Sharp portrait

I've just read an article about shooting portraits by zooming in, locking, and then zooming out and taking photo.

Sounds correct to me but the article said that this technique is wrong with digital cameras / lens.

What are your thoughts on this?

I use a canon 20d with 17-85 lens

You mean locking focus? I would say 'bad' (digital or not) since the focus will change with focal length. Maybe it's 'digital focus'?- Terry

Sorry yes I mean locking focus and then zooming out.

What's the best technique then?

Focus (with centre point as this is the best for sharpness?) main feature (ie eyes) from distance I will be taking picture and then lower to get correct frame?

One of the overlooked reasons for multiple focus point is to us them as needed. Read this first: http://visual-vacations.com/Photogra...pose_sucks.htm

Learn to use your camera on the fly without having to stop and look at the button placement. Read page 64 and then 67 in the manual. If you don't have the manual go here. Pick the focus point you want that targets the area you most want in focus.

Be aware of the recompose problem, but it is generally exagerated as in the photo. If you really had the set up shown, you would either have a lens with a wide enough angle (short focal length) to easily include the 2 1/2 inches in focus or you are not taking pictures of her eyes anyway.

Also, at least on my camera, if I'm using a fast/shallow lens, my center focus point is much better than the rest.

Terry

If I am shooting sports I would agree, but with still subjects when shooting portraits any of the focus points works well.

Remember the optimal area in focus should be right at the point of focus. While the range of focus in a given DOF will look in focus it will gradually loose focus from that exact point of focus until it becomes noticeably out of focus.