Big Number Cruncher

A whopping 42.4MP at a blazing12fps! And there are more numbers under the hood of the Sony Alpha 99II, as K Madhavan Pillai discovers.

- K Madhavan Pillai

Sony has been known to pull rabbits out of its hat. With the success of its mirrorless fullframe E-mount A7 series, speculations were rife if this signalled the end for Sony’s fullframe A-mount DSLT cameras. Firstly, Sony really does not have a fullframe DSLT line-up to speak of. There was just the A99, released about four years ago, the predecessor to which was the A900 (Sony’s very first fullframe DSLR). Secondly, it couldn’t be easy to develop and support four lines of lenses— the A and E-mount families for fullframe and APS-C sensor cameras. The launch of the A99II not only comes as a relief for anyone who invested in A-mount lenses, but is also sure to find a whole new set of first time users who are enamoured by its sheer range of features.

Features

At the heart of the A99II is a newly designed 42.4MP back-illuminated CMOS sensor that not only has an improved light gathering capability (ISO 100 to 25,600 by default, and ISO 50 to 1,02,400 with expansion), but also incorporates 399 on-sensor Phase Detect AF (PDAF) points. To maximise pixel level sharpness, this sensor has no optical low pass filter.

The translucent mirror of this DSLT allows the redirection of a small percentage of the total light received (about half a stop worth) from the lens to a separate, dedicated PDAF sensor with an additional 79 points some of which intersect with the points on the main imaging sensor for a Hybrid Cross Type AF system with extreme levels of accuracy. Put together, these AF points cover almost the entire imaging area of the sensor.