Q1: Some opera glasses are said to be good for viewing sports and theater. Some are only for theater. What is the difference?

A: Some opera glasses have their optics permanently set on optimal focus ranges for indoor theater productions. Others have a center-focus apparatus that will give infinite variability in viewing range. Then, too, there are the matters of field of view and magnification. It's difficult to watch sporting events with glasses that have a very narrow field of view; it's hard to follo the action. Low-power opera glasses also are not very useful in large stadiums, where one might be several hundred yards from the action or at a race track where the action may take place a half-mile away.