Capturing the Essence of an Amaryllis

Depth of field refers to how much of your subject is in sharp focus, and this is an easy thing to control on your shots, once you learn the exposure triangle (covered in another post.) Aperture is expressed as a fraction, so f2.4 is actually1/2.4. F11 would then be 1/11. The low numbers (F1.2, F2.4) actually let you have less in focus or less depth of field and the higher numbers (F8, F11, F16) allow you to have more in focus. Shooting in aperture priority (Av on Canon) allows you to control the focus, provided your subject is stable. You can clearly see the diffence on these shots.

The first one is with the lens stopped down to a small aperture (F11). Virtually all of the flower is in sharp focus.

The second shot is with a wide open aperture (F2.4) so the petals of the amaryllis are in much softer focus. Not even all the anthers are in sharp focus, because they are not all on the same plane.

This gives you creative control over your shots. Do you want a sharply rendered subject, or do you want softer focus on the back portions? The first photo is more of an accurate rendering of the amaryllis bloom, while the second photo gives a dreamy look to the flower. Try it on a stable subject under even light to test this out, and let us know what you prefer.