UniCalc
RU
full version
Own formula
Calculation
Catalog
About
Help
Find a formula
Lenses
Determination of focal distance of lens
focal distance
f =
m
x
Å
nm
μm
mm
cm
dm
m
km
n mile
in
ft
yd
refractive index of material
n =
radius of curvature of more curved surface
r
1
=
m
x
Å
nm
μm
mm
cm
dm
m
km
n mile
in
ft
yd
radius of curvature of less curved surface
r
2
=
m
x
Å
nm
μm
mm
cm
dm
m
km
n mile
in
ft
yd
1. Define values of all variables, besides sought quantity
2. Change units if necessary
3. Click "Calculate"
