There are (at least) 3 times you should avoid using auto focus on a surveillance.
1. Shooting video through windows.
Now, if you are shooting video through a window, you better have a darn good reason! Most of the time that’s treading on what the subject might consider their “reasonable expectation of privacy”. Plus, it’s super creepy.
Of course you’ll frequently be shooting surveillance video through your own car or van window. If that’s the case you can use auto focus, but beware of rain or snow on your window because a camera shooting in auto focus mode may focus in on the rain drops and blur out your subject!
2. Shooting video through chain link fence.
Your camera can easily focus onto the fence and blur out everything on the other side of the fence. ‘Nuff said.
3. Low light conditions.
It’s inadvisable to use auto focus in low light conditions. Auto focus just wont reliably focus on your subject. Even if auto focus does somehow manage to capture what you want, passing headlights, a cell phone screen, lighting a cigarette or any light source can easily throw off the focus.
Let me know if you have any questions about this or ideas that might help other P.I.’s.
Committed to your success on surveillance,
Larry Kaye, P.I.
P.S. – Don’t miss my special report titled… If You Want To be a Private Investigator Give Up… Unless You Do These Three Things. You can get it on the home page of my blog.