how much light reaches that sensor. There are three controls. Aperture. Think of it as the

pupil in your eye. Large opening, more light, blurred background, lower f-number, f2, 1.8.

Small opening, less light, more of the scene in focus, higher f-number, f8, f11. Example,

portrait of Anna, f2, blurred background. Landscape, f8, everything sharp. Your iPhone's

aperture is fixed on each lens, so you don't control this directly. The Canon will let you.

Shutter speed, how long the camera looks at the scene. Fast shutter, freezes motion, less light.

Examples, 1,000 sec, 1,000 sec. Slow shutter, motion blur, more light. Examples, 1,30 sec,

1 sec. Think a moving van outside TLC Foods. 1,000 sec, frozen, 1,15 sec, blurred.

ISO, this is sensor sensitivity. Low ISO,

cleaner image, less noise. High ISO, brighter image, more grain noise.