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Tools Of The Trade?


jginnane
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Two part question today ...

 

1.  Microscope 10x-100x for viewing diamonds:

 

ronk15a just mentioned his stereo microscope, a Gemolite Mark-V, in a thread about finding small inclusions in a stone. (American Optical Corp.)  There are 3 used Mark-V scopes on Ebay right now priced at ($830+66s/h), ($500+50s/h), and ($260+40s/h, with active bidding).  The last says Bausch & Lomb, so apparently there's been ownership changes of production.

 

GIA currently sells through its subdivision Gem Instruments a stereo microscope "PresentationScope 10x & 30x" (two objectives) with a list price of $795USD.  This seems to be the one they provide students as "affordable".

 

Stereo microscopes other than these two models are used throughout industry.  Apparently though, these are optimized for stone viewing.

 

What's best?  If you were replacing your tools today, would you buy either of the above, or something different?

 

 

2:  Jewelers' loupe set -- 10X, 30X, ?X?

 

This other category has all the Chinese knockoffs on Ebay, many with LED lights, for $3 or so.

 

It appears the standard objective lenses may be either 18mm or 25mm diameters. Some sets come with different powered lenses in the same twin-housing.

 

A few loupe descriptions mention the "triple-lens", which would be to correct for chromatic and spherical aberrations introduced by using a single glass element.

 

Again ... what's good?  What would be best at a budget of $50? At $100?  Is it worth it to pay more than that?  Or should one opt for clip-on lenses to go on a headband or eyeglass frame?  Are Carl Zeiss or Nikon optics worth the premium?

 

 

 

 

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I can't comment on the GIA microscopes - since I'm using a GEM-A one, and I have never used the GIA instruments to any significant extent. All I'd say is that for occasional, consumer use a microscope is overkill, even though it's interesting.

 

On the loupe, 10x is the de-facto standard because it is actually a good trade off between field-of-view and magnification power (as well as "10" being an easy number to remember). Get a good one - triplet and ideally a- if not apo-chromatic, however again paying hundreds for a Schneider or Swiss Hawk is in my opinion pointless if you are not a cutter. B&L or Zeiss make perfectly good lenses available for a fraction of the price, and even the Kassoy house-branded ones aren't at all bad, particularly for $40 or so. 15 to 20 mm is the norm; I have seen very few (and very expensive) 25 mm. While a larger lens will offer a greater field of view, the broader the lens, the more problematic spherical correction becomes, and often the theoretical extra field of view is totally unusable.

 

Clip on or "wearable" lenses aren't good unless you are a watchmaker - they distort significantly more since they (usually!) are not aspherical. Get a good hand-held loupe.

Edited by davidelevi
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My primary microscope is a Wild Heerebrugg M420 followed by a modified Nikon SZ10 with a GIA Mark V base.  I use a Nikon loupe when it counts but, 90% of the time I use a cheapo triplet that I bought from David Geller for something like $2/each.  Like bank pens, customers tend to steal loupes but, unlike bank pens, good ones are fairly expensive.  With a bit of practice, the cheap ones are actually pretty darned good. 

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Thanks for the input.  After a bit of hunting, I bought a 2-pack of a 10X Triplet and 20X Quadruplet Belomo loupes from Ebay for $70, incl lanyards and shipping.

 

The legendary Schneider loupe I'd heard of, but wasn't in the mood to pay $350-400+ used for the amount of wear I'd give it in this lifetime.  Nikon, Zeiss and Bausch & Lomb were all close contenders, but I didn't run across deals as good as the one with Belarus optics.  As Neil says, loupes have a tendency to walk away.

 

Kassoy has a 2-objective lighted loupe (10x and 14x) for $36 at --

 

http://www.kassoy.com/kassoy-led-uv-10x-14x-20x-lighted-loupes.html

 

--which I would have gotten if there were any issues with the Belomo purchase.  The UV LED is cool, esp. for the kind of crap stones I wind up buying.  However, I tend to leave these things on the shelf until the batteries run out, then it's always a painful run to the nearest Radio Shack for single-battery purchases.

 

A stereo microscope is a possible/likely future purchase, but I'd forgotten how big these are. With these, the trick isn't the most powerful optics, but adaptive use, which nowadays means swapping in a USB optic imager for one of the eyepieces.  Guess I'll watch the Craigs List market. :)

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Craigs List finds ...CARL ZEISS JENA antique MICROSCOPE bronze JENA medical stand D, type S - $5000

post-134047-0-74112800-1403754176_thumb.jpg

 

This puppy's available in NJ if anyone's interested. :)

 

Quoting -- "This is the Rolls Royce of all microscopes! 1926 deco antique early Zeiss binocular Microscope. Blue glass filter. Magnifies great! What a beautiful microscope.

"https://www.etsy.com/listing/185381330/1926-binocular-carl-zeiss-antique?"

 

 

 

(PS -- NOT an antique, until it's 100 years old.)

Edited by jginnane
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Looks nice, but... lighting is the devil in the detail.

 

Yup ... personally, I wouldn't have time just to keep the brass clean.

 

 

This Leica -- Leica Galen III Trinocular Microscope - $975 (Lower Bucks) -- at

 

http://philadelphia.craigslist.org/bfs/4521543843.html

 

-- is almost affordable, and a terrific value, and SO tempting.  Trouble is, I've only started my list of things I can do with a good microscope and the page isn't quite full yet.

 

Perusing used microscopes is a little like looking at 1960s-era IBM 370 tape drives; there's a priesthood involving all the tech specs and you're keenly aware that YOU weren't part of it at the time. I can do better with Underwood typewriters. :)

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The #1 secret to gemological microscopes has to do with the light well.  That's the area behind the stone with a dark field behind.  They're actually kind of unusual in the microscope world.  You can retrofit optics onto bases with a darkfield well but you really do want one.  If you're decently handy, you can buy them on ebay but it's not completely trivial to make it work right, 

 

#2 has to do with the optics.  Glass is way better than plastic.  Plastic is generally cheaper.  Nearly all new ones are pure plastic and you find that the old GIA Mark-3's are actually very nice tools.   I much prefer the Leica optics to the B&L ones and I prefer both to the generic lenses they use now.  good optics are a lot easier to find than a good base. 

 

#3.  Personally I really like having a trinocular.  That's a 3rd port you can stick your camera in.  You CAN take out one of the occulars and replace it with a camera, and you CAN get a decent picture this way, but it's an enormous pain and takes a fair amount of practice.

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The #1 secret to gemological microscopes has to do with the light well.  That's the area behind the stone with a dark field behind.  They're actually kind of unusual in the microscope world.  You can retrofit optics onto bases with a darkfield well but you really do want one.  If you're decently handy, you can buy them on ebay but it's not completely trivial to make it work right, 

 

#2 has to do with the optics.  Glass is way better than plastic.  Plastic is generally cheaper.  Nearly all new ones are pure plastic and you find that the old GIA Mark-3's are actually very nice tools.   I much prefer the Leica optics to the B&L ones and I prefer both to the generic lenses they use now.  good optics are a lot easier to find than a good base. 

 

#3.  Personally I really like having a trinocular.  That's a 3rd port you can stick your camera in.  You CAN take out one of the occulars and replace it with a camera, and you CAN get a decent picture this way, but it's an enormous pain and takes a fair amount of practice.

 

Hi Neil,

 

http://www.microscopyu.com/ is a Nikon-sponsored website that explains things like darkfields.  But it also raises a serious question:  if CCD technology is now quite advanced (but still rapidly improving), at what point do you skip optical tubes altogether?

 

I got rid of my darkroom and film cameras almost 20 years ago in favor of digital cameras. But then, after some major improvements in digitals, my first two big equipment buys were rendered obsolete in a matter of months.  I decided to resort to  simple point-and-shoot cameras until it appeared that digital technology was hitting a plateau.

 

20-megapixel cameras are the "prosumer" range today but you can buy a P+S 16Mp for under $300.  Macro focus modes on cheap P+S cameras is quite good, though you usually need to defeat autofocus (and auto- everything else) to achieve decent results.

 

HOWEVER, when it comes to microscopy, shopping the cheapies is not so rewarding -- they'll be happy to stick you with a 1.3mp camera if you want a completed product (ie, stand and lights).  And good luck if your lighting requirement is anything more than an 8-LED light array.

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Cameras aren't so different.  I went digital decades ago for a variety of reasons and am definitely not going back.  I'm on something like my 6th generation of digital equipment.  It's still about the glass.  I use a $900 lens for most of my work although I've changed the body twice since I bought it.  There's STILL nothing better on the market for what I do.  It ain't about megapixels. 

http://www.bhphotovideo.com/c/product/424744-USA/Nikon_2160_105mm_f_2_8G_ED_IF_AF_S.html

 

 

It's an intriguing problem that when I upgrade the body, I'm now locked into the Nikon brand.  It's not that Canon doesn't make find products, but they don't fit my lenses.  The same would be true if I upgraded a lens.  I've got Nikon bodies and if I switch to Canon, I am effectively abandoning my entire setup for a different version of exactly the same problem.  I've been in this situation for at least 20 years and nearly everyone who is serious about cameras has a similar problem.  

Edited by denverappraiser
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It's an intriguing problem that when I upgrade the body, I'm now locked into the Nikon brand.  It's not that Canon doesn't make find products, but they don't fit my lenses.  The same would be true if I upgraded a lens.  I've got Nikon bodies and if I switch to Canon, I am effectively abandoning my entire setup for a different version of exactly the same problem.  I've been in this situation for at least 20 years and nearly everyone who is serious about cameras has a similar problem.  

 

Back when I had to make my decision, I had a good Nikon body, flashes, an autowinder, 4 good lenses, a bunch of other stuff ... about $4-5K in purchases.  Nikon only provided an upgrade for the top of the line SLR, the F4.  Not for my equipment.

 

Instead of Craigs List, Ebay, or selling back to B&H, I took everything, put it in my garbage, and placed it out at the curb.  I vowed never to get trapped again.  (I also got rid of my early Nikon digital SLR the same year.)

 

[ Parenthetically: Now in 2014, I can buy a Nikon F4 film body and some great lenses for the price of a couple CF cards. I could, if I chose, also rebuild my darkroom for pennies on the dollar.  But I don't think it'll happen.  I was lucky enough to dump my EK stock when it did a dead cat bounce from ~60 to $85, and I got out before the price settled back on its inexorable downward spiral to oblivion. ]

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