After a few small photo tours I want to share my experience. For E-Mount spoiled photographer it is only once a huge piston at the camera. Front it is wide, especially if the sun visor is fitted. But it is worth it to drag the part? In my opinion, yes.
Especially in difficult lighting conditions, it has already shown what it can. In backlight hardly reflections are in the lens, the image is still konstrastreich. Especially with ultra wide angle you often light sources in the image. Even otherwise the contrast is high and the resolution good. As we know from Zeiss, black areas are black, are hardly outshone by stray light. The best conditions for vivid colors.
Minimal spongy it is in the corners at 16 mm, even with smaller apertures. But this is criticism on very high level, in other ultra-wide angle lenses I have experienced significantly more weakness in the corners. From the image section the image at 16 mm is roughly comparable to the 10 mm of SEL1018 on APS-C (10 mm * 1.5 = 15 mm).
However, I would like to mention that by the often strained focal length conversion applies only to the shot, but not for the perspective distortion. 16 mm 16 mm, whether to APS-C or full-frame, only the picture detail is greater. The advantage of 16 mm at full frame compared to 10 mm for APS-C is therefore the less perspective distortion with the same image.
All in all, this lens the high demands of full-frame sensors justice. It is the absolutely necessary complement to the Sony Zeiss 24-70mm toward ultra wide angle. If one does not work with third-party, where ever there is nothing to this objective is the quality solution. Apart from a fixed focal length (what?) You will get away with hardly less and less weight.
From Sony 10-18 mm, in my opinion one of the best lenses for APS-C, I was spoiled by the stabilizer. Before, I thought you'd need at wide angle or even ultra-wide no stabilizer. Now I know him appreciate even there and did not want to do without it. That was in the end decisive with me zuzulegen something more important and higher-priced lens.
Conclusion: If you want the most optimal solution for E-mount full-frame and do not mind the price, get a lot offered here. Otherwise, there are also many quality alternatives.