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<blockquote data-quote="J-see" data-source="post: 458307" data-attributes="member: 31330">The cam always does AF the lens at the widest aperture but by putting a TC between, you extend the lens and in that affect the shape of the light hitting the sensor(AF). That results into something similar as shooting at a different effective aperture, all negative effects included. Most cams automatically adjust the minimum aperture when connecting the TC. Mine directly switches to f/8 for the TC2.0.The speed of your AF depends on how wide the angle of light is. Which is why all fast lenses have massive front elements.Here's an image representing what an f/8 lens does and how it affects focus. The same happens by extending the lens when using TCs.[ATTACH]160417[/ATTACH]Here's the rest of the article on AF:<a href="http://www.clarkvision.com/articles/understanding.autofocus/" target="_blank">Understanding Autofocus, Clarkvision.com</a></blockquote>

[QUOTE="J-see, post: 458307, member: 31330"] The cam always does AF the lens at the widest aperture but by putting a TC between, you extend the lens and in that affect the shape of the light hitting the sensor(AF). That results into something similar as shooting at a different effective aperture, all negative effects included. Most cams automatically adjust the minimum aperture when connecting the TC. Mine directly switches to f/8 for the TC2.0. The speed of your AF depends on how wide the angle of light is. Which is why all fast lenses have massive front elements. Here's an image representing what an f/8 lens does and how it affects focus. The same happens by extending the lens when using TCs. [ATTACH=CONFIG]160417._xfImport[/ATTACH] Here's the rest of the article on AF: [url=http://www.clarkvision.com/articles/understanding.autofocus/]Understanding Autofocus, Clarkvision.com[/url] [/QUOTE]

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