Note that it is very important to set the camera film back size correctly if focal length measurements in any units other than pixels are being entered.

请注意，这是非常重要的设置相机的胶片回来大小正确如果焦距测量在任何单位除了像素被进入。

youdao

Then, image surface position was kept steady during a zooming process by controlling the spherical aberration of front fixed group and the focal length of back fixed group.

之后，通过合理控制前固定组球差及后固定组焦距，使变焦过程中的像面保持稳定。

youdao