…and we’ve all been shooting on Auto this whole time.

Man can change his pupil size on command, once thought an impossible feat

By Yasemin Saplakoglu

For those who maybe don’t totally get this joke, a cameras aperture and the human iris work in a very similar manor. The larger the aperture opening, the more light is allowed to expose the film or sensor and the shallower the depth of field.

In a bright area, stare at your hand about 1 foot away from your face. Lock your eyes on your hand and observe how blurry your peripheral vision is. Next, try to dim the lights and stare at your hand. Again, 1 foot away, you should notice that it is much blurrier then before. It has to do with how your eye adjusts to allow light, by opening the iris. For more on how aperture works, check out (This Post).