The short version: Sony's compact, full-frame, mirror-less, interchangeable lens camera body, with a respectable kit lens, produces wonderful photos. Its performance isn't always quite on par with similar DSLRs and doesn't have many dedicated lenses available, but it is smaller and priced more competitively. It can also make use of a broad range of legacy lenses from other camera systems, making it quite versatile.
The long version: The Sony a7 is the lightest and smallest full-frame sensor, mirror-less, interchangeable lens, digital camera currently made. It is a first, and as such, has some growing pains. But on the whole, it is an amazing, fairly compact camera system -- with a full-frame sensor! You get DSLR-like performance with this more compact package in most instances. Aside from improved overall responsiveness (speed between shots and focusing) and image quality, what this means for the uninitiated is that you'll get a much shallower depth of field, especially when the subject is close and the aperture is low (open). This is ideal for portraiture and creates very pleasing bokeh (out of focus background elements). The a7 produces much less noisy images than compact digicams in low-light conditions as well.
Camera aficionados and photography experts are more likely to know what they are getting when they choose this camera and may be reading these reviews just to see what other user's experiences have been. I'm preface this review by saying this is my first full frame DSLR style camera. I've been shooting with SLRs since the 80s and have owned a wide range of digital bridge and point-and-shoot cameras (including other Sonys), but never stepped up to a digital model -- though I have used them. I recently purchased a Fujifilm X-S1 12MP EXR, and aside from the longer range of its fixed lens and some aspects unique to it, and I have to say that the a7K surpasses it in almost every other aspect. The menu system here is a bit more complex than on point-and-shoot models, but a power user wants that in a nearly $2k full-frame body. I'm sure that there is better glass out there, but I find the provided 28-70mm kit lens quite good. As it now stands, there is a limited selection of lenses made for / optimized to this camera (4 currently), so if you want maximum flexibility, you would probably want to go with a full-frame Nikon or Cannon body. They will be significantly larger though, not mirror-less, and likely more expensive. Also, with adaptors, the Sony a7 can make use of any number of legacy lenses you might have laying around from your film SLR days. You will have some cropping issues, but this is a wonderful option to have.
The a7 has a TON of neat features and options I could comment on, but will try to be brief and speak to the basics. I will likely revisit this review after further use, and when I have the opportunity to use it with different lenses. So from the perspective of a first time DSLR user, here are my likes and dislikes:
* Exceptional image quality. The 24MP CMOS sensor is fantastic and produces good JPEG images and even better RAW files. * Exceptional build quality. This camera is solid in the hand and has some weatherproofing. * Respectable kit lens for the cost, though I wish it had a bit more zoom. * Top-notch HD movie capture in a variety of formats and quality options. Built-in microphone and headphone ports. * Great ergonomics. The a7 is a pleasure to use. Yes, there is shutter noise, but there is something very satisfying about that 'click' when you snap off a shot. * Extensive customization options. I've still not fully explored every setting this camera has to offer. Auto mode will produce good photos, but the a7 shines when you customize the settings. * Very responsive. While startup times vary and previous DSLR users may find them tad slow, focusing, shot-to-shot and read times are impressive (with a fast SDHC card - I recommend the SanDisk Extreme 64 GB SDXC). This may not be the ideal camera for a dedicated sports photographer, but I've had good luck shooting my daughter's night soccer games. The focusing system is superior to that of the a7R. * Bright, hi-res, 3" tilting LCD. I wish it swung side to side as well, but it still adds flexibility when shooting. The a7 also offers a very accurate on-screen electronic level. * The 100% coverage, 2.4M dot OLED is what I prefer for shooting. It's an amazing digital viewfinder and is proximity activated. * In camera battery charging. Some may complain that the a7 doesn't come with an external charger, but considering the price of the camera, getting a 3rd party external charger with 2 extra batteries is quite affordable (and recommended - mine is the Wasabi Power Battery (2-Pack) and Charger). * 24.3 MP resolution. That's enough pixels to allow for cropping and high quality print images. A low enough pixel count to make the most of the sensor, work well in low-light, and not have (overly) unwieldy file sizes. I prefer this to the 36.4 MP of the a7R. * Cool Sony mode options such as Panorama and HDR, just to name a couple. * Wi-Fi and smartphone connectivity. * The option to use any number of lenses made for other camera with the purchase of the proper adapter.
* No built-in flash. * Lack of lenses built to make the most of the a7's sensor. As of this writing, there are only 4, but more are promised soon. Sony E-Mount lenses are compatible, but there is some cropping. * The multi-level menus can be a bit complex until you are really familiar with this camera. * Autofocus is usually accurate and fast, but not always and less so in low light. * I've found battery life to be decent, but not on par with similar DSLRs. You want to have backups for a full day of shooting. * With the provided 28-70mm kit lens, it's not ideal for macro photography. * It took me a while to get iPhoto to recognize the camera when attached so that I could directly download photos. You'll need to play with you connection settings in the menus.
Who isn't this camera for? Those looking for a pocketable camera, folks on a tight budget, serious sports photographers, or previous full-frame DSLR users expecting the same quality and speed that they are used to in this compact body.
I'm really enjoying using the Sony a7. It looks, feels and acts the part of a high-end, well designed, quality modern camera. As a person who has primarily used bridge cameras and smaller digicams over the course of his digital career, I'm quite happy with the manual focus kit lens Sony provides. I wish the 28-70mm lens was slightly faster and had a little longer reach, but given the a7's 24.3 MP sensor, I can crop a bit if need be. It has thus far been very versatile, performing admirably for portraiture, landscapes, sports and close-up photography. Video too! It will be months before I've fully explored all that the a7 with this lens has to offer, but I can safely say than for it's performance, form factor, flexibility and cost, it is the best camera I've yet to own. As I mentioned before, two items you may want to immediately purchase with this camera are a fast and large memory card, and additional batteries with a charger. Both of those items set me back under $100. A camera bag to hold your equipment is a good investment as well. For the a7, a good budget option is the Evecase Universal Black/Grey Large DSLR Camera Travel Case/Bag with Strap. For those looking to use 3rd party lenses with the a7, keep in mind the added cost of the adapters.
I'm giving the a7 +4 for it's minor imperfections, but I really do love it, so perhaps should have given it +5. For the sake of objectivity and quick reference, I'll stick with 4. However, I have a hard time imagining anyone who has only used fixed lens digicams up to this point not loving this camera and the photos and video it produces. More demanding photographers may feel differently, but good luck finding a new full-frame body AND kit lens anywhere else at this price.