its all about the eyes

If there is one tip to give with portraits, it's that you you need to be careful when using a wide aperture settings.

Often the advice of friends and [some] websites is to half-press the shutter to focus on the eyes and then recompose the shot. If you have a wide aperture then the amount of image in focus can be so slim that recomposing the shot moves the focussed area off the eyes and you get a slight softening around the part you want.

If your equipment lets you, change the focussing point so that it is over the eyes as you frame the shot. This gives you a much better chance to keep the eyes (or whatever part of the image it is that you want) to remain in focus.
Read less