The ‘Optical Steady Shot’ (OSS) stabilisation worked like a dream on the A7 and although I did not test it to the limits, I have no doubt you are gaining 3 stops or so, which is typical. On the A7R, due to the mirror slap issue, OSS is switched off and cannot be activated, which is a nuisance. I shot almost entirely with the lens on the regular A7, so I could benefit from the OSS (as I shot almost everything handheld). Unfortunately, travelling with children does not allow tripod work, so what I shot tended to be opportunistic and very quickly executed (and often out of the car window!). I am quite confident my kids would have driven off in the rental car had I kept them waiting, so the OSS was a real boon. On one occasion I did shoot it on the A7 and A7R side by side and noted that even on a tripod, you really need to keep the A7R well above 1/200th to prevent vibration issues at the middle to long end. When shooting at 130mm or so, those shot at f5.6 and 1/400th were consistently a bit sharper than those at 1/250th and f7.1. Not by a huge amount, but if you are aiming to milk the most from the A7R sensor, it is a consideration and worth bearing in mind.
Just by way of context, the above frame will print at 200 dpi to 37″ or so, which gives a nice border on a 40″ piece of paper. It will look a lot tighter and more detailed at that size than it is appearing on screen at 100% above….
Conclusion? If you shoot in this focal range and are tempted by a native lens, I recommend you go for it. I used it far more than any other lens in Iceland, largely due to the nature of the landscape, but also the convenience and reliable IQ it offered. I have not seen a single soft frame, or frame lacking contrast. Everything looks like it should from a lens in this price range. Sure, the 55mm f1.8 prime is sharper, but that lens is sharper than everything else on the planet aside from a Zeiss Otus (and a couple of stops down there is nothing between them). The 35mm f2.8 FE is a little stronger too, but heck, these are expensive primes! Make no mistake: the Sony 70-200 F4 OSS delivers an extremely high quality of the file.
In comparing the A7 and A7R files, I am unlikely to bother shooting it on the A7R again, unless there is a particular need or reason. It performs so well on the A7 and it just seems the two are perfectly matched. The resolution difference is there (only when you are in the right shutter sped range), but its not that great and I’d perhaps only be tempted to switch the lens onto the A7R if I knew I was in the sweet spot of shutter speed, aperture and subject with lots of very fine detail and the intention to make a huge print. Otherwise, its just a lot easier to enjoy the handheld OSS benefits and sweeter shooting experience on the A7.
There are limits to the comparisons one can make with the Sony 28-70mm kit lens as they only overlap at the long end, but the 70-200 f4 OSS is in a completely different league. The kit lens’s files look vastly inferior.
Overall, this is probably the best overall lens in the line-up to date and an ideal companion to the A7, A7S and A7 II in particular. It just does everything right and has a flexibility the primes will never have. I only wish they had made it in black… Just note that if you do buy one, or any Sony or Sony Zeiss lens for that matter, I’d recommend only buying from a dealer that has a good return policy and won’t demand that you update your firmware if you complain of soft corners or edges on one side 😉 I wrote to Sony on this Quality Control issue and will write a short piece on it shortly!
P.S. Please bear in mind that my comments are not only based on shots seen here, but the classic planar brick wall test and many other frames. In the ‘real world’ you will notice all sorts of anomalies because subjects are not as planar as you think and depth of field is surprisingly thin with long lenses, even with distant subjects. This can result in you thinking, ‘oh, why is the bottom right not that sharp’ and the answer is that the bottom right is actually a lot closer to the camera that the bottom left, due to a subtle rise in the ground that you cannot recall or see in the image. Also note that a 30″ long image from the A7 is actually only a 50% magnification, which is half as demanding as these crops here and will be viewed from further away than your screen. Bottom line: perfect 30″ prints.
Uupdate January 2015: I used this lens very heavily in my first photography dedicated trip to Iceland, where it proved itself absolutely essential. You can see portfolios here and here and read more about how I got on with the Sony A7 and A7R under tough conditions, as well as the 70-200 f4 OSS and other lenses.