I have 2 D800s and unfortunately they only work in studio....

Started Jan 12, 2013 | Discussions thread
TOF guy
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Re: PDAF and Aberration Correction
In reply to SteveL54, Jan 15, 2013

Actually the light source (color temp) can make a difference with phase detect AF. The imaging lenses are typically corrected as achromats, but I don't believe the small optics in the PDAF unit are that well corrected, so some firmware correction for color may need to be applied.

A canon marketing brochure on there PDAF mentions this. See the lower left hand side of page 4. (Auto focus accuracy under all lighting conditions thanks to light-source detection)

http://www.canon.co.uk/Images/EOS%201DMKIV%20Technology%20Feature%20Guide_tcm14-721276.pdf

Thank you for that reading. I stand corrected. It is required to correct for the color of the light source.

Of course whether Nikon does this is speculation. Any of the older RGB sensors would be able to apply a target color correction term. This doesn't require 90K RGB sensor.

This would explain why some D800 seems to misfocus badly under tungsten light: there is a sensor, there is a correction applied ... and some D800 are badly miscalibrated for this correction.

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Thierry - posted as regular forum member

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