AF Question for A99
Given the identical goals behind the AF-D and AF-C modes, it would have been convenient if Sony had merged this with the AF-C function, having the camera using the 102 focus-assist points automatically if a compatible lens were attached. Maybe in the next camera.
It works identically to “AF-C” mode, the only difference being that once it achieves focus using the standard phase-detect array, it will then use the 102 supplemental focus points baked into the sensor while attempting to track the moving subject. This feature is greyed out unless you have a compatible lens attached (the list of compatible lenses was presented back in in Chapter 1, starting on page 25).
From the Friedman book
By Spring 2013, Sony plans to provide a firmware update so these lenses will work too: Planar T* 85mm F1.4 ZA, Sonnar T* 135mm F1.8 ZA, 70- 300mm F4.5-5.6 G SSM, 70-200mm F2.8 G, 100mm F2.8 Macro, 300mm F2.8 G.
Right now this feature works only with a limited selection of lenses (which will expand with future firmware updates). Which lenses will it work with? Right now: Vario-Sonnar T* 24-70mm F2.8 ZA SSM, 50mm F1.4, 28- 75mm F2.8 SAM, 70-400mm F4-5.6 G SSM, 500mm F4 G SSM, 300mm F2.8 G II (New lens).