Sciencemadness Discussion Board

Quick question about microscope eyepieces

Doctor Cat - 3-7-2016 at 20:49

I want to buy these x30 eyepieces for my microscope on ebay:
My idea is to increase the augmentation limit of my current microscope (which is x1000 (oil) at the moment... So I have 2 question about this... Does it really work like this? I mean, if I change to a x30 eyepiece I will be able to zoom up to x3000 in oil...? if so, what are the major disadvantages of doing this?
My last question is about the eyepieces that I want to buy, are they good?

Thanks in advance!

Scalebar - 3-7-2016 at 23:56

You'll be up against the diffraction limit - the resolution of your 'scope doesn't depend on the power of the lens, it depends on the numerical aperture of the lens ( which should be written on the objective somewhere ), your resolution, theta is 1.22 times the wavelength divided by the numerical aperture practically speaking 1000x is the limit for a light microscope due to the whole wavelength thing.

Swapping out a 10x eyepiece for a 30x eyepiece will give you a bigger image but no better resolution - it's like holding a magnifying glass up to a computer screen.

FranklinNewhart - 8-2-2017 at 09:59

However using a 30 X eye piece with a 40 X aperture will give you 1200 power which is still pretty much at the limit but the nice thing is that now you don't have to use oil and you won't crash your lens into the slide which is really nice if you happen to not be using a cover slip.

Scalebar - 9-2-2017 at 00:38

Whether or not that's any use though will depend on the numerical aperture of the lens - a 40x air lens with a 30x eye piece may give you 1200 mag but it'll have an NA around 0.3 so will only resolve to 800nm, an oil lens at 40x will give you around 280nm.

The eye piece ultimately has no effect on resolving power - just on how big your blurry image is, a 10x eyepiece and a 10x lens will be nowhere near as effective as a 1x eyepiece and a 100x lens.