Another swirly lens question....

[John Kasaian]

Anyone use as 7" f/3.5 B&L projection lens on a 4x5 or 5x7?
Your thoughts & opinions?

[Richard Rankin]

A 7" B&L probably has an internal ring inside to make it slower, so you might check the f3.5. But a 7" petzval should have a max image circle of ~ 7" as well. The diameter of a 5x7 piece of film is approx 8.6", so your petzval is not going to cover at infinity. Even close-up, I'd think you'll have some vignetting on the corners. 4x5 has a 6.4" approx diameter, so it might work ok on that.

Richard

[parleton]

it should cover 4x5 fine although due to larger image circle you might not see the swirling on 4x5. i just shot an 8 inches petzval cinema len on 4x5 on wet plate. don't forget taking into account of light falloff due to bellow extension if you want to do close up portrait.