I know a few guys who said they had to butt their cigarette out or pull their pants up after watering a tree to shoot a deer. But then I've also seen deer smell my tracks from 3 hours earlier and instantly bolt the other way. I've also seen them stare at me, pound the ground, peek around trees and never run until the second the wind shifts and they catch scent.
I still try to err on the side of no human scent, but sometimes I think no matter what you do, breathing included, they will react differently in any given situation. One thing is certain, they have an incredible sense of smell.
As for pics, I have the camera set to take a picture every 15 seconds. I find the bucks come in, and are gone within 1 minute usually the last pic it is staring at the camera and gone. It is an IR camera and makes a very quiet low pitched click when a picture is taken. The does will come right up to the camera, say hi and stick around for 15-20 minutes posing for the camera.
Here's few of the locals over the last couple of days....