Thick lenses

When light travels through a medium other than air, what is the real thickness of material (t) replaced by?

t’ = t/n

What is vertex power?

Vergence if light as it leaves the system

What is back and front vertex power?

• BVP → vergence if light leaving the second surface if the lens

• FVP → power of the vergence leaving the first surface if the lens

Work out the front and back vertex powers (BVP)

BVP

Work out the front no back vertex powers (fvp)

When we consider thin and thick lens, what Di we consider the surface powers?

• thin lens, nominal

• Thick lens, compensated

What is vertex power allowance (VPA) and what is the equation?

How much the surface must be amended by

• VPA = Compensated - Nominal

Find the base and cross curve

How do we find F2 for the base curve?

Now how do we get the cross curve?

Now try finding the base and cross curve for this question

Howe calculate F1?

How do we get the cross curve?

What is the accurate toric form for this question?