Hi, all -
I'm toying with the idea of an extension back on a WP camera to bump it up to 8x10. I've read a bit about them, but never seen one, so I'm not sure how to go about designing/building one.
Anyone have any suggestions or pictures they'd want to share? I'd be eternally grateful.
Thanks,
Scott
Hi Scott,
Here is one, I'm not sure what a "WP" camera is but this is an extension back. They are made wood, metal or whatever material you are able to work with. One side is the format size of the camera and the other side is the format size of the back. Pretty basic and not hard to make. If you have an 8x10 back then it's only a little woodworking. This one looks like it has about four inches of additional extension. Good luck.
Another coincidence of stars in alignment - check your mail, Scott.
Thanks, Turner. Just what I needed to see. BTW, "WP" was short for "whole plate".
Hmm, compound mitered sides would be nice...
Well, anyway, for one and all ...
Extension back from 4x5 to 5x7 made of basswood strips and sheet. I made a cardboard dummy first off to check the necessary depth and angles.
Was this done for a 5X7 camera? How much distortion, if any, do you get with the extension?Originally Posted by Turner Reich
Beautiful work by you and the other that posted the photo...
Distortion? Why would you get any distortion. I don't think this is even a consideration. You get no distortion, unless the rear ground glass is not parallel with the lens. This would be a function of the camera movements not being set at zero.
Somewhere I read that the Tachihara back made specifically for the 4X5 gives distortion, but it's rather this as a user's experience:
Minus: The big drawback is that the internal geometry of the camera remains 4x5, thus there is a lot of limitations on the movements and long lenses that can be used. The limitations listed are not too bad for wide angle landscape photography.
When using short lenses (eg 120), the lens has to be in the camera. Therefore, there is no possibility of shifts, plus you have to use an awkward front standard configuration, plus the tilts are limited to the back. Lenses shorter than 120mm can't be focused at infinity due to the box+body+bellows+front standard not compressing to the flange focal length.
When using longer lenses, ther problem is that since the extension is a cone joining the 5x7 back to a 5x5 square, to avoid vignetting by the internal elements of the camera, the lens has to lie inside the cone. This is not a problem for the large border , but definitely one for the small one. It means: no extension longer than 260mm. In particular you cannot even use a normal 300m with the 5x7 back (but a 360 telephoto works). A 300mm on the 5x7 is the equivalent of a 60mm for a 35mm camera, thus this is pretty short.
With tilts, you have to be quite careful to avoid vignetting. I have found that with the 120mm (horizontal and moderate vertical) it is OK, but with the 210mm I cannot get enough vertical tilt in vertical format. Shifts are also extremely problematic.
I don't think distortion is the right word to describe the limitations. There are limitations such as those described ... but, you work within those if you don't have a larger camera.
Another cracking Sandeha Lynch creation - nice work!
Aynsley
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