In practice, there are a couple of ways to handle this. In one case, EXIF data gives you a lot of information (sensor size, camera/drone make, etc.) that you can extract very good camera intrinsics from. This information can also be fed into big EXIF databases, from which you can obtain pretty accurate camera parameters.

Additionally, camera intrinsic calibration is a relatively solved problem, especially if you know that every single camera has the same intrinsics.