recessed lensboard

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hi, as far as i know , the recessed lensboard helps to buy extra bellow length for movementsesp. in wideangles. But besides the higher cost, will it cause any harm if i used it instead of normal lensboard ,says in "normal lens--90-120mm" in a rail view camera , e.g. jeopardise the front standard movement ? thanks

-- benz (wchiping@hotmail.com), February 20, 2002

Answers

Your right, about the lens board with a wide angle... it won't do any "damage" and your 90mm-120mm is still a wide angle area... If you were to say use it with a 210, you would be using more bellows draw than you need and giving yourself more headaches if you don't factor bellows factor. Cheers

-- Scott Walton (walton@ll.mit.edu), February 20, 2002.

Don't forget that it does move the axis point of the lens to a point behind the axis point of the front standard, meaning any on-axis titls will not be on-axis. The difference should be pretty negligible, though.

-- Todd Caudle (todd@skylinepress.com), February 20, 2002.

Actually, the fact that a lens is on a recessed board does not change the bellows extension since the extension is related to the lenses focal legnth and not bellows draw. If I have a 210mm lens on a 1" recessed board the bellows draw ( that is lens to film distance ) is stil nominally 210mm, not 210mm + 1". So no bellows extension factor need be applied. I have also noted that most front axis tilt points on cameras are actually behind the center of the lens so using a recessed board may actually improve the tilt action.

-- Jeffrey Scott (jscott@datavoice.net), February 20, 2002.

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