Raymond,
This is the stealth part of the appraisal business. The trick is never get caught or let the owner of the comp know you're around.
When I used 35mm film, I had a telephoto zoom lens for just that purpose-I could sit a block away and still shoot the home without the owner seeing me, if he was in the yard. My digital camera also has a zoom lens for the same purpose-just sit a block away and shoot the comp photo. Nobody is the wiser.
Of course, if you don't have a zoom lens, you could always learn the appraiser's trick-don't stop the car, don't slow down at all. Always shoot your comp photo as you come-up to the house or as you leave. Basically, don't shoot the photo as you go by the home because it will be a blurr. Try it sometime. As you drive toward the comp, the home will always be in focus and as you drive away and look back and it will be in focus. Works great for those homeowners who are in the yard-they just think you're passing traffic and they don't have a clue because the car never slows down. We all know that once you stop or slow down, all the neighborhood eyes focus on us......and as soon as the camera comes up to the window level, you're in trouble.
After I get the photo, I usually turn-around down the street and drive-by again to get the exterior description of the comp.
Another idea is to take whatever photo you can of the comp, place it in the report along with a nice clear copy of the MLS photo and state next to the lousy/blurry photo you took, something like "Owner in yard-clear comp photo not possible-see attached clear MLS photo." Works for me as we're not supposed to have anybody in the photos-it's that red lining thingee that the Feds frown upon. Since you've driven by the comps, your mission is complete for FHA/VA/FNMA/FHLMC. The comp photos are only for the underwriter to see if your mission was acceptable.
Remember, you can take a photo of anything you want as long as you're on public property (the street). The cops can't stop you nor can the property owner. They may grumble alot but too bad. My kids have the "My dad's an appraiser" answer down pat when the cops call my house looking for me because somebody complained about me taking a photo of their home and turned-in my license plate number. The cops just go away after that response-seems they know about us house photo "perverts."
Ben