Can I control the focal length?
我能控制焦距吗？
Set the focal length on your lens.
给你的镜头设置焦距。
Empty eyes, can not find the focal length.
空洞的眼眸，找不到焦距所在。
Focus: plane of focus; focal length; and depth of field.
焦距：焦点平面，焦距和景深。
That cone Angle is directly controlled by the focal length.
圆锥角度直接受到焦距的控制。
For me, one of the initial questions is how to set the focal length.
对于我来说，一个首要问题就是怎样设置焦距。
Focal length is the distance between optical centre and principal focus.
焦距就是镜片中心和焦点之间的距离。
Focal point is, the distance between the two is the focus of the focal length.
定点是焦点，两焦点的距离是焦距。
Focal length: The distance between the centre of a lens and its principal focus.
焦距：镜头中心与其主焦点的距离。
But once you have the focal length determined, everything else is a piece of cake.
但是，一旦你确定了焦距，其他事情就不值一提了。
But once you have the focal length determined, everything else is a piece of cake.
但是，一旦你确定了焦距，其他事情就不值一提了。
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