Optimum Aperture

How do we achieve the optimum aperture?

By stopping down the lens to minimise the effects of aberrations whilst ensuring that we do not reduce the resolving power of the lens due to the effects of difraction.

 

Further reading look up 'Diffraction Limited Optics'

Ex1.

i. Explain the effect of Difraction in your own words and simple sketches

ii.Give examples of equipment that use DLO's