focal-length

基本解释

At present, some difficulties are encountered in measurement of long focal-length of mirrors.
目前，大口径长焦距反射镜焦距的精确测量存在很大难题。
One zoom lens can replace several fixed focal-length lensed, but results are likely to be inferior.
一个变焦镜头可以代替多个固定焦矩镜头，但效果很可能比不上。
Using a group of mirrors and a housing that's almost big enough to use as a coffin, Canon was able to stretch the focal-length on this SLR-specific lens to 5,150mm.
佳能的这款单反相机专用折反镜头采用了一组折反镜片，以及一个跟棺材差不多大的镜身，其焦距被拓展到5150mm。

Featuring a powerful high-magnification optical 26X super-telephoto zoom lens, the new PENTAX X-5 provides photographers with a focal length of 4mm-104mm (22.3mm ultra-wide angle to 580mm super telephoto 35mm equivalent).
ENGADGET: Pentax intros X-5 superzoom camera with 26x lens, tiltable LCD
The high-end Schneider lens offers a 24mm, ultra-wide focal length and 3x optical zoom.
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TL34HD boasts an impressive resolution of 14.7 megapixels and renowned Schneider lens yielding a 28mm wide-angle focal length with 3.6x optical zoom.
ENGADGET: Samsung gets official with 14.7MP TL34HD point-and-shoot

the distance from the focal point of a lens or mirror to the reflecting surface of the mirror or the centre point of the lens

焦距
A new method of measuring telephoto lens focal length is presented in this paper.
提出一种新的测量长焦透镜焦距的方法。
焦长度
焦长

焦距
Using Gradual Aberration optimization Method, a 6m focal length, 600mm aperture off-axis aspherical optical system is successfully aligned.
采用像差逐项优化法,成功地装调了焦距为6m 口径600 mm 的离轴三反镜光学系统。
焦点距离
焦