Problem with a new 50mm lens (Meopta Opemus 6a enlarger)

S

shOo

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I have been printing with 80mm lens, but decided to buy a new 50mm lens for 35mm film. Yesterday I wanted to give it a try, but it didn't work. The lens (Rodenstock 50mm f2.8 Rogonar) mounts fine, but I can't focus with it. I mean I haven't got enough movements with the focusing knob to make it sharp, unless I am printing at almost contact size.

What could be the problem? The lens almost goes inside the enlarger when trying to focus, but it's not enough. I hope you understand what I mean.

Thanks.
 
agreed - if you're cranking the bellows all way up and still not QUITE getting there, this is the likely culprit. my newish-to-me LPL uses reversible lens boards, so you basically flip them between 35mm and MF lenses, recessed mounting being for 35mm (or smaller I suppose)


sevo said:
Many medium format enlargers need a recessed lens board to be able to use 50mm lenses.
Click to expand...
 
Near to where the lens mounts around the lip as it were is a little thumb screw, unscrew the lens first and set aside, then unscrew this little thumb screw this will drop the lens and the lens board out, you need to turn it the other way over and then put the lens board back in place the other way around, screw back in, then put the 50mm on.

Then you can focus.

This is the case with my Opemus 6 (the 6a is virtually identical)

I can't remember if the lens board needs to be concave or convex for 50mm or 80mm, I think (and I'll probably get the wrong) it needs to be convex for 75/80mm and concave for 50mm...

Vicky
 
exactly like the LPL, and makes sense logically for the different focal lengths. concave (lens closer to negative) for 50mm lens, convex (lens further from negative) for longer.


Lilserenity said:
Near to where the lens mounts around the lip as it were is a little thumb screw, unscrew the lens first and set aside, then unscrew this little thumb screw this will drop the lens and the lens board out, you need to turn it the other way over and then put the lens board back in place the other way around, screw back in, then put the 50mm on.

Then you can focus.

This is the case with my Opemus 6 (the 6a is virtually identical)

I can't remember if the lens board needs to be concave or convex for 50mm or 80mm, I think (and I'll probably get the wrong) it needs to be convex for 75/80mm and concave for 50mm...

Vicky
Click to expand...
 
As said, you need a recessed lens board. Chances are, you already have, but it's currently mounted `recessed-side out'. Use the aforementioned thumbscrew to remove the lens board, reverse it and replace.

If you have a normal `flat' lens board, FotoImpex in Germany sells the board you want.

I recently had the same problem with my Opemus III.
 
Thank you very much for quick and useful replies! So it seems like there is some hope in using the lens without buying anything more. I will try that, and let you know
 
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