光學顯微鏡問題

Both the objective (物鏡) and eye-piece (目鏡) of a microscope are covex lenses with short focal lengths.
The magnification of a comound microscope can be calculated using the approximate equation below:
magnification m = (L/fo) x (D/fe)
where fo and fe are the ofcal lengths of the objective and eye-piece respectively
L is the length of the microscope tube (i.e. separation between objective and eye-piece)
D is the distance of distinct vision (normally taken to be 25 cm)

For derivation of the above equation, you may refer to the following web-page:

http://www.tutorvista.com/content/physics/physics-iv/optics/compound-microscope.php

You can see that m will increase if both fo and fe are small.

The above approximate equation is taken from the web-page below:
http://hyperphysics.phy-astr.gsu.edu/Hbase/geoopt/micros2.html