Pre-focus and difference in quality of the picture

[shc89]

First of all hello to everyone. I just bought a Sony DSC-W80 and started to explore it's abilities. One of the thing is the pre-focus option when you press the button half-way down before you shoot an image. I understand it's good when you want to eliminate the shutter lag and take a picture instantly, but is there a difference in quality of the picture when you press it first half way down and when you press it to shoot straight away? Is there any difference in the way the camera takes a picture which could make quality of the picture vary ? Thank you.

 

[rexter]

If your camera is capable of focus tracking or same terms technology, means if you subject is moving while you press the botton half way then it does help on focusing and proper exposure. I don't think there's difference in pictures, becuase the camera is set to takes the shoots fast to minize blur unless set manually on some digital P&S.