Sinar F2 dof calculator problem

[Jan Virtanen]

For some reason i do not get enough DOF when i use the calculator for the optimum aperture.
Background seems to be out of focus. I wonder if theres something wrong with my way of
using the calculator. I focus on far, reset calculator, focus near, and read the suggested aperture,
then i refocus it one f stop down on the scale. I am puzzled.

[David E. Rose]

The refocus point is supposed to be two stops down. Also, make sure that you focus wide open.

[Jan Virtanen]

Focusing wide open yes, i tried two stops down to refocus but stil the bg seems to be slightly out of focus.

[Jan Virtanen]

I think the forground seems to be out too, maybe my camera is out of alignment or something?

[Jerry Flynn]

Jan,

Your comment about alignment may be correct, but you did not describe your shooting conditions. I may be wrong, but I believe the DOF calculator is optimized for infinity focus. If you are shooting very close up, there may be an inaccuracy.

Also, just to reitierate, if the calculator indicates f/22, you rack the focus back to the f/11 mark on the dial.

[Jan Virtanen]

Yes i tried to back two stops, but its still slightly out of focus. I noticed that the front standard
is slightly tilted backwards.
I rudimently measured it with a vernier caliper and it seemed to be about 1-2mm out of alightment,
I wonder how it can be fixed, sending it to sinar will propably cost a great deal

[Ellis Vener]

Also try using the 6x9cm format scale instead of the 4x5 scale.

[Jan Virtanen]

Btw, this is the special 5x7" model.