How to use a focimeter

1. Measure the focal length of the lens: First, place the lens to be measured on the platform of the focimeter. Then, adjust the focimeter's holder so that it is level with the lens. By adjusting the eyepiece on the focimeter, align it with the center of the lens to be tested. Next, adjust the moving platform on the focimeter so that the eyepiece is aligned with a clear field of view. Finally, read the value on the eyepiece scale, which is the focal length of the lens.
2. Measure the focal length of the lens: Similarly, place the lens to be measured on the platform of the focimeter, and adjust the bracket and moving platform of the focimeter so that they are level with the lens and aligned with the center of the lens. Adjust the lens against the eyepiece on the focimeter so that it lines up with a clear field of view. Finally, read the value on the eyepiece scale, which is the focal length of the lens.
3. Measure the focal length of a convex and concave mirror: for a convex mirror, place the convex surface toward the eyepiece; for a concave mirror, place the concave surface toward the eyepiece. Then measure as above.
It should be noted that during the measurement process, ensure that the lens or lens maintains good contact with the focimeter platform to avoid errors. In addition, when reading the eyepiece scale, observe carefully and record the value accurately to ensure the accuracy of the measurement results.