Objects close to the camera reproduce larger as compared to things further from the camera. Place the tennis ball on the floor at a measured distance from the camera. Make a series of pictures of the tennis ball at precisely measured distances.
View each image using a standardized setup. Measure the diameter of the image of the tennis ball using a precision meaning device. You can procure a 10 power loop with ridicule ruled with labeled circle diameters. Such a magnifier is available from a lithographic supply house or Edmonds Scientific. Make a chart of distance vs. image size. This will work if you standardized camera position and zoom and viewing conditions.

Objects close to the camera reproduce larger as compared to things further from the camera. Place the tennis ball on the floor at a measured distance from the camera. Make a series of pictures of the tennis ball at precisely measured distances.

View each image using a standardized setup. Measure the diameter of the image of the tennis ball using a precision meaning device. You can procure a 10-power loop with reticle ruled with labeled circle diameters. Such a magnifier is available from a lithographic supply house or Edmund Scientific.

Make a chart of distance vs. image size. This will work if you standardized camera position and zoom and viewing conditions.

Objects close to the camera reproduce larger as compared to things further from the camera. Place the tennis ball on the floor at a measured distance from the camera. Make a series of pictures of the tennis ball at precisely measured distances.
View each image using a standardized setup. Measure the diameter of the image of the tennis ball using a precision meaning device. You can procure a 10 power loop with ridicule ruled with labeled circle diameters. Such a magnifier is available from a lithographic supple house or Edmonds Scientific. Make a chart of distance vs. image size. This will work if you standardized camera position and zoom and viewing conditions.

Objects close to the camera reproduce larger as compared to things further from the camera. Place the tennis ball on the floor at a measured distance from the camera. Make a series of pictures of the tennis ball at precisely measured distances.
View each image using a standardized setup. Measure the diameter of the image of the tennis ball using a precision meaning device. You can procure a 10 power loop with ridicule ruled with labeled circle diameters. Such a magnifier is available from a lithographic supply house or Edmonds Scientific. Make a chart of distance vs. image size. This will work if you standardized camera position and zoom and viewing conditions.