticals in the scene will be parallel and vertical in the image if the camera is back is plumb, i.e., vertical. The crucial requirement is that the back be parallel to the lines in the scene that you want to be parallel in the image.

You only need to raise the front or lower the back if the top of the building is not within the image. But with limited rise/fall allowable for your camera, you may still not be able to get the top of the building in the image when the camera is level. In that case, you can point the camera upward and tilt the back, if that is possible, so that it becomes again parallel to the desired verticals. If you do this you should also tilt the front so it is also parallel or else you will shift the plane of exact focus.

One way to think about this is to try to visualize the front and back standards as though they were freely movable in space. The supports are necessary to prevent gravity from leading to a collapse of camera components, but they play no role in the optics. Whatever you do, you need the back plumb if you want verticals in the scene to remain vertical in the image and you need the front and back standards parallel to one another to avoid shifting the plane of exact focus.

Leigh
5-Mar-2012, 21:21
All field cameras I've seen have rear tilt.

Since that's the mechanism used to close the body for transport and open it for use,
inclusion of the function is free and trivially simple.

In normal situations the rear is not used in other than the 90-degree position.

However, if you can't get enough rise from the front standard alone, it's possible to tilt the camera bed, then reset
the front and rear tilts to bring the back vertical and the front parallel with the back (or other angle as needed).

- Leigh