Auto-focus on the A7 is compromised compared to any DSLR. I have a Sony a6000, which has much better AF-C than the A7 II, and the a6000 is still not as good as a K-3 for action, IME. K-3 AF is amazing in low light, the a6000's is pretty poor.
- Vario-Tessar® T* FE 24–70 mm F4 ZA OSS
- FE 70–200 mm F4 G OSS
What do you think those combos will do that a Pentax 16-50 and 50-135mm (or Sigma 17-50 and 50-150 f2.8) won't do? The extra stop on APS-C negates the FF noise advantage.
If you look at DXOMark, you will see that the A7S is only 1/3 of a stop ahead of more pixel-dense full-frame bodies. The new BSI FF sensor will likely match it for noise and will definitely murder it for resolution.
FF lens selection in E-mount is very limited, and most of the lenses that are available are expensive. Don't be taken in by the Zeiss mystique. Pentax lenses are pretty fine as well.
The difference in size is not so impressive either:
Compact Camera Meter Compact Camera Meter
Last edited by audiobomber; 06-29-2015 at 12:53 PM.