bellows extension esposure compensation

[z_photo]

It will be a while before i see the results. I have shot a few sheets to see if i have figured out my issue, but here is a question.

i seem to have done a good job calculating the bellows extension compensation for a 300mm lens. but when i shot the nikkor 360 tele i goofed. of course it is possible that i miscalculated for reciprocity failure but i got that right with the 300.

so should i calculate the bellows extension compensation based upon the measured extension beyond the infinity focus extension rather than based upon the lens focal length?

thanks in advance
kyle

[BradS]

so should i calculate the bellows extension compensation based upon the measured extension beyond the infinity focus extension rather than based upon the lens focal length?

thanks in advance
kyle

Yes.....especially critical with a telephoto design.

[z_photo]

Yes.....especially critical with a telephoto design.

thanks, Brad. i think that explains (at least partially) why the exposure looked to be a stop or a bit more over. in retrospect i should have made that connection when shooting. the 360 extension was less than that for the 300. i was just happy that i came home with a lot of satisfying results from my first 4x5 shooting.