Geologist/Jeweler magnifier as loupe--and amazing tool

[Michael Kadillak]

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]

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]

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]

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]

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]

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]

This discussion proves what I have thought for a long time. Loupe selection is a very personal matter.

[Arne Croell]

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.