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View Full Version : Geologist/Jeweler magnifier as loupe--and amazing tool



Darin Boville
8-Jun-2009, 16:37
Reading through the forums I came across several people mentioning that they use a geologist's magnifier instead of a loupe. Intrigued, I found a very affordable one here:

http://www.amateurgeologist.com/belomo-10x-triplet-loupe-magnifier.html

It just came in today. What a cool gizmo! It is built like a tank, small and the optical quality seems very high. I'm not 100% sure I'll use it as a loupe--not much nose clearance so I'll have to experiment--but this is a "must have" item, I think, for all hikers and explorers.

So much better than the expensive Schneider I had--nice but broke easily (it was plastic).

I always encourage people to carry a pair of binoculars for the way it enhances the visual experience of the outdoors--now I'm going to also highlight this little 10x magnifier--sort of like a field microscope hanging around your neck. Hopefully I can find a way to make it work as a loupe as well.

Only $30, too

--Darin

Gem Singer
8-Jun-2009, 17:25
10X--- too strong to use as a ground glass focusing a loupe.

Darin Boville
8-Jun-2009, 17:43
10X--- too strong to use as a ground glass focusing a loupe.

Well, then you may like this one at 7x:

http://www.amateurgeologist.com/BelOMO-7x-triplet-loupe-magnifier.html

--Darin

Archphoto
8-Jun-2009, 18:09
The Russians make some good optic's, that's for shure.

I use a coated T-3 2.8/80mm projecter lens as magnifier and it works great.
Got that one when the russian importer in Holland went bust years ago.

Peter

Gem Singer
8-Jun-2009, 18:43
7X is still quite strong to use for ground glass focusing.

In the case of a focusing loupe, stronger magnification is not necessarily better. (Unless you are interested in examining the grain structure of the ground glass or the lines of a Fresnel screen).

In order to focus those geological loupes, you need to continually move the loupe forward and backward in order to maintain sharp focus. That can become very annoying when you are under a dark cloth making adjustments to the camera.

A loupe that is specifically designed for ground glass focusing rests directly against the glass and has a dark skirt surrounding the front element to keep out the stray light.

Michael Kadillak
8-Jun-2009, 19:20
I have a couple of Zeiss loups from college and used them once for LF photography. They went back into the case where I got them after the first usage. Constantly searching for the optimum focal length to hold the loup away from the GG is a PITA.

There are really only three options here IMHO. The first is to use your eyes (or reading glasses depending upon your age) for focusing and learn to see things in a "relative" perspective. It works marvelously well and many seasoned professionals utilize it . Second is to use not more than a 4x loup that resides on the ground glass so it is easy to place it where you want to and get on with things. Lastly is to use the opti visor head gear loup that you drop into place when you need it.

If you are using the 4x5 or smaller formats the 3.5X Toyo loup is a great and inexpensive alternative. Cost about $30 - $40. For 8x10 and larger one can be easily go with the naked eyes without a loup. Remember, many times optimum focus is a consistent improvement in the image area that can only be seen en masse. Lastly, if you are doing macro in all formats the opti visor is the boss.

Cheers!

Greg Lockrey
9-Jun-2009, 01:36
While I agree with Michael about the PITA with using magnifiers for focusing the site you referenced is pretty cool to this former "rockhound". I had a really nice multi-power I bought in Italy that I been meaning to replace. Now I can....

Steve Barber
9-Jun-2009, 05:53
The Russians make some good optic's, that's for shure.

I use a coated T-3 2.8/80mm projecter lens as magnifier and it works great.
Got that one when the russian importer in Holland went bust years ago.

Peter

I use a 50mm El-Nikkor, but any brand would do. This is, by far, the best thing I have found for focusing on the ground glass.

Since you look through the "front" of the lens, it is no problem to thread a piece of PVC to the lens to use for a skirt, if you want. I prefer not having a skirt. This allows me to use the lens with or without my reading glasses without having to adjust it.

I paid $20 for mine, in mint condition with its cap. I would guess that there are plenty of other enlarging lenses around that are still more than adequate for the job and can be had for even less.

Robbie Shymanski
9-Jun-2009, 19:08
Umm.. I have a 6x "jeweler's" loupe I got from the hardware for $3. It is all plastic and works like a charm. And should I loose it, I know where to get more and I am really not out that much. Plus, you look like a badass when you keep it in your eye and then drop it in your palm.

sun of sand
10-Jun-2009, 03:57
I use 3 diopters together +6 or +7
Doesn't bother me any. Sharpness? Sharp enough in the center. Who cares if not sharp to the corners? No skirt ..I wouldn't want to keep hitting the camera when placing on gg ..seems sloppy to me. I don't get tired shifting my head ever so slightly for a few tenths of a second. Maybe if you have a really weak neck it's a PITN. I see well enough to not use any at all. I really don't even need a grain focuser in the darkroom ..I'd put it to a test.
My favorite "loupe" for 35mm negatives etc is a lens element out of some old camera. I have a B&L triplet thing and linen tester and plenty of others but that element always wins.
I personally have no idea why someone would pay $80 for a loupe
But then I've seen lots of people look the part only to find out ..they only look the part.
Not saying that's 100% of these $80 loupe people but I certainly believe a strong 30%

Michael Kadillak
10-Jun-2009, 06:13
Sharp enough in the center. Who cares if not sharp to the corners? No skirt ..I wouldn't want to keep hitting the camera when placing on gg ..seems sloppy to me. I don't get tired shifting my head ever so slightly for a few tenths of a second. Maybe if you have a really weak neck it's a PITN. I see well enough to not use any at all. I really don't even need a grain focuser in the darkroom ..I'd put it to a test.


Sharp enough in the center? How do you know if your plane of focus is in the correct position?

Obviously you are free to allocate your photographic intellect as you see fit for yourself and that is all well and good but for the purposes of those that may come along and read this at some future point in time thinking it is acceptable I just want to say that it is ABSOLUTELY NOT.

Simply put LF and ULF cameras have movements that need to be properly utilized and in the correct position to attain a sharp negative and print. Checking the GG corners for sharpness is mandatory and using a loup on it will have absolutely no adverse effect whatsoever. Photographers have been doing it for many many years as a SOP.

Factually speaking the GG is your responsibility to do with it as you see fit. To not accept this responsibility for the investment in time, film and results no matter the format is just being lazy. What if you have to put a swing into your photograph? What about a macro shot? Is that good enough in the center as well? Please.

When you shoot 8x10 and larger and the price of the film as well as the lack of attention catches up with you you will either step up to the plate and be a real LF and/or ULF photographer of get a Holga and call it good enough.

Dan Schmidt
10-Jun-2009, 07:27
Sharp enough in the center? How do you know if your plane of focus is in the correct position?


I think the previous poster meant that his form of magnification was sharp in the center and then he moves it around the ground glass to check sharpness of the whole image on the GG.

Michael Kadillak
10-Jun-2009, 08:44
I think the previous poster meant that his form of magnification was sharp in the center and then he moves it around the ground glass to check sharpness of the whole image on the GG.

If that is the case then the author can correct this himself.

I took this in the context of a number of other related comments that were made and hope that I am wrong.

clay harmon
10-Jun-2009, 10:52
Yeah, its pretty clear to me that he meant that the DIY loupe was only sharp in the center.


I think the previous poster meant that his form of magnification was sharp in the center and then he moves it around the ground glass to check sharpness of the whole image on the GG.

Charles Young
10-Jun-2009, 12:37
As a geologist I can tell it's much nicer to examine a rock with my scheneider 4x loupe than with my regular magnifier - FOV is wider and it's much more comfortable...

cheers,

Charles

www.paisagembrasileira.com

sun of sand
11-Jun-2009, 02:33
I shouldn't have said corners so I can see both sides of it
but since was talking only about loupes and not film or GG it does seem to be a bit of a jump to make it over there

Ernest Purdum
11-Jun-2009, 15:57
This discussion proves what I have thought for a long time. Loupe selection is a very personal matter.

Arne Croell
12-Jun-2009, 14:59
Since I was probably one of the people using a geologist loupe Darin was referring to, I'd like to add a few comments. Note that I also own a a regular Schneider loupe for GG viewing as well as an EMO loupe of similar construction, so I've used them all, but prefer the Geologists loupe.

1. I use reading glasses with 3.5 diopters for composition and general focusing, then I use the geologists loupe for critical focusing in the most important areas. A large FOV is thus not that important to me. Note that the FOV differs between makes at the same magnification.
2. The maximum magnification that works depends on the ground glass type. I use a Bosscreen which is virtually grainless and 7x, 8x or 10 x is no problem. I've even used a 15x when I focused a few lenses for testing.
3. There are geologist loupes with smaller magnifications (e.g. 6x), often as combination loupes (3x + 6x=9x). Eschenbach and Zeiss make some.
4. I have no problem keeping the GG in focus (maybe except for the 15x), its second nature for me to adjust my head position to keep things in the desired focus.
5. For me, the fact that I do not rest the loupe on the GG is an advantage, as I a) do not shift the GG position by applying pressure, b)easily tilt the loupe to get better illumination in the corners with wide angles, and c) can even check the outmost corners which is not possible with a regular loupe resting with its base on the GG.
6. Ernest is certainly right, it is highly individual.