Remove delay to aquire webcam frames in realtime

I am working on a program to track faces in real time. I am using the snapshot() function to get RGB frames for processing, however there always appears to be a 1 second or greater delay from the time I use snapshot() function to when the output can be displayed. I saw using the preview() function there is no such delay.

My question is, can I either speed up the snapshot() function to remove the delay, or process the information from the preview() function to get an RGB frame from it? I am also open to any other functions that could accomplish this task.

Thanks for any and all help.