[LargeFormat] 9/450mm on lensboard issue

[Clive Warren]

At 9:36 am +0200 3/9/01, Frantisek Vlcek wrote:
>I need some feedback please about mounting a 9/450 barreled apo-tessar
>on (hopefully, if I bid well) 2 1/4 x 3 1/4 Graphic...
>
>Is the following reasoning right, please?
>
>I just imagined the light cone coming from the lens to film, and I
>fear that my idea of mounting it on the small graphic is impossible,
>at least with 2.25x3.25 back. Why? The nodal point of the lens is
>450mm beyond film plane at infinity focus. The cone of light quickly
>widens. So to deliver a 2.25x3.25" dimension image at filmplane, it
>mustn't be cut off earlier - I guess a lensboard holle would have to
>have minimum dimensions 2x3" to pass enough of the cone to form a
>2.25x3.25" image at film plane. And if the already small 23 Graphic
>lensboard had this kind of hole in it, would it still be structurally
>stable enough? Maybe it's even smaller? Anybody has the dimensions of
>a 23 Graphic lensboard please?
>
>Thank you
>       Frantisek
snip

Hope you won your 2x3 Graphic.

The lens board size for the later 2x3 Crown and Speed Graphics is 
approximately 2.5" square. You can easily test for vignetting 
problems using a cardboard tube and some tape to temporarily mount 
the lens on the camera.

Good luck.

Cheers,
        Clive