How to Take Still-Life Photographs Using Your Digital SLR
Adjust your camera settings.
You want a shallow depth of field to draw attention to the still life, so use Aperture Priority mode and an aperture with an f/stop between f/4 for a small grouping or a single flower and f/7.1 for lots of flowers in a big vase. If you have nice light coming in, your ISO setting should be 200; go up to 400 as needed. A focal range of 85mm to 150mm lets you keep some distance or zoom in. Choose Single Shot drive and focus modes and turn on image stabilization if you have it.