What is the meaning of saying " the plwer of lens is 1 dioptre"?

Question

What is the meaning of saying " the plwer of lens is 1 dioptre"?

1 Answer

Impact of this question

1948 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-06-21T13:27:11

A lens is more powerful as the focal length decreases.

Explanation:

This was thought contra-intuitive, to have a smaller number for a stronger lens. So they created a new measure: the diopter, or 'power' of a lens is defined as the inverse of the focal length, or:

$D = \frac{1}{f}$ $D=1/f$ with $f$ $f$ in meters, or $D = \frac{1000}{f}$ $D=1000/f$ with $f$ $f$ in millimeters.

The reverse is also true: $f = \frac{1}{D}$ $f=1/D$ or $f = \frac{1000}{D}$ $f=1000/D$ , depending on the use of meters or mm.

So a lens with a 'power'of 1 Diopter has a focal length of:

$f = \frac{1}{1} = 1 m$ $f=1/1=1m$ or $f = \frac{1000}{1} = 1000 m m$ $f=1000/1=1000mm$

A standard $50 m m$ $50 mm$ camera lens will have a 'power' of:

$D = \frac{1000}{50} = 20$ $D=1000/50=20$ diopter.

Science

Math

Humanities

... and beyond

What is the meaning of saying " the plwer of lens is 1 dioptre"?

1 Answer

Explanation:

Related questions

Impact of this question