Vignetting with 50mm lens on 35mm film?

[Tom Stanworth]

All,

I have always used a 80mm to enlarge 35mm for convenience as I have a large enlarger (Durst 138) and can use the same lens for MF. however, in a bid to make bigger enlargements with less column extension I tried a couple of 50s and have severe vignetting at most but not all enlargement sizes. Is this caused by not using a recessed lens panel. It lookes like mechanical vignetting to me. I recall having the sme problem with a different lens on a Devere 504 but my memory might be failing me.

I have a Devere 108 and cannot even use a 80 due to bellows compression but have masses of extension so have used a 105mm for average enlargements of 35mm. But, seeing as I want to go bigger I have to start using the 50mm and would dearly like advice on:

a) the vignetting issue with the 138 durst
b) what sort of recessed panel might I need to use the 50mm on a devere 108 or am I stuffed?

Tks!!!

Tom

 

[David H. Bebbington]

Don't know if it helps, but IIRC a De Vere 108 lens panel is about 6 inches square, so there's plenty of scope for making a panel yourself - with even a deep recess, there would be plenty of room to reach in and set the lens stop. What head are you using? De Vere Varicon heads (interchangeable condensers) are notoriously difficult to set up for even illumination. It would seem unlikely that bellows that are big enough for a variety of formats would vignette with 35 mm, which is rather small in the middle of a large negative stage.

Regards,

David

 

[Jim Jones]

It might be a problem with the wrong condenser lenses for 50mm. Durst 138 users can advise on this.

 

[pentaxuser]

I have a Durst M605 and the 138 may not be the same but when I switch from 35mm(50mm lens) to MF(6X6) and the 80mm lens I need to change the panel. Both were supplied with the enlarger.

pentaxuser

 

[John Koehrer]

Sounds like you need a recessed board. Probably won't need different condenser since the larger condenser will cover the 35 neg. a proper cond. would more likely decrease exposure times