A Photographer's Review of the Canon EOS 10D Digital SLR
Subject:   Depth of Field Button Double Duty
Date:   2003-04-01 21:29:23
From:   derrick
A feature I didn't mention in the article, but one I'm growing more fond of all the time is the "second use" for the depth of field button.

When you have the Canon 550 EX flash attached, or the ST-E2 wireless flash controller with any EX flash, press the depth of field button and th flash fires a series of flashes at 70Hz. It appears to the eye to be a steady light source. This serves an effective "modeling light" that allows you to preview your lighting setup. It's really nice.