enlarger vignetting / light fall-off

[polyglot]

Hi all,

I'm using an LPL 7700 with condenser head and Rodagon 105/5.6 (old Zebra version) to print 6x7. I made a bunch of 8x10s last night and am finding that the prints are distinctly paler in the corners. I was running the lens at f/11 to f/16 so didn't expect vignetting at all, particularly at this low magnification (lots of bellows extension).

Is this a known issue with this lens or is it perhaps an issue with evenness of negative illumination from the head? I can burn the corners down a bit, but would prefer to get a uniform print straight off if possible.

Any suggestions/reasoning appreciated...

 

[Erik L]

I'm not familiar with the lpl 7700 but do you have the condensers in the correct position?
erik

 

[polyglot]

uh, maybe? How do I tell what the correct position is?

 

[John Koehrer]

Some enlargers have a diagram inside the filter drawer access plate.

 

[polyglot]

thanks; I'll have to have a look.

 

[polyglot]

That was exactly it. Found instructions on the inside of the front door - have to remove the top condenser element and push the bulb closer to it. Light nice and uniform now.