A photographer needs a lens with focal length of 0.2 m for close up shots. What is the power of the lens required ? How does a lens with higher power affect the focussing capability of a camera ?

Given,

Focal length = f = 0.2m

So,

$\text{P} = \dfrac{1}{\text{focal length (in metres)}} \\[1em] = \dfrac{1}{0.2} \\[1em] = \dfrac{10}{2} \\[1em] = 5 \space \text{D}$

A lens with higher power has a shorter focal length, allowing it to focus on nearby objects more effectively. This makes it ideal for close-up shots.