Getting sharp only through CDAF LiveView Shots with my D600 and 24-70 f2.8, why?

Started Jan 21, 2013 | Discussions thread
fad Forum Pro • Posts: 15,413
Terrible target

It's not only lack of contrast.   APS recently questioned some tests I did on a repaired 14-24 because I used Lens align.   The AF sensors are only sensitive to horizontal and vertical lines, and they consider even that target inappropriate.   So a diagonal line is basically invisible.  The AF sensors sees a featureless wall of uniform color.

So you have no contrast, and a diagonal line.  Your focus point was invisible to the sensors and bound to fail.

AF testing is so difficult -especially with zoom lenses --since it depends on geometry, contrast, quantity and quality of light, distance, focal length for zooms, stability of camera, aperture --I don't know if it does more harm than good for people like me.   If the lens is more than moderately out of alignment, it is probably better to get it calibrated.   If it is mildly out of alignment, it is hard to measure and irrelevant for most shooting situations.   --I know there are other views, but I've been following this and trying different methods, and I find it humbling.

The only lens I've had any suspicions about for my Nikons is the above-mentioned 14-24, which I actually broke in two pieces and APS has completely rebuilt.   I will send it back, and let them test it using their methods.   I get inconsistent results both using tests and on camera.   Maddening.

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All photos shot in downtown Manhattan unless otherwise noted.
Thanks in advance for the kindness of your comments or critiques.

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