I’ve been into stones and crystals again lately, and realized suddenly that I don’t have a jeweler’s loupe to look at them with. This is a little odd considering that I’ve been playing with rocks since I was 6. But whatever.
If you’re intrigued by the idea of opening new vistas of time-wasting by examining objects (rocks, jewelry, printing…) with a loupe, what I’ve learned follows. If you aren’t, this is like the dullest post evar.
I thought getting a loupe would be fairly straightforward, but in trying to pick one out, I entered a dark, shady world. What I’ve learned, in no particular order:
most are made in China, are labeled as “triplets” (three lenses) but are not, and are sold for as low as $0.89 but often up to $10 for the same models;
according to most reviewers, these cheapies are occasionally useful if you happen to get a good one;
for the cheapies as well as some of the slightly nicer ones, the magnification isn’t really as high as the label states;
the gold standard for loupes is Bausch and Lomb, which run about $40 and up for 10x triplets;
if you want to spend even more on one, you can buy a Nikon or a Zeiss;
like most things, different stores sell the exact same products for wildly different prices;
the most effective standard lens arrangement is a set of three (“triplet”), but a single lens cut “coddington” style can also work well;
the standard magnifications are 10x and 20x, but there are some weird ones like 7x or 14x;
lens sizes are generally 18mm or 21mm, but with some weird ones like 20.5mm;
there are dozens of combinations of size, magnification, and case shape so that there is a dazzling array of choices;
there is very little advice to be found from the sellers of these items on what magnification and size you need for what you’re doing.
Some sites point out that jewelry appraisers use 10x, and anything you see under higher magnification doesn’t count on the appraisal. Since I didn’t plan to use it for jewelry appraisal, this wasn’t much help. And it still didn’t tell me why some were 18mm and others were 21, or what the effective difference between using 10x and 20x was. Didn’t I just want a 20x, 21mm model?
Hahaha. Eventually I found a couple of sites explaining that the field of view of a loupe is never really more than 18mm, so it doesn’t matter whether the lens is larger or not – the extra space around the edges is fuzzy; and that the problem with 20x magnification is that the depth of view shrinks and you have to get so close to the object that you tend to block out all the light, although it can be interesting to use and nice to have one on hand.
Here are the two sites that I found the most useful:
Considerations when selecting a loupe
How to choose a loupe or magnifier… and where to buy
Wikipedia, about.com, eBay guides and the like all had bits of information but in general weren’t that helpful.
When I finally got into the reviews, people who had seriously compared loupes always liked something called the BelOMO 10x the best. At the time most of these reviews were written, it seems the BelOMO could be had for $15, but the manufacturer (in Belarus) steeply raised the price recently – not that I can blame them since it sounds like they were way underpriced before. Now the list is $30, most sellers have them for about $24, and the best price is from amateurgeologist.com for $20. Since they’re compared favorably with the equivalent Bausch and Lomb model ($40…), I think it’s still a winner and that’s what I’m planning to get.
I probably will want a 20x as well at some point, but not only are they more expensive, since they aren’t as widely used they’re harder to find reviews of, and since they’re more complex technically the cheaper brands may not even work well enough to bother with as compared to a good 10x.
By the way, while you’re at the Amateur Geologist store site, it’s worth poking around. In addition to things you would expect like rock hammers and lapidary equipment, they also have educational posters such as “A Collated History of Matter,” Indiana Jones-style field bags and vests, and a travel mug that says “I heart rocks.”