I've been shying away from ISO's higher than 400. I'll take a stab at 800 now, however, because this is a wonderful shot. One of my favorite portrait lenses is a cheapy 50mm Canon prime, which is pretty fast, but the sun doesn't always cooperate. Wonderful shot!

You have very good models..

Beautifully composed and a beautiful model. Well done! DOF is excellent. I'm an amateur. I see your ISO was 800. Was that by choice? Just curious and trying to learn everything I can...

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Yes, I choose a high ISO to get to a faster shutter speed. My walk-about lens is the Canon 17-85 which stops down to f/5.6 at the maximum length, and this was very early on a cloudy morning. While I like this wonderfully diffused light that cloudy mornings give me, there's not much light to go around.

At that point, I think it's better to have a faster shutter speed and get a tack-sharp shot rather than a noise-free shot that has motion blur and becomes a session reject. With the 20D I don't notice much noise at ISO 800 anyway, so I use it when I need it. Now, I have the Sigma 28-70 f/2.8 which helps both my depth of field and my shutter speed on precisely these circumstances.

This picture can be summed up in one word. "Stunning". well done.