Being a pesky photographer, I have some experience on the matter. First of all, if anyone comes onto the construction site uninvited, get them to leave. They are potentially jeopardizing their safety and the safety of others.
But, sometimes work sites aren’t so private. People working in road construction perhaps best understand. There is no fence to separate their work site from the public gaze—just a few orange and black cones. And, people are curious and impressed by heavy equipment, so there is a lot of road work captured on camera.
But, sometimes you get someone who is doing more than snapping a few shots with their smartphone to show their friends. Sometimes, the person stays around the construction site for a while, they have professional camera equipment, and are keenly interested in your work.
If a person takes photos of you, your employees, or equipment working in public (from off-site), they have the right to to so. It is only if the photo gets published, could its use be deemed improper.
Improper use would be anything that casts your company in a negative or inaccurate manner or that infringes on a the privacy of a person appearing in the photo.
Contractors sometimes take out their smartphones and start taking pictures and/or video of me. I don’t know what they do with it. I sell a lot of my photos, usually with a story to trade publications and manufacturers. I want to say to them, “its not about you, I am writing a story on how to best mix your concrete, and you pouring concrete would make great art work for the story”.
I recommend approaching the photographer, and finding out what their intent is. Someone mistook me for someone investigating a complaint about their project. Once I told him that I am an equipment enthusiast and professional photographer, who has been on dozens of construction sites, he invited me back when a tunnel boring machine is scheduled to be on site.
If the photographer does plan on publishing the photos, find out where. Get their business card. See the photos when they get published. Make sure the photos don’t negatively depict your company or employees or infringe on their personal privacy.
Publication of a person’s photo without their consent could be an infringement of their privacy if the person is the subject of the photo, and not someone in the crowd of are peripheral to the scene or subject of the photo. Consider as well how well you can make out the face. Hard hats and tinted work glasses hide a lot.
Also find out where the photos are to be published because it could me a marketing opportunity to you. If it ends up on a photographer’s portfolio (https://www.flickr.com/photos/156383855@N04/) or trade media web site, it could mean an opportunity to bring more light to the project and your company via social media. If it ends up in print with a story, you may want to purchase advertising or offer a comment or try to shape the story.
This collection of photography is guaranteed not to infringe on anyone’s privacy; I call it “Construction from the Hips Down”: https://www.flickr.com/photos/156383855@N04/sets/72157687124815891