Busting the Lens dictates Focus Speed Myth

Started Mar 22, 2013 | Discussions thread
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WilbaW
WilbaW Forum Pro • Posts: 10,762
Re: Busting the Lens dictates Focus Speed Myth

meland wrote:

The maximum aperture of the lens - a wider maximum aperture will let more light through for the AF system to do it's measurement.

(Assuming you're not just talking about the f/2.8 threshold that switches between the standard and high precision AF sensors...) No, the AF sensors don't see the scene like the image sensor does. Think of the image sensor as seeing the brightness in the room, and the AF sensors as telescopes looking through a window. If you open the curtains the room gets brighter but images through the telescopes don't get brighter.

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