Here is the problem I've been trying to solve for a couple of weeks. I have taken 2 pictures of an object of an unknown size with a camera. The first picture of the object was 1162 pixels across. I moved 419.1 mm closer and took a second picture, which was 1429 pixels across. Can I calculate the size of the object in mm? What if I had a table of radians per pixel at different distances, could you deduce the distance from that? Focal length: 3.85mm Aperture: f/2.8 Shutter: 1/15 Resolution: 2048 x 1536 Let me know if you want some test data to test your calculations.