To keep the measurement light focusing on the measured surface, an automatic focus unit is very important.

要保证测量光聚焦在待测表面，自动聚焦控制是非常重要的。

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Previewing by red light, focusing by double red lights, and equipped with LED lighting.

单红光预览，双红光对焦，配备LED照明。

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"Some of these inventors have been designers of the human genome sequencer, incredible technologies around focusing sound in the same way have been able to focus light with lasers, health technologies like the stair-climbing wheelchair and a portable dialysis machine,".

VOA: standard.2009.12.18

The newly integrated Low Light AF enables accurate focusing on the subject even in low-lit situations.

ENGADGET: Panasonic Lumix GF6 announced for the US, shipping in June for $600

The key difference is that instead of focusing the light on a strip of photochemical film as in traditional cameras, digital cameras use an image sensor, called a charge coupled device (CCD), to capture the image.

FORBES: Technology briefing

Impressionists favor the clear light of midafternoon, and instead of focusing on panoramic views, they concentrate on the quality of natural light reflected on specific surfaces a single copse of trees, a short span of running river, a group of village houses and rooftops.

WSJ: Nature in America | A Landscape in Evolution | By Barrymore Laurence Scherer