Always use manual focus, auto doesn't work worth a darn. Used P mode which is pretty much auto in RAW for these couple of shots.

just what it's supposed to do: works just barely good enough for most people, most of the time. You, however, are a using a specialized macro lens to photograph a 4-6mm unrestrained wild animal at life-size magnification from 12 inches away. (ain't no Easy-Shooting mode for that!)

So along with focus accuracy, you must have precise control over depth-of-field, which you will have if you switch to Av mode and set the aperture size manually. If you are using flash, set the camera for Manual exposure, f/11 to f/16, and shutter speed at 1/200s.

Baby Phid. That shot was certainly not in anything above f/11. I use only manual focus and manual on the camera setting so I can push the F stop up to f/16 or higher for these tiny girls if I can get it. This will not be possible without a flash however. Or a nice tripod maneuver. These small alert spiders are some of the most difficult camera subjects even when you have them in a smaller controlled capture environment. Hard not to love 'em though.