
488 APPENDIX G
Solution to Problem 4.1 (Continued)
zblind =
0.3927
echo off;
G.5 CHAPTER 5
Problem 5.1: Spherical Aberrations
Here we consider how the focus moves as we use larger parts of an aperture. The lens has a
focal length of 4 cm, and the object is located 100 cm in front of it. We may assume a thin lens
with a diameter of 2 cm.
5.1a What is the f -number of this lens?
Solution:
f
d
=
4
2
= 2. (G.37)
The lens is f/2.
5.1b Plot the location of the focus of rays passing through the lens at a height, h, from zero to
d/2, assuming the lens is biconvex.
5.1c Repeat assuming it is plano–convex.
5.1d Repeat assuming it is convex–plano.
5.1e Repeat for the optimal ...