C
Converging Lens
i L
Di
Divergent Lens
tL
Lens Maker’s Equation
Note that this assumes that the lens is placed in air. Otherwise, replace n with the ratio of the refractive indices
Combinations of Lenses
1. Follow the lens equation to calculate the image position for lens #1 alone (as if lens #2 is not there). 1
1
1


p1 q1
f1
2. From q1 and the separation of the lenses, one can figure out the proper value of p2 for lens #2 then follow the lens equation to calculate the image position #2
for lens #2 then follow the lens equation to calculate the image position #2. 1
1
1


p2 q2
f2
Keys: If p2 ends up to be behind lens #2, you need to use the negative value.
Image formed by refraction at a spherical surface
n1 n2 n2  n1
 
p q
R