Disassembling an Enlarger Lens . . .

[John Galt]

I have a Schneider Kreuznach Componon 105mm enlarging lens I picked up for $5 . . . It is very clean considering its age except for one tiny spot on one of the internal lenses . . . looks like a spot of fungus. I would like to disassemble this lens and see if I can clean it up. Can you folks point me toward a guide / tutorial on disassembly and cleaning of such a lens? Are special tools needed?

Thanks

 

[jjphoto]

I think the front half of the lens just srews off with the front group .try it. Dissembling groups needs tools.

 

[mshchem]

Best of luck, if it's between 2 elements cemented together it's hopeless, I would clean as far apart as you feel comfortable and try it. If it's not bad you probably won't notice. If it's on the perifery of the glass and not in the center at f 8 you won't see a thing. For 5 bucks it makes for an elegant paperweight

 

[E. von Hoegh]

With a good spanner and some care it should be possible. I'm not familiar with this lens unfortunately but enlarging lenses are pretty simple. Try umscrewing by hand the front and rear cells for starters.

 

[Patrick Robert James]

I believe the old Componons (not the Componon-s) were put in shutter sized barrels so you should be able to just screw out the front and rear groups. Odds are any dust or whatever will be on those two inner elements.

 

[John51]

Best of luck, if it's between 2 elements cemented together it's hopeless, I would clean as far apart as you feel comfortable and try it. If it's not bad you probably won't notice. If it's on the perifery of the glass and not in the center at f 8 you won't see a thing. For 5 bucks it makes for an elegant paperweight

I use a non working M42 50mm lens as a workshop loupe. nbd if it gets sawdust/whatever on it as it's not worth anything.

 

[laser]

Separating groups from the iris assembly can be done with minor risk. However, disassembling glass elements that are held together with retaining rings risks the optical performance of the lens. The individual elements are not just dropped into the barrel and screwed down. They are precisely aligned and rotated on axis while being measured on an optical device. When they are positioned exactly in the optimum position the retaining ring is tightened, holding the element aligned within a seconds of arc. Less than optimum positioning can seriously degrade the optical performance on axis and across the filed. Unless the lens is useless to you with the dirt I would not disassemble the elements. The probability of you assembling it to equal factory quality approaches zero.

 

[John Galt]

Best of luck, if it's between 2 elements cemented together it's hopeless, I would clean as far apart as you feel comfortable and try it. If it's not bad you probably won't notice. If it's on the perifery of the glass and not in the center at f 8 you won't see a thing. For 5 bucks it makes for an elegant paperweight

Thanks mschem, actually at f8 the spot is right at the edge of the iris and at f11 it is covered, so it should be GTG . . ??

 

[tedr1]

When the lenses are secured by rings that have small slots at the edge the tool needed is a lens spanner wrench, they can be found on ebay and are inexpensive, search ebay.com for lens spanner wrench.

 

[mshchem]

Thanks mschem, actually at f8 the spot is right at the edge of the iris and at f11 it is covered, so it should be GTG . . ??

I would try it, I would have killed for that lens when I was a kid.