Review: Sony Alpha SLT-A77
With the release of the Sony Alpha SLT-A55 and SLT-A33 in late 2010, Sony created a new category of camera, similar to a conventional digital SLR in many respects (same sensor size, lens mounts, general form factor) but with an ingenious technical twist in the way it uses the camera’s internal mirror. The A55 and A33 were bleeding-edge products whose novelty was impressive enough to overshadow some of their usability shortcomings. With the release of the Alpha SLT-A77, however, Sony has almost fully realized the promise of the earlier cameras. The 24-megapixel, 12-frames-per-second SLT-A77 is a grown-up, ready-to-work, 21st-century machine.
Resolution and noise
As noted in the Macworld review of the Sony Alpha SLT-A55, the new Sony SLT (single-lens translucent) cameras use a fixed translucent or “pellicle” mirror that lets most of the light coming through the lens go straight to the sensor, while also continuously bouncing a little of the light up to an ultrafast phase-detect autofocus sensor.
The SLT design does mean a little less light reaches the imaging sensor than in a conventional SLR. Sony says the light loss is about half a stop. That sounds like a lot, but as a practical matter, it isn’t. To compensate for the loss of light that the fixed translucent mirror causes, Sony increased the gain on the sensor slightly; that is, it made the sensor a little more sensitive.
The downside of this new technology, as Macworld’s testing verifies, is that the A77 is a little noisier than DSLR counterparts such as the Nikon D7000 or Canon 7D, especially above ISO 1600.
For the past couple of years, as sensor manufacturers such as Sony made it possible to take quite usable photos at ISOs that were unthinkable not long ago, high-ISO, low-light performance has become a bit of an obsession with enthusiasts—and reviewers. This is unfortunate. Great photos want great light, and always will. In any case, there’s more to a great camera than how noisy its images are at ISO 3200.
A more practical indicator of image quality is the image viewed at its normal screen resolution, or even better, as a well-made print. And in that respect, the unprecedented 24-megapixel resolution of the A77's APS-C CMOS sensor works to offset the slight increase in noise. The A77’s 6000-by-4000-pixel images provide detail to spare for breathtakingly crisp prints, even at 13 by 19 inches. Cropped images from the A77 look fantastic too, both on the iPad’s 2048-by-1536-pixel Retina display and on my 21.5-inch iMac’s HD (1920-by-1080-pixel) screen.
It is worth noting that the A77 applies noise reduction in-camera to JPEGs at higher ISOs; you can adjust the level but not turn it off altogether. Keep in mind that noise reduction (in-camera or on the computer) inevitably results in some loss of fine detail. My recommendation is to set High ISO noise reduction to Low in the camera's menus. For critical work, your best bet is to shoot raw and deal with the noise on your computer.
Another innovation in Sony’s SLT cameras is the replacement of the conventional optical viewfinder with an electronic viewfinder (EVF). This remains the A77’s most controversial feature. Early EVFs, common in compact cameras, tended to be horrid little things, but the technology has been improving—and with the A77, Sony has made a major leap forward. The EVF in the A77 is a half-inch-wide OLED screen with 2.3 million dots, showing 100 percent of the capture area at 1.1 percent magnification. Those are pro camera viewfinder specs. The first thing I noticed when I put the A77’s finder to my eye is that it was bigger, brighter, and sharper than I expected. I think I actually said, “Wow!”
In most situations, in terms of image clarity and color accuracy, the A77’s ultrahigh-resolution EVF provides a result that is, if not better than that of an optical viewfinder, at least close enough that most of the time I forget I’m looking at a digital display screen. The key to the EVF’s success is the OLED technology and the incredible resolution of the electronic viewfinder. There is just one situation that the EVF still struggles with: high-contrast scenes with both very bright areas and very dark areas. But optical viewfinders don’t do so well in all lighting conditions, either (for example, near darkness).
The A77's EVF also brings with it a few special advantages. The most obvious one is that the exposure you see is the exposure you will get, or very close to it. Shooting in M mode with a conventional camera, you can easily spoil a shot by failing to notice the little ‘-2.0’ exposure value warning in your finder. But on an A77, you wouldn’t fail to notice that the scene you’re viewing in the finder is really dark. Even in one of the automatic modes—say, Program or Aperture Priority—if you want to dial in some exposure compensation, you don’t have to guess and take shots. Using the A77, you just press the +/- button, move the gauge a little, and see the results instantly.
In addition to live, accurate exposure information, the EVF provides an overlay with useful information: a small histogram, a level, and more. I find the EVF terrifically useful, and I miss it when I work with one of my older optical-viewfinder DSLRs.
The A77 also has a state-of-the-art live-view LCD monitor.
The camera activates the EVF and turns off the LCD when your eye gets close to the viewfinder, then turns off the EVF (to save battery power) and activates the LCD when you take your eye away from the camera. This autosensing system works nicely most of the time, but it can be fooled: Occasionally the LCD went dark when I brought the camera too close to my face or my chest.
The LCD tilts and swivels, and spins around. You can even fold it up and turn it around so that you can look at it while you try to take a self-portrait.
I use manual focus a lot, and the A77 provides a couple of terrific aids: focus magnification and focus peaking. Focus magnification blows up an area of the scene, such as the subject’s eyes; I fine-tune the focus, and then take the picture. But I’m using the alternative, focus peaking, more and more. When this feature is enabled, the edges of whatever I’m shooting that are in sharpest focus are highlighted in a color of my choice. Manual focus on the Sony A77 is easier to use and more accurate than it has ever been on any camera I've used before.
That creates a bit of a dilemma, because one of the big benefits of the SLT system is that it makes full-time phase-detect autofocus (PDAF) available, and the A77’s phase-detect autofocus, relying as it does on 19 autofocus points (11 cross-type), is generally about as precise as manual focus, and much faster. Unless I point the camera at something that has zero contrast, the camera almost always focuses the instant I press the shutter halfway. In very low light—in fact, even in complete darkness—the A77 focuses quickly and accurately, due to an autofocus assist lamp that throws a patterned highlight on the subject. Continuous PDAF works pretty well on moving objects, even while shooting video, but the camera doesn’t always track moving objects quite as tenaciously as the Nikon D7000 does. Moreover, the face-detection feature in the A77 is so good that I’m rethinking manual focus for portraits altogether. I’m getting soft.
It’s not magic, it’s electronics
The elimination of the moving mirror provides the A77 with several performance benefits, including a maximum burst rate of 12 frames per second, which is crazy fast, or a more rational but still-impressive 8 fps. Unfortunately, you can’t shoot at those speeds for long before the camera’s buffer gets full. I tried using high-speed shooting at a rodeo, thinking I’d maximize my chance of getting just the right frame when the rider landed on his face. As often as not, the rider stayed on the bronco half a second too long, and I missed the shot entirely. Generally I keep the shutter set to a dignified 3-fps continuous shooting, and I seldom miss a shot.
The A77's speedy exposure rate makes possible certain other features in which the camera takes many shots almost at once, including multiframe noise reduction (MFNR) and a special in-camera HDR feature. MFNR, the more useful of the two, is a setting in the ISO menu that prompts the camera to take multiple images, almost simultaneously, and then meld them into a single, less noisy image. I’m not yet convinced that this approach is better than making a single raw capture and applying noise reduction judiciously on the computer; doing it yourself with a raw file lets you strike your own best compromise between reducing noise and preserving fine detail. But using the MFNR feature is a lot easier than playing with sliders in Aperture or Lightroom.
The A77, like most other Sony cameras now, includes a sweep-panorama feature that relies heavily on the powerful Bionz processor but also benefits from the camera’s ultrahigh-speed shutter.
The A77 provides a competitive set of video features, notably the ability to use continuous phase-detect autofocus while recording. Alternatively you maintain full control over other exposure settings such as aperture, but in this case you’ll have to focus manually. Difficult trade-offs!
The A77 offers two basic video formats (AVCHD and MP4), a wide variety of capture resolutions and speeds (including true 60-fps 1920 by 1080 in AVCHD), a stereo mic (mono speaker), and more. I stick with the slower and lower-res MP4 because the files work on the Mac OS with a minimum of fuss, and for the family videos that I take, the quality is excellent.
As good as the A77’s video is, it can’t do something the Sony RX100 compact camera can: capture a high-res still image while shooting video.
Lenses and metering
Sony sells the A77 body only and in a couple of body-plus-lens packages. I recommend buying the body with the DT 16-50 f/2.8 SSM lens (totaling about $1899). This is not the usual so-so kit lens. It is a superior-quality lens that retails for $800 by itself; buy the camera with the lens, and you’ll save a couple hundred dollars. The 16-50 lens is an outstanding complement to the A77 for two reasons. First, the A77’s 24-megapixel sensor is wasted on a mediocre lens. Second, the A77 is (as of October 2012) Sony’s only weather-resistant body, and the 16-50 f/2.8 was until very recently the company's only weather-resistant lens. The A77 has excellent in-body image stabilization, so you have no need for costly lens-based stabilization.
As you’d expect from a camera this expensive, you can fine-tune autofocus on your lenses if you determine that a given lens has front or back focus issues with your camera. With the 16-50 and now about a dozen other lenses, the A77’s Bionz processor can correct for various optical foibles as you shoot, but only if you are writing JPEGs. I’m still shooting raw—and, when necessary, fixing such problems by hand in Lightroom—but here again, I’m starting to wonder if I’m not working too hard.
In general the camera’s auto-exposure system works very well, with a tendency (as on many other cameras) to underexpose to avoid blowing highlights.
Like most cameras in this price range, the A77 puts as many controls as possible on the outside of the body rather than burying them in the menu. And it has a lot of these external controls, with nine pushable buttons (including the joystick and the movie button) on the right rear of the body alone. Since I don’t use the Display button often, I wish that it were back in the upper-left corner, where it is on the A580. And, although a top LCD has long been de rigueur on high-end cameras, it seems a waste of space on the A77, since the EVF and the rear LCD provide so much info.
But those are minor gripes. Overall, the A77 handles very well. Manual-mode photographers will particularly appreciate the presence of both front and rear control dials. When you do have to get into the menus, you'll find that they're single-paged, logically organized, and easy to navigate. But this is where you’ll want to pull out the user manual: The menus have lots of options.
The biggest of my few serious complaints about the A77 is the lack of control you have in instant review. For instance, when I want to check to see whether a subject blinked, I find it annoying that I can’t control the initial magnification of an image I'm reviewing or the steps by which magnification increases or decreases.
Battery life and more
Battery life for the A77 is about 500 still photos taken during “normal” shooting; that's okay for casual photographers, but if you’re shooting a wedding, you’ll want to pack a couple of spares. The A77 has built-in GPS for geotagging your photos. Using GPS reduces battery life, but I love this feature and keep it on most of the time.
The A77 has a built-in flash. It’s decent, as built-in flashes go; what I like most about it is that it can serve as a triggering device for an off-camera Sony flash such as the HVL-F42AM unit.
One caveat for Mac users: If you need to upgrade the firmware on your A77 (as I did), you won’t be able to do it from a computer running Mountain Lion, because the Sony firmware updater is 32-bit only, and Mountain Lion can’t boot into 32-bit mode as older versions of the Mac OS can. I used my daughter’s MacBook, which is still running OS X 10.5. Sony should do what Pentax does, and allow you to download the firmware, copy it to an SD Card, and perform the firmware update right in the camera.
With an OLED electronic viewfinder of unprecedented size and clarity, plus a variety of other advanced features, the Sony Alpha SLT-A77 brings the technical promise of the earlier Sony SLTs to fulfillment. With its arsenal of novel whiz-bang features, the A77 is a lot of fun to shoot with. But make no mistake—this is a camera for serious photographers. I’ll add a warning, too, and note that the A77 can be a bit unforgiving: Perhaps it’s the high resolution, but with the A77, I’ve felt that I had to step up my game.
Original photos by William Porter. All rights reserved.
- High-res OLED EVF provides ultrasharp view with WYSIWYG exposure feedback
- Superfast 12-fps shooting; excellent range of options for video capture
- Focus magnification and/or focus peaking for manual focus
- EVF struggles a bit in very high-contrast scenes
- Noisier images than some competing cameras when shooting in low light at higher ISOs
- Default magnification for instant review not user-configurable