| Author |
 Replies: 9 / Views: 2,750 |
|
|
Pillar of the Community
United States
4038 Posts |
Over on another forum there is a thread asking what is the best loupe for coin viewing. There were the usual responses, ie B&L 7x Hastings Triplet, Zeiss Doublets, etc. Of course standard doublet or triplet magnifiers pale in quality by comparison to most any enlarger lens. A 50mm enlarger lens can be found dirt cheap compared with the B&L (and especially the Zeiss), has much better correction for color and distortion, and is approximately equivalent in magnification to a 6-7x loupe. I wrote my suggestions and at first I heard crickets, then got the chiding response "the OP was asking about loupes, not camera lenses". So my question is if anyone here is using enlarger lenses this way, or am I just too far out there even for folks in the know?
|
|
|
|
Pillar of the Community
Canada
4227 Posts |
A coin dealer in Nova Scotia I used to work with loved using his lens (don't know any specifics) and upon trying it once, thought it worked great. Easy to handle and seemed easy on the eyes. I just never really knew where to get one or what really to look for, but may look harder now.
|
|
Pillar of the Community
United States
2373 Posts |
I don't know if it qualifies but while at my desk I use the eyepiece off a variable power scope that didn't survive the crash. nlp
|
|
Pillar of the Community
 United States
4038 Posts |
Not the same thing...I know a lot of collectors and dealers who use eyepieces as loupes, and they tend to be quite good quality. But they are a completely different animal than an enlarging lens.
In microscopes, there are two basic optical elements: the objective, and the ocular. The objective is the lens that faces the object, while the ocular faces your eye. Objectives usually set the overall magnification and quality of the image. Oculars (eyepiece)magnify the image created by the objective and match it to the requirements of your eye (field of view, distance between lens and eye, etc). Problem is that the design of the ocular is usually such that it must be used "backward", ie so the end that is supposed to go toward your eye actually goes toward the viewing object. Thus it is being used in a reducing mode, rather than magnifying as it was intended, and the image quality suffers. That said, I have a bunch of eyepieces around and they do make good magnifiers!
|
|
Bedrock of the Community
United States
14454 Posts |
I use the eye piece off of an old microscope as a loupe most of the time. I am guessing it is 20 or 30x because it has a lot more magnification than the 10x loupe I use as well
|
|
Pillar of the Community
United States
4038 Posts |
It may be your eyepiece is a "true" 10x while your 10x loupe is a "marketing" 10x.
Diatribe follows...Most eyepieces are 10x, and it's quite uncommon to find any that are higher than 15x. This is because the overall image quality starts to suffer beyond this point due to what the microscopists call "empty magnification". If you want to double your magnification with high image quality, you won't get there by doubling your ocular power. You need to double your objective power because doubling the ocular magnification halves the effective aperture. It's the same optical effect as adding a 2x teleconverter.
|
|
Pillar of the Community
United States
9792 Posts |
I use an old Schneider film loupe, designed for medium format negatives and slide viewing on a light box, ti's pretty big, almost 3" of glass - makes it easy on my old eyes.
"Buy the Book Before You Buy the Coin" - Aaron R. Feldman - "And read it" - Me 2013! ANA Life Member #3288 in good standing since 1981, ANS, Early American Coppers Member (EAC), Colonial Coin Collectors Club member (C4), Conder Token Collector Club member (CTCC), Civil War Token Society (CWTS) member, Liberty Seated Collectors Club (LSCC) & Numismatic Bibliomania Society member (NBS), USMex, Member in good standing, 2¢ variety collector. See my want page: http://goccf.com/t/140440 |
|
Valued Member
United States
51 Posts |
|
|
Pillar of the Community
United States
4038 Posts |
That reduction fitting stand is brilliant, love it.
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
|
Valued Member
United States
51 Posts |
rmpsrpms, thank you. It seems to work well.
|
| |
Replies: 9 / Views: 2,750 |
|
Posted 03/02/2013 1:02 pm
