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Photo Forum / Film Photography / Darkroom / May 200760mm/5.6 componon in a strange mount
Hi All, A few years ago I bought a number of enlarging lenses on eBay(where else?). One of them is a 60mm componon lens. However, it has been screwed tightly into a much larger metal cylinder that has 50mm diameter, and the 50mm cylinder is threaded on the outside. I tried to retrieve the "original" lens so that I can use it in my enlarger, but it is very tightly sitting inside the 50mm cylinder that I could not get it out. Have any of you come across a mount that can accept a 50mm threaded lens? I am curious to know what this lens was used for. The 50mm cylinder is quite deep(thick?), about an inch, so I suspect it was used for focussing. Any information about this lens is appreciated, thanks in advance, Sreenath > 60mm componon lens ... has been screwed > tightly into a much larger metal cylinder that > has 50mm diameter, and the 50mm cylinder is > threaded on the outside. [It's stuck.] > [What is this?] Some large enlarging lenses, 150mm Rodagons at the least, come in 50mm mounts. They are sometimes screwed into 50mm->39mm reducers so they can be mounted in standard 39mm holes. This is the first I have heard of a 39mm->50mm adapter. It is quite possible this lens was used for other purposes - scientific, industrial - and hence the adapter. If the lens mount and the adapter are both anodized aluminum then it is not surprising they are stuck together. Try a drop of WD-40 or Liquid Plumber around the crack between the lens and the adapter. Rap the adapter sharply with a small hammer every day or so until they come apart. To take it apart faster you can try the oil & rap above and then boil a pan of water, stick the adapter end into the hot water to heat it up and then rapidly pull it from the water and unscrew. Wear gloves. Only have a 1/2" or 1" of water in case you drop the lens. It is possible the hot water trick will work with hot water from the sink. My lens, it got de wrong hoe Oil, rap and boil, huh!  SignatureNicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/index.htm n o lindan at ix dot netcom dot com > Try a drop of WD-40 or Liquid Plumber around the crack > between the lens and the adapter. Rap the adapter > sharply with a small hammer every day or so until > they come apart. I think Liquid Wrench would be better. > Nicholas O. Lindan miss-wrote: > > Try a drop of WD-40 or Liquid Plumber > I think Liquid Wrench [penetrating oil for plumbing > pipes] would be better. Uh, yes, thank you. Liquid Plumber, lye, would be a _very_ bad choice. Liquid Wrench is indeed the stuff to use. SignatureNicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/index.htm n o lindan at ix dot netcom dot com Hi, thanks for all responses. I forgot to mention that the "original" lens has a 25mm diameter, the standard used by Schneider for some of its enlarging lenses. So this is converting a 25mm/0.5mm thread to 50mm thread with a pitch of approx. 1mm. --- Sreenath > > Nicholas O. Lindan miss-wrote: > > > Try a drop of WD-40 or Liquid Plumber [quoted text clipped - 10 lines] > Darkroom Automation: F-Stop Timers, Enlarging Metershttp://www.darkroomautomation.com/index.htm > n o lindan at ix dot netcom dot com Nicholas O. Lindan spake thus: >>Nicholas O. Lindan miss-wrote: >> [quoted text clipped - 7 lines] > > Liquid Wrench is indeed the stuff to use. Better yet, to avoid the possibility of oily substances migrating to lens surfaces, I'd use acetone/lacquer thinner instead, injected with a syringe. This has loosened all kinds of threaded stuff for me. The rest of Nick's advice (several days, rapping w/hammer) is good. SignatureAny system of knowledge that is capable of listing films in order of use of the word "f.ck" is incapable of writing a good summary and analysis of the Philippine-American War. And vice-versa. This is an inviolable rule. - Matthew White, referring to Wikipedia on his WikiWatch site (http://users.erols.com/mwhite28/wikiwoo.htm) > Hi All, > [quoted text clipped - 19 lines] > thanks in advance, > Sreenath It might be the 60mm is a wide angle lens and the mount is to allow additional clearance to prevent cutoff. gr > Hi All, > [quoted text clipped - 19 lines] > thanks in advance, > Sreenath You could also just get a new lensboard tapped for 50mm threads.I use a Beseler 45MXT and I keep all my lens on separate boards for quick changes. Glenn Booth >> Hi All, >> [quoted text clipped - 24 lines] > > Glenn Booth It's possible that the lens was used in a minilab. My minilab has twenty different enlarger lens in various focal lengths (and brands), each one mounted in a barrel that fits into the lens box. The distance between the negative and the paper can't change, so if I want to print a wallet size print from 35mm, I use one particular lens; if I want to print 8x10 from 6x7 negatives, I use a different lens. The location of the lens inside the barrel eliminates the need to focus (since you can't really focus a minilab). It could indeed be a mini-lab lens, many used Schneider optics. The 50mm barrel could be a focusing mount. BTW the operator doesn't focus a mini-lab but the lab manager or installer can using a piece of ground glass at the easel position inside the printer. Most of the time the lenses then get locked down so that there's no need to refocus whenever the operator changes "setups" to print a different size. darkroommike >>> Hi All, >>> [quoted text clipped - 33 lines] > lens inside the barrel eliminates the need to focus (since you can't really > focus a minilab). > It could indeed be a mini-lab lens, many used Schneider > optics. The 50mm barrel could be a focusing mount. BTW the [quoted text clipped - 43 lines] > > lens inside the barrel eliminates the need to focus (since you can't really > > focus a minilab). Thanks again for the information. I have found a workshop nearby that will make a lens board with a 50mm thread in it. I will be able to use it in my enlarger. It may be easier to "critical-focus" with the lens thread. rgds, Sreenath |
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