| 摘要 |
<p>A focussing mechanism for a telescope or pair of binoculars uses a spring (1) which can be controlled by the operator whilst holding the glasses with both hands. The instrument is lightly pressed against the eyes or released so that the spring causes the distance between the eyepiece section (3) and the lens section (7) to alter and so change the focus. A fixing screw (8) may be provided to lock the position at any preset-focus, or to act as a precision focussing adjustment.</p> |
