| 1. | A typical lens has a focal length(f)of 625 mm .
常见镜头的焦距（f）为625毫米。 |
| 2. | The focal depth was about 6 mi .
震源深度约6哩。 |
| 3. | As a result, the focal lengths in these planes will be different .
结果，这两个平面内的焦距将不同。 |
| 4. | The focal length of a given lens is different for different colors .
一个特定的透镜的焦距因颜色的不同而不同。 |
| 5. | The baker super-schmidt camera can operate with extremely low focal ratios .
Baker超施密特照相机则能以非常低的焦比工作。 |
| 6. | The focal length of the camera lens plays an important role in photo criteria .
摄影机镜头的焦距在摄影规范中起着重要的作用。 |
| 7. | The field of view can be limited by inserting a stop in the focal plane of microscope .
可以在显微镜的焦平面上加装一光阑，从而限制视区。 |
| 8. | The unsteadiness of air becomes prohibitive only if instruments with large focal length are used .
只有在使用长焦距的仪器时，才不允许空气的不稳定。 |
| 9. | The mirror of an astronomical telescope forms at its focal point an image of a star on the axis of the mirror .
天文望远镜把在镜轴上的星体成象在焦点上。 |
| 10. | The focal length of the conelensing lens should be such that the image of the source just fills the projecting lens .
聚光透镜的焦距应使光源的像正好照满放映透镜。 |
