what is thin lense
A piece of optically transparent material,
bound with two polished surfaces, at least
one of which is curved.’
what do conVEX enses do
- is a converging surface
- has positive power
- increases the vergence of light
Convex and concave
surfaces
what do conCAVE lenses do
- is a diverging surface
- has negative power
- reduces the vergence of light
Convex and concave
surfaces
difference between F1 and F2 equations
f1 is n’1-1/r while f2 is 1-n’/r
F total equation
F1+F2
PARAXIAL RAY EQUATION ORDER
F then L then L’ then l’
whats the circle of least confusion
blur circle between the 2 focal lines which have been formed
formula for least confusion
L1+L2/2
what should you do for a Corneal Astigmatism
do (f90=n’n/r90) - (f180=n’-n/r180)
what are the 2 types of astigmatism
Corneal astigmatism
Lenticular astigmatism
what causes a corneal astigmatism
when the 2 radius’s of the cornea F180 and F90 have different values
what causes a lenticular astigmatism
Toroidal surfaces, or a tilted lens
