DxOMark just published their ranking of the Sony Alpha A6600. This compact 24 megapixels Mirrorless Digital Camera is currently the APS-C flagship in the Sony lineup. Its 24 MP High-Speed CMOS sensor is mounted on a capable 5-axis image-stabilization system effective to 5-stops over hand-holding. The sensor itself features a 425-Point Phase-Detect AF system built-in. Combined with high-speed readout, this lets the Sony Alpha A6600 offer realtime eye-tracking AF. As one expected from a flagship camera, this one features dual control-dials and a builtin EVF with Eye-Start Sensor in a weatherproof body.
Analysis of image-quality from the A6600 sensor gives it a DxOMark ranking of 82. This is a very good performance firmly within the range of the best APS-C cameras on the market. While this score falls shy of best-in-class, it the A6600 delivers really well on most fronts. Currently, the highest DxOMark ranking of an APS-C digital camera is the Nikon D7200, a 5-year-old 24 MP DSLR. Clearly, technological improvements have improving image-quality much slower than before. It’s a completely different story for different aspects such as speed but those are not relevant to the DxOMark ranking.
The Nikon D7200 reviewed here get a DxOMark of 87, while the best Sony APS-C mirrorless get a score for the Alpha A6500 and A6300 which are tied at 85. Those two cameras share the same 24 MP APS-C CMOS sensor with the A6500 adding stabilization, which only the A6600 also offers, among Sony APS-C mirrorless. Most modern DSLRs perform closely with the entry-level D3400 pulling a score of 86. Only 3 points lower, the A6600 gets the same rank as the 8-year-old Pentax K-5 IIs reviewed here, still among the best performing DSLR of all times. Many cameras from 2012-2014 perform around this level, showing that there are physical limits for this sensor-size.
DxOMark scoring is made of 3 constituents that combine with as a weighted average. Each component though is more relevant to a certain type of photography, which is why it is often more important to look deeply into the breakdown. The first component is bit-depth which measure color-precision (NOTE: this is different from color-accuracy). The bit-depth component of the A6600 is a respectable 23.8 bits-per-pixel. Although this particular score pulls this camera down overall, its impact is extremely difficult to notice.
The second component is Dynamic-Range which measures the amount of contrast in a scene that can be captured by a single exposure of the camera. Here, the Sony Alpha A6600 manages 13.4 EV which is actually a major setback for this sensor-size. The most dynamic-range an APS-C camera can capture is 14.6 EV, again achieved by the D7200. This exceptional DSLR is an entire half-stop better than its nearest competitor, the Pentax K-5 IIs which scores 14.1 EV. Theoretically, dynamic-range is limited mostly be sensor-size yet all APS-C cameras that capture over 14-stops are 4 to 8 years old! This suggests that additional circuitry to make these sensors faster and add Phase-Detect is causing an increase in noise-floor.
Where the new Sony Alpha A6600 delivers a best-in-class performance is in the third Sports component. This is a measure of High-ISO performance which the A6600 clocks at 1497, surpassing the D7500 DSLR and Sony A6xxx series by a small margin. The implication is that high sensitivities show less noise than any other APS-C camera.
Overall, this is very good rating for the Sony A6600 which remains one of the optimally-balanced mirrorless cameras on the market by its combination of quality, feature and size. This confirms the dominance of APS-C over smaller sensors when it comes to image-quality, while also showing that true image-quality improvement is only available on Full-Frame and Medium Format cameras which are all larger and heavier, plus those need correspondingly larger and heavier lenses.