I know there are a lot of Sony a7 family reviews out there and I wasnt going to add another one to internet's junk yard. But I'm going to review quite a bit of gear for a7R in the next few month and it seems necessary to establish my own opinion about the camera prior to that...
a7R body is made from good quality scratch-resistant materials. It's a mix of magnesium alloy and some polymers. All are precision cut and fit very well together. The camera has a nice hefty feel to it, it feels like a quality product that can take some beating and continue functioning. I have had it for couple of months now and taken it on multiple flights and trips, and so far not a single scratch.
The screen is probably the most breakable part. The covers of I/O ports are pretty flimsy as well, I can see these getting damaged over time if you use them a lot. Luckily I do not.
Other than that, there is not much bad to be said about a7R's build quality. I have used it in light rain and it is certainly weather resistant. I have read a review that claims it is as resistant as 5DmIII. Maybe so, but I probably wouldn't trust it as much as the Canon in rain.
Also, about the build differences between a7 and a7R. I had a chance to shoot a bit with a7 and I don't feel that there is much difference in build quality. The controls feel similar although the materials are different. The front body cover is plastic, but a good quality one and feels just as sturdy as a7R's magnesium one. I would say that the difference in build quality alone shouldn't play a role in your decision between the two models.
Design and Controls
I know it is very personal, but I really like the design of Sony a7 cameras. And not just aesthetically, also the controls and menus design.
The body borrows its lines from the classic SLRs and rangefinders, like electronic viewfinder (EVF) being hidden inside pentaprism-shaped bulge or camera body having rangefinder boxiness to it. Nevertheless, a7R still looks like a modern camera. Unlike Nikon Df it doesn't look retro - it borrows some elements from vintage cameras, but still looks modern and unique.
Control dials on top of the camera have great machined finish to them, grippy patterns on each dial are designed in a slightly different way. Those are tiny details, but they add to the quality of the product.
Moulded grip is good, eventhough it feels a bit small in my large hands it doesn't feel like a toy camera and my fingers still manage to reach all the controls. It is a bit awkward to press the C1 button, but you get used to it and it becomes more natural.
I read some folks complain about all the controls being clustered on the right hand side. Personally, I think it was a great design decision by Sony. Once you get used to the controls you can reach all of them with the right hand, without looking away from the viewfinder, and your left hand is free to operate the zoom and the focus on the lens. This is especially handy if you favour using manual focus.
The menu is very simple to understand, and with the ability to program all the controls to your liking there is rarely a reason to go into the menu. The default control setup is so good that you don't need to make many changes to it. I did change the Fn button options significantly to suit my needs, but outside of that the only controls I have set differently were Down on the directional control wheel and C3. I have left everything else as it comes out of the box and I am very happy with it.
I'm not a huge fan of the way Sony implemented the articulated screen. It is nice to be able to tilt the screen and I use it occasionally, but I also found myself wishing that the screen would tilt along both axis. However, I use the viewfinder so much more. It's bright and detailed and much better for manual focusing than the screen. So the lack of the 2-axis tilt is not a huge issue.
Another part of the camera I don't like is the factory strap. It's thin and synthetic.
I think a7 and a7R success is a testimony not just to the fact that the market is ready for mirrorless full frame, but also that despite minor nuisances these cameras are pretty well designed. The folks at Sony should be very proud of the work they've done.
Image Quality and Functionality
Let me state it outright - I am not going to bore you with technical data and lots of 100% crops. I don't think at this point a7 and a7R need yet another review telling you how good the image quality is and how they stack up against Nikon D800 or Pentax 645D. Everyone knows both Sonys deliver outstanding image quality, if you are after best pixel-level performance - DXOmark will tell you everything you need to know.
I'd rather talk about which of the two is the better choice, a7 or a7R. My guess that most people, me including, struggle to make the decision between the two. So I'll try to give you my rational behind choosing a7R over a7. I'll try to be as objective as possible.
First lets get out of the way all the identical features.
Coming from 7D I was really surprised how good a7R's auto white balance is. It is not always spot on, but it is usually pretty close, I rarely have to adjust it.
Dynamic Range Optimiser (DRO)
This setting automatically brightens darker areas of the image and darkens any areas being blown out. It has six levels of intensity including auto level.
From comparing shots taken with and without DRO I am fairly certain that it doesn't reduce image quality so you can always leave it on. In terms of effectiveness, I would say it gives you an extra .3 f-stops of dynamic range, at most. Mostly you see the difference in highlights and shadows. It has less affect on the blacks and practically none on the blown out whites. I always leave it on Auto. I used to have it under the Fn menu, but now I removed it and never touch it.
It works only when shooting JPEGs. If you are serious about HDR you will use bracketing and process HDR shots in Photoshop or another software.
A lot has been said about ISO performance of both cameras. I have read claims that sway both ways, that one's ISO performance is better than the other's. I trust DXOmark sensor scoring and according to it a7R's sensor has somewhat better ISO performance.
From my tests, I don't see a noticeable difference between the two cameras. Both perform exceptionally well up to 1600. At 3200 and 6400 there is a noticeable reduction in image quality, but it is still acceptable. Just for reference, I shot mostly in aperture priority with auto ISO and I have set auto ISO max value to 3200.
Zebra (overexposure alert)
Nice to have, but distracts from the subject - I keep it off.
Manual Focus Assist
Awesome! I use it a lot with manual lenses.
Manual Focus Peaking
Another handy feature for manual focusing. Not accurate enough for precision work, but after some time getting used to it you learn to compensate for its inaccuracies.
Poor in both cameras.
Alright, those out of the way lets compare a7 to a7R. There are three key different between the two cameras - all three have something to do with the sensor.
a7 packs 24mpix sensor with anti-aliasing filter, and contrast- and phase-detection focus elements, while a7R packs 36mpix sensor without anti-aliasing filter, and only contrast-detection focus elements.
So which one is better? Which one should you get?
I don't think there is one answer. It depends on what you shoot, how you shoot, what lenses you use etc. I'll try to break it down and use my own decisions for a perspective.
24MP vs 36MP
Looking purely at image quality, as much as I want to say that 36MP is better, I have to admit that the differences between the two are negligible. You can notice the difference under careful examination of 100% crops, but unless you want to make large prints you will never be looking at 100% magnification outside of post-processing workflow.
Where the 36MP sensor does make a difference is when you crop. Extra 12MP gives you a bit more room for cropping while keeping the detail just as high. I'm not a proponent of heavy cropping, if you take a photo you better frame it right from the start, but cropping definitely helps in some situations. For example, one of my ultra-wide options for a7R is Voigtlander 15mm f4.5 VM. I will talk about it separately, but sometimes I like to crop photos shot with this lens down to 16mm, 17mm or even 21mm. That's when the extra 12MP come very handy. 15mm shot cropped down to 21mm is about 24MP, if I shoot it on a7 it would get cropped down to 16MP.
Contrast- VS phase-detection auto-focus
This camera made me a better photographer. Using manual primes I spend more time thinking about the framing. It forces you to be more involved than simply pointing and shooting. I focus much faster manually nowadays, much faster than I used to. Sony FE 55 f1.8 is my only auto-focus lens, but even with that lens I barely use auto-focus, for me the lack of phase-detect is not an issue at all.
I played with a7 a bit, after getting a7R. I do find that phase-detect is faster, but usually not as accurate - maybe a hair off. It tends to miss focus more frequently and by a larger margin. Also, in low light phase-detect can seek a lot while contrast-detect would snap into focus.
The difference in focus between the two camera models is pretty insubstantial, don't listen to folks complaining about a7R's auto-focus - it's exaggerated. But if you intend on using only native lenses and rely mostly on auto-focus I would recommend to get the a7. You'll be able to get the body and one lens for the price of a7R body. For me personally a7R made more sense because from the get go I was planning to use manual primes.
This is a tricky one. In theory, removal of anti-aliasing filter should result in slightly sharper photos. In reality, we don't have a 36MP sensor with the filter to compare the results to (and please don't say “what about Nikon D800?” that camera has different brains). What the absence of the filter does affect is the magnitude of colour cast affects when using wide angle rangefinder lenses a7R produces slightly weaker colour casts than a7. I'll talk more about the colour casts and wide angle options in the Lens section.
Also, absence of AA filter is know to cause moire. Honestly, I occasionally notice moire in my photos, but it is rare and barely noticeable. In the photo below you can see moire pattern on the panels , but this is something that doesn't happen very often.
Image quality of both a7 models is fantastic, your decision shouldn't be affected by the pixel count and should be based on how you intend to use the camera. If you are going to use a lot of rangefinder or vintage glass, or if you like to crop your shots frequently - get a7R. If you intend to stick to Sony FE lenses - save yourself some money and get the a7.
Most importantly, whichever you pick I promise you - you won't be disappointed. And if you are - then you would be with either models.
I forgot to mention one more difference - a7R has a very loud shutter. Abnoxiously so. But a7 is not quiet like a mouse either. If you are after a quite camera maybe Sony a7 family is not for you.