loupe purchase advice

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Dale
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loupe purchase advice

#1 Post by Dale » Tue Feb 09, 2016 10:42 pm

There are hundreds of these things, with wildly varying opinions, but I trust my forumist's
advice. Specificaly these factors:
min max magnification
singlet doublet triplet
diameter
illumination
glass vs plastic lens
I'll be using it outdoors on vegetation, minerals, dirt, stagnant water, you name it! I like
quality stuff. Would carry it everwhere, and I travel a lot. If I'm going to get malaria
I want to see the little sucker that is biting me!!
Dale
B&L Stereozoom 4. Nikon E600. AO Biostar 1820.

billbillt
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Re: loupe purchase advice

#2 Post by billbillt » Tue Feb 09, 2016 10:51 pm

Hi Dale,

I have one of these:

http://www.ebay.com/itm/5X-7X-9X-20X-Ba ... 597fa5:g:g

It is very high quality and works great for me...

BillT

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lorez
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Re: loupe purchase advice

#3 Post by lorez » Tue Feb 09, 2016 11:00 pm

Once upon a time I'd have said, "you can't go wrong with B&L", but that was a long time ago. They left the microscope business and on their final models there were several that were purchased from other factories. It could be that the current product is such an item. If Bill is using it successfully, that is the best recommendation.

lorez

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zzffnn
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Re: loupe purchase advice

#4 Post by zzffnn » Tue Feb 09, 2016 11:35 pm

I would like to know this too. What is the recommended (or realistically usable) upper limit of a quality loupe? 20x?

As a reference, I use microscope eyepieces no more powerful than 15x.

I heard microscope eyepieces, used in reverse, can serve as quality loupe. So a good 15x EP, used in reverse, makes a good 15x loupe? But isn't the field of view limited with reversed EP? I imagine dedicated loupe at 15x should have better FOV?

Do those Belomo loupes work well?
Selling my Canon FD 200mm F/2.8 lens

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gekko
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Re: loupe purchase advice

#5 Post by gekko » Wed Feb 10, 2016 12:24 am

I have a triplet loupe similar to this 20x and it is excellent.
http://www.ebay.com/itm/20X-Black-Hex-M ... Swa-dWouZH
Another source (I think this is where I bought mine from):
https://www.widgetsupply.com/product/BCU23.html

I think 20x is about the highest practical magnification with a loupe.

I was enticed by the B&L designation and bought a couple of different inepensive ones on ebay and found that they were as lorez indicated: cheap knock offs with very poor quality, distort badly near the edges, and were simple plastic lenses (I assumed that since they were plastic they would be aspheric, but I doubt that).
Last edited by gekko on Wed Feb 10, 2016 1:06 am, edited 1 time in total.

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KurtM
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Re: loupe purchase advice

#6 Post by KurtM » Wed Feb 10, 2016 12:52 am

I have been using loupes since the late 70's for photography (back when we would examine slides, negatives, and prints), rock & minerals, and for just about anything and everything else. Have also seen a zillion loupe discussions of forums. It's one of those things where if you ask ten people, you get fifteen opinions. But there is one that comes up more often than all the others, and it's the Belomo. Because of this, I bought one about five years ago, even though I thought I was just about done buying loupes -- I must have at least two dozen laying around, plus who knows how many I threw out because they were so awful.

The Belomo is the only one I use now.

One thing a lot of people seem to be unaware of: when using a loupe, hold it right up to your eye to look through it, don't try to use it like a Sherlock Holmes magnifying glass. Except for those that are designed to be used that way, and some are, but you'll know 'em when you see 'em because they have little stands built into them. But even they work better held close to the eye.

Fan, I routinely use reversed microscope eyepieces to check lenses, it's a hoary old time-honored "lab trick"; in fact the old Spencer and AO catalogs specifically instruct the user to do so. Guess I could grab my loupe, but an eyepiece is always right there.
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gekko
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Re: loupe purchase advice

#7 Post by gekko » Wed Feb 10, 2016 1:05 am

Thank you Kurt: I never heard o Belomo, but it appears to be a very high quality, coated loupe. It appears to have a rather small field of view (but I am guessing there).
Yes, when I was working people always wanted to use the eyepiece of my microscope for that purpose (I tried as best as I could to discourage them as I didn't fancy leaving the eye tube open to dust :( )

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zzffnn
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Re: loupe purchase advice

#8 Post by zzffnn » Wed Feb 10, 2016 1:44 am

Thank you very much, Kurt. Belomo's reputation does seem to be consistent.

Does your Belomo have a small apparent field of view, how do you feel about it when comparing it to a 15x microscope EP in reverse?
Selling my Canon FD 200mm F/2.8 lens

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Dale
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Re: loupe purchase advice

#9 Post by Dale » Wed Feb 10, 2016 3:23 am

The Belomo looks great. I'll just use my 10 15 and 20X ep's to pick a power.
Really nice respose, thank you all.
Dale
B&L Stereozoom 4. Nikon E600. AO Biostar 1820.

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KurtM
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Re: loupe purchase advice

#10 Post by KurtM » Wed Feb 10, 2016 5:20 am

I did a little messing around to see if I could answer some questions. First, I tried a reversed 15x eyepiece as a loupe, and found it a pretty poor one with tons of spherical aberration, only sharp in the center 1/3 or so. Next, I compared the 10x Belomo loupe to a couple of 10x microscope eyepieces, and just for the record, both the Zeiss and AO 10x eyepieces performed more or less identically as loupe stand-ins. They made better loupes then the 15x ocular, but the Belomo still had 'em beat hands down with bright views that are sharp almost all the way to the edge, if not quite. BUT, I was somewhat surprised to note that the reversed 10x eyepieces magnified noticeably more than the Belomo 10x loupe. Don't ask me why, I'm just tellin' ya what I saw - and I double and tripled check to make sure of this.

Seems like a couple of you asked about the field of view. Yes, it has a field of view. :P I have no idea how to answer the questions other than that. What's the field of view like ... compared to what? I guess I can say it never struck me as either unduly restricted or breathtakingly wide, if that helps at all.

I'd say for $30 it's worth it, especially since you can fold it up, stick it in your pocket along with your key ring, change, and pocket knife, and it'll emerge fresh as a daisy every time no matter how long it's been in there. Even the paint job's pretty tough, mine still looks brand new and it's been known to live in my pocket for weeks at a time.
Cheers,
Kurt Maurer
League City, Texas
email: ngc704(at)aol(dot)com
http://sawdustfactory.nfshost.com/microscopes/
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gekko
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Re: loupe purchase advice

#11 Post by gekko » Wed Feb 10, 2016 11:26 am

Thank you, Kurt. Good to know.

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zzffnn
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Re: loupe purchase advice

#12 Post by zzffnn » Wed Feb 10, 2016 1:56 pm

Thank you very much, Kurt. Your comments are very helpful.

I was basically asking if the Belomo loupe can project a good image cone that is wide and high enough for eyeglasses use.

I wear strong prescription eyeglasses and they demand wide field high eye point eyepieces. I tried regular eyepieces like the following, but my eyeglasses could not get used to them (because their apparent view field is too small - I have to take off my glasses to use them, but then my naked eyesight is terrible):
http://m.ebay.com/itm/Pair-compensating ... 2006059435

My eyeglasses can only work with wide and high eyepoint eyepieces like these:
http://m.ebay.com/itm/AO-10x-W-F-Cat-14 ... 0867892085

The above pairs of eyepieces are otherwise quite close to each other optically, but the AOs are more comfortable to use due to their wider apparent view field.

Without help from a fellow eyeglasses-wearing microscopist, I usually just judge by top lens size (larger usually works better), though it may not be the most accurate way.
Selling my Canon FD 200mm F/2.8 lens

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KurtM
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Re: loupe purchase advice

#13 Post by KurtM » Wed Feb 10, 2016 4:46 pm

For my money, it's best to always go with the widest field, highest eyepoint oculars available whether you wear glasses or not.

But to answer your question, I can't see where you'd have any problem with the Belomo. I use mine while wearing my readers, and just now tried it again to be sure before posting this and found it offering a perfectly fine view two to three inches away from my eye. Now if your specs are thicker than that, I'm afraid you're on your own. :shock: :lol:
Cheers,
Kurt Maurer
League City, Texas
email: ngc704(at)aol(dot)com
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Re: loupe purchase advice

#14 Post by zzffnn » Wed Feb 10, 2016 10:03 pm

Thanks a lot, Kurt.

I looked at a petri dish just now with reversed a 10x eyepiece. I think protozoologists would probably prefer 20x Belomo. Reversed 10x EP is about right for ostracods and water fleas, but a bit too low for big parameciums.

For bigger insects, 10x loupe is probably better. But hey, most people here would probably get both - might as well buy them at the same time to save on shipping cost.
Selling my Canon FD 200mm F/2.8 lens

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Dale
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Re: loupe purchase advice

#15 Post by Dale » Mon Feb 22, 2016 8:54 pm

The Belomo is awesome. Have not compared it to any oculars as I am not going
to carry one of them across Africa. I read so many reports from people who
downgraded this loupe because they could not fasten a neck lanyard! Words fail me.
Thanks for all the advise leading to my 4th, if not more, happy purchase.
Dale
B&L Stereozoom 4. Nikon E600. AO Biostar 1820.

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