Mudcat Café message #3983923 The Mudcat Café TM
Thread #165865   Message #3983923
Posted By: Mr Red
22-Mar-19 - 02:02 PM
Thread Name: BS: eyes - seeing things twice
Subject: RE: BS: eyes - seeing things twice
remember the Total Eclipse of the Sun?

The message was to shine sunlight through a pin hole on to white paper.

and early cameras were pin-hole.
Lenses use their whole width and rely on being the right shape, across their width. Pin-holes have precious little width. The eye is logarithmic in registering intensity, so with the reduced amount of light the retina gets is compensated by the retina/Optic nerve/brain. And we barely perceive a change in intensity. That's evolution for you.

The pupil changes diameter and visual acuity improves in brighter light because the pupil limits the amount of the lens used.