40x6b

Chujybear · Feb 9, 2015

What's meant in microscope language by the numbers on the ocular lens. I know the common recommendation is 10x21b. But I don't know what it means.
So when the scope says eyepieces are 40x6b, for instance, what are they saying?

mitch · Feb 9, 2015

iirc, 40x is the magnification, 6 is the diameter of the lens (which partly determines viewing field size), and the b usually is a designation denoting they're set-up for use with eyeglasses if you want.

Chujybear · Feb 9, 2015

So 40x6b is super zoomed in plus a tiny little hole to look through?

mitch · Feb 10, 2015

Chujybear said:
So 40x6b is super zoomed in plus a tiny little hole to look through?

kinda, yeah, but it's not so much a tiny hole to look thru as it is an optical compromise between magnification and aperture size/light gathering ability. some of it may be due to size limitations. in other words, maybe a 40x23b is possible, but would make for a huge ocular and probably be prohibitively expensive, too? just like a camera lens, the higher the zoom, the smaller the field, the more light is required, etc. maybe somebody who has more technical expertise in optics will chime in to explain this better than i can.

and what i meant by the "b" allowing for eyeglass usage is that your eye can be farther away from the lens surface without losing field size, either while wearing glasses or with the usual rubber cups & bare eyes. btw- my oculars are type b, but i never use them with my glasses.

KCSteve · Feb 10, 2015

6mm for the eyepiece aperature might seem small, but if it's larger than the pupil of your eye then the extra is just being wasted. A little bit more is ok - gives you some room for error as it were. Now the ratio of the aperature to the front optic is important - that's a limiter for how much light can come through.

Chujybear · Feb 10, 2015

Thanks.
Imagine the x40 will take a decent bite out of the working distance as well? Or do you keep the WD, but lose field of view, or depth of field?
G

mitch · Feb 11, 2015

Chujybear said:
Thanks.
Imagine the x40 will take a decent bite out of the working distance as well? Or do you keep the WD, but lose field of view, or depth of field?
G

yes, all three. look at pgs.4-6 of this Leica brochure for a complete rundown of various ocular & objective combinations, with corresponding working distances and field of view.
http://www.leica-microsystems.com/f... E/Brochures/Leica_StereoZoom_TechData_EN.pdf

Chujybear · Feb 11, 2015

Thanks Mitch. That covers pretty much any questions I could come up with.
G

mitch · Feb 11, 2015

you are most welcome.

40x6b

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