Am I within my right to take pictures of canvassers/salespersons who come to my front door without their permission?

My concern is that criminals may pose as salespersons to try to get a feel for when my home would be a good target for theft. I have developed a habit of taking a photo/video of salespersons who come to my door. My hope is that by knowing their photo has been taken, they will avoid my property/neighborhood if they have nefarious intentions. I recently had a salesperson object to having their picture taken, and I told him that I have every right to photograph anyone on my property. I told him he should stay off my property if he didn't want me to take his photo.