Omega Pro-Lab condenser

[Thomas Bertilsson]

I have a question on something I can't figure out. Recently I bought an Omega 4x5 Pro-Lab enlarger. When enlarging 4x5 negs I'm doing fine, I get nice coverage with the top condenser removed and the 150mm lens.
Then I try printing Medium format negs, and all I get is a small round circle on the easel. The top condenser compartment has a guide that clearly illustrates how that supplemental condenser element should be installed for using the 90mm lens (and 50mm for 35mm negs). What's worse is I can't even focus it.

The question is:

1. Since I'm not using the #212 light bulb (it's in the mail but didn't get here yet) but rather a standard 100W light bulb with the stamp scratched off, is the light source too far from the condenser lens?
2. Is there a chance that the top condenser might be the wrong one?
3. Is there a chance that the bottom condenser lens might be wrong?

If there's anything else you can think of, please share.

Thankful for help,

- Thomas

 

[lee]

I think the lens board needs to be a flat one and the 150mm lens board is a 5 inch cone. I think that is the problem.

your questions:
1.probably not
2.I doubt it
3.I don't see how it could.

lee\c

 

[Andy Tymon]

Thomas,
I too have a prolab, have you tried adjusting the bellows length with the lever thats located below the lens stage? I'm assuming you have all 3 condensors, two in the silver cylinder above the neg carrier and the adjustable one?

 

[Paul Howell]

I have a D3, for 6X6 top condenser in bottom slot with a 80-90mm lens, for
6X7 or 6X9 90-105mm in middle slot, for 4X5 135 in top slot or 150-160 with top condenser removed.

 

[Thomas Bertilsson]

Lee, so the enlarging lens is too far from the condenser lens?

Andy, I can't picture in my mind what you're referring to. I'll have to check tonight when I get home. Something's screwy with the setup.
I have all three condensers, for sure. Two with the convex sides facing each other in the bottom cylinder, and a third with the convex side facing down in the top compartment, with three slots to put it in.

I'm starting to think that Lee is right. Either a flat lens board, or maybe it would suffice to compress the bellows all the way...?

Thanks for all your input. I have something to work with now.

- Thomas

 

[Donald Miller]

Lee is correct. The 150 lens is used with the cone and the shorter lenses with a flat lens board.

 

[lee]

I have had several Omegas and all the D series (4x5) enlargers work that way.

I found this by googling Omega D 2 and it is a Q and A forum at Classic Enlargers.

Harry said this, " Harrry Taylor
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Re: DII lens cones or lens boards for smaller lens
« Reply #1 on: Apr 25th, 2004, 10:15pm » Quote Quote Modify Modify
For all lenses between 50 and 105mm use a flat lens board.

The cones are used only for the lens used for 4x5 like 2 3/4" Cone for 135mm and 4 1/2" Cone for 150mm.

At one time 161mm (same a 5 3/8") was used for 4x5 negs and according to the D-II manual it should work OK on a 4 1/2" cone, like the 150mm.

Most people now use 135mm. But if you have it and it is clear and the diaphragm works OK, give it a try. Might be a keeper."

lee\c

 

[Thomas Bertilsson]

Thank you Donald for confirming that. I guess I can start looking for a flat lens board now...

Thank you,

- Thomas

 

[Jon Shiu]

Hi, just fyi the pro lab uses an adjustable bellows instead of cones. So, like a previous poster suggested, just use the little lever to collapse the bellows to flat.

Jon

oh, forgot that the usual lens plate is about 1/2 inch extension and also flat board is possible, but may be hard to slide the lens in.

 

[Thomas Bertilsson]

And thanks again Lee for finding that. I appreciate it. Harry Taylor is a recognized authority on these old Omega enlargers. I've spoken to him before.

- Thomas