Condensor/Lens combo issue?

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BigSteveG

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Tried out my new my new (old) Durst-Pro last night. All works fine except for the fact I'm not getting enough exposure in the bottom left corner of the print. It doesn't appear as light fall off when projecting the image onto the easel. Moving the condensor a bit helps ever so slightly, but does not solve the issue. I'm using the condensor designed for an 80 mm lens w/ a 50mm lens. I wonder if this is the issue? Any clues out there?
 
Also, another side and (it feels silly anyway), question. My filter kit is missing the 2 1/2. I'm wondering if lay a 1/2 on top of a 2 will I get proper compensation?
 
BigSteveG said:
I'm using the condensor designed for an 80 mm lens w/ a 50mm lens. I wonder if this is the issue?
Click to expand...
In fact, this is the issue and the way out is to use the correct condenser for the lens or vice versa. With Dursts using a "bigger" condenser with a shorter lens doesn't work. Been there, done that.

Stefan
 
The condensers are sized for particular lens lengths- some of the Beseler 23C's at work tend to have the adjustable condenser units slip or 'ride down' in use, and start to vignette. It certainly is not always apparent on the baseboard.

As to your filtration question, alas no. I'd go with a 2 filter and increase develeopment a little bit- will get you to 2 1/4 at least.
 
Thanks for the expedient replies. Will using an 80mm lens for 35mm negs change things much? I suppose I'll have to raise the head and increase exposure to compensate? It's cheaper to buy a $40 lens than to look for the 50mm condensors I think.
 
The Nikkor 80 is excellent, and the Durst is likely bright enough to deal with the 5.6 f-stop. There are those who prefer to use longer lenses to print, theory being that you are using only the 'sweet spot' of the lens and thus getting more defined grain & detail in the corners. I never did any tests to confirm this, but printed 35 with a 135mm lens for years as that was the only one I had, and never wanted to go bigger than 1114 anyway.

With a condenser enlarger my guess would be that you'd notice less grain in the corners printing with the 80, as the light would be travelling straighter through the whole negative.
 
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I've got the older version of the 80, the metal barrel one, and love it. I believe the only difference is in coatings and barrel design (lighted f-stops)- and the coatings shouldn't matter much with b&w.
 
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