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>Hello all!
>
>I have used the latex beads inside the agarose 
>gel and I have measured the penetration depth of 
>NA: 1.2 60X lens about 600um,could it be wrong?
>
>Thanks
>Sarah

Dear Sara,

You don't say, but I believe that the (Nikon?) 
objective you describe is supposed to be used 
with a coverslip.

If you just use it just with agarose, two things 
will happen: You will have VERY high spherical 
aberration (and therefore z-direction 
measurements are not worth much) and, because the 
coverslip is missing, the working distance will 
appear to be more than the (about ) 200 µm that 
the lens was designed for.

Add a 170 µm coverslip on top of the agarose, and 
you should be able to see about 200 µm below the 
agarose/coverslip interface.

Cheers,

Jim P.
-- 
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Room 223, Zoology Research 
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3D Microscopy of Living Cells Course, June 14-26, 2008, UBC, Vancouver Canada
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