What is meant by focal distance?
A. Think of focal distance as the distance the magnifier needs to be from the subject to be in focus. As magnification goes up, focal distance goes down. A 10x magnifier will have a very short focal distance, usually about one inch or less. In other words, the magnifier must be held one inch from the subject to properly focus. At such a short focal distance, there will not be much room for error. A fraction of an inch too close or too far will cause the magnifier to go out of focus. On the other hand, a large diameter, 2x magnifier will have a much greater focal distance, often as much as 5 inches. Furthermore, it will be much more forgiving as to the exact distance. For example, one can be off one or two inches either side of the listed focal length and still be in focus. However, you may not get maximum magnification or clarity when such distance errors are made. Magnifiers are designed to be used to magnify close up, not distant, objects. If you want to magnify your view of objects
