Sony's A33 uses new translucent mirror technology in a digital camera for the first time. Is this the beginning of the end for DSLR cameras as we know them? That What Digital Camera Sony Alpha A33 review...
Preview based on a pre-production SLT-A77 running firmware 0.65
Visit http://www.dpreview.com/previews/sonyslta77/ for full priview
After a four-year wait, Sony has returned to the enthusiast/semi-pro end of the DSLR market. Having made little impact in that market with the A700 that very closely resembled the conventional DSLRs made by Canon and Nikon, Sony has spent the intervening time developing something a bit different. The A77 builds on the company's 'translucent mirror' technology, and uses an electronic rather than optical viewfinder. The final result is a product that may look traditional, but is able to promise the unconventional.
Spec-wise the A77 is impressive: it features a new 24MP APS-C CMOS sensor, 12fps full-resolution shooting and the highest resolution EVF we've ever encountered (a 2.4M dot OLED finder). It also uses a new 19-point AF sensor, 11 points of which are cross-type (sensitive to detail in both the vertical and horizontal axis). Clever use of the main sensor's live view allows the A77 to track objects as they move across the frame, enabling the camera to have a better understanding of which AF point it should be using at any given time.
Last year's SLT-A55 gave some clues about how Sony hoped to bring its electronics know-how to bear in a high-end camera. Its fixed, semi-transparent mirror design meant Sony could do away with a conventional optical viewfinder and use an electronic display. It also meant that the phase-detection autofocus that gives DSLRs much of their immediacy could be used all the time. The result was a camera that could shoot at an impressive 10fps, could focus quickly in video mode and offered full-time live view with consistent DSLR-like behaviour in a way that no camera had really managed before.
Unsurprisingly the A77 takes all these capabilities a lot further than the consumer-level A55 - it combines the latest processor with an electronic first curtain shutter to offer the level of responsiveness the more demanding enthusiast/semi-pro users will expect. The A77's massively improved viewfinder is also key to ensuring the A77 can hold its own against the very stiff competition it faces from the likes of Canon's 7D. (You don't have to read particularly far between the lines to conclude it was this feature Sony wanted to perfect before launching an SLT into this market.)
And, as with the A55 and a handful of other recent Sony cameras, the A77 offers in-camera GPS. It can be a really useful feature for organising and retreiving images, as allowing tagged images to be geo-located on sites such as Flickr. As with all GPS settings, it can take a while to locate enough satellites, or struggle to find them at all in built-up areas. Then, of course, there's a battery penalty to be paid.
In addition to the technological advances, Sony has clearly been listening to its audience when developing the camera's firmware - the A77 is not just the most customizable Sony we've ever encountered, but that customization includes a number of long asked-for features. In addition to the ability to fine-adjust the AF tuning, Sony has added the ability to define the upper and lower extremes that the Auto ISO system will use - a step we suspect many users will welcome.
But despite all this technological wizardry, the A77 is actually a remarkably conventional-feeling camera. It may have a plastic top-plate, rather than the A700's tank-like magnesium-alloy construction, and use SD rather than CF cards, but in pretty much every other respect it looks and behaves like a logical progression of the series. Overall, despite the fact that it embraces a rather different set of technologies, it feels and behaves much like a conventional semi-pro DSLR.
Sony SLT-A77 key specifications:
- 24MP CMOS Sensor
- 12fps continuous shooting with autofocus
- 1080p60 movies with autofocus
- 2.4M dot OLED viewfinder
- 1/8000th maximum shutter speed, shutter rated for 150,000 actuations
- ISO 100 - 16,000 (25,600 with multi-image combination. Expands down to ISO 50)
- Auto ISO with customisable lower and upper limits
- Optional, profile-based correction of vignetting, chromatic aberrations and geometric distortion
- Pull-out three-hinge tilt/swivel 920k dot LCD screen
- Built-in GPS
- Top panel LCD
- Stereo microphone and external mic socket
- AF Micro Adjust
- Dust shake sensor cleaning
First impressions
The OLED 'TruFinder' appears to have been the key technological barrier Sony felt it needed to overcome to offer an SLT camera at this level. It's certainly very impressive and more than a match for the pentamirror style finders that the A65 will find itself up against. The difference is less pronounced at the A77 level, where the competition feature 100% field-of-view pentaprism finders. It is considerably larger than even those finders, though, and the ability for the preview to more closely resemble the output image can be a real bonus.
One situation in which the EVF loses out to an optical finder is if it's used in bright light with glasses, where there is a much greater difference in intensity between the ambient light and the light coming from the finder. In this particular situation we found ourselves having to cup a hand around the viewfinder. The fact that this, rather niche, case was the only time we found our attention drawn to the viewfinder technology says a lot about how impressive it is.
Of course there will be some A700 owners (some of whom will have been keeping the faith since the Konica Minolta days) who will be apprehensive about joining up for Sony's SLT adventure but, having spent some time with one, we'd suggest they find a way to spend some time with one before jumping to conclusions. You may not think you want a camera with an EVF but our first impressions are that, in use, you may quickly find you're enjoying the camera too much to care.
Beyond this, probably the most positive thing you can say about the A77 is that (even if you're a tech-aware camera reviewer), you rarely find yourself thinking about the technologies or their implementation: you just use the camera and think about how its capabilities can aid your next shot. The A55 did a great job of making live view feel like a seamless part of the shooting experience - the A77 builds on this to provide an A700-like sense that all the tools you need are close-to-hand, so that you can concentrate on your photography, not the camera.
SLT-A77 and A65 key differences
 Sony SLT-A77 |  Sony SLT-65 | |
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| Sensor | 24MP APS-C CMOS | 24MP APS-C CMOS |
| Body construction | Magnesium Alloy/Plastic | Plastic |
| Control dials | 2 | 1 |
| Maximum shooting rate | 12fps | 10fps |
| Auto ISO | Customizable upper and lower limits | Fixed at 100-1600 |
| Viewfinder | 2.4M dot OLED TruFinder | 2.4M dot OLED TruFinder |
| AF Sensor | 19 points (11 cross-type) | 15 points (3 cross-type) |
| AF fine-tune | Yes | No |
| Joystick controller | Yes | No |
| Top LCD panel | Yes | No |
| Flash sync socket | Yes | No |
| LCD Articulation | Triple hinged (hinge/tilt/swivel) | Double-hinged (tilt/swivel) |
| Video | 1080p60 AVCHD 2.0 | 1080p60 AVCHD 2.0 |
| Flash sync speed | 1/250th | 1/160th |
| Maximum shutter speed | 1/8000th | 1/4000th |
Samples Galleries
There are 50 images in the samples gallery. Please do not reproduce any of these images on a website or any newsletter / magazine without prior permission (see our copyright page). We make the originals available for private users to download to their own machines for personal examination or printing (in conjunction with this review), we do so in good faith, please don't abuse it.Unless otherwise noted images taken with no particular settings at full resolution. Because our review images are now hosted on the 'galleries' section of dpreview.com, you can enjoy all of the new galleries functionality when browsing these samples. The links on this page will go straight to a slideshow.
The images quality should be considered pre-production, but from a camera that Sony has advised is representative of final quality. We suggest that conclusions regarding image quality be drawn from our full review
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| Sony Alpha SLT-A77 Preview Samples |
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Sony SLT-A77specifications
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| Price (Body only) (with 16-50mm F2.8) | • US: $1399 • US: $1999 |
| Body material | Magnesium alloy and high-grade plastic exterior |
| Sensor | • APS-C "Exmor" HD CMOS • 23.5 x 15.6 mm • 24.7 million total pixels • 24.3 million effective pixels • RGB (Primary) color filter array |
| Anti-dust system | Charge protection coating on low-pass filter and Image Sensor-Shift mechanism |
| Image sizes | • 6000 x 4000 (3:2) • 4240 x 2832 (3:2) • 3008 x 2000 (3:2) • 6000 x 3376 (16:9) • 4240 x 2400 (16:9) • 3008 x 1688 (16:9) |
| Sweep Panorama | • Wide: horizontal 12416 x 1856 (23M), vertical 5536 x 2160 (12M) • Standard: horizontal 8192 x 1856 (15M), vertical 3872 x 2160 (8.4M) |
| 3D Sweep Panorama | • Wide: 7152 x 1080 (7.7M) • Standard: 4912 x 1080 (5.3M) • 16:9: 1920 x 1080 (2.1M) |
| Image sizes (Video) | NTSC: • AVCHD: 1920 x 1080 (60p/ 28Mbps/ PS, 60i/ 24Mbps/ FX, 60i/ 17Mbps/ FH, 24p/ 24Mbps/ FX, 24p/ 17Mbps/ FH) • MP4: 1440 x 1080 (30fps/ 12Mbps), VGA: 640 x 480 (30fps/ 3Mbps) PAL: • 1920 x 1080 (50p/ 28Mbps/ PS, 50i/ 24Mbps/ FX, 50i/ 17Mbps/ FH, 25p/ 24Mbps/ FX, 25p/ 17Mbps/ FH) • MP4: 1440 x 1080 (25fps/ 12M), VGA: 640 x 480 (25fps/ 3M) |
| Aspect ratios | • 3:2 • 16:9 • Variable (Sweep Panorama & 3D Sweep Panorama) |
| File formats | • RAW • RAW + JPEG • JPEG - Standard • JPEG - Fine • JPEG - Extra Fine |
| File formats (Movie) | • AVCHD 2.0 (Progressive) / MP4 • MPEG-4 AVC (H.264) |
| Lenses | • Sony A-mount • Konica-Minolta AF mount |
| Focus modes | • Auto Focus (19-point phase-detection AF system) • Manual focus • Direct Manual Focus, • Face Detection • AF Tracking |
| AF modes | • Single-shot AF (AF-S) • Continuous AF (AF-C) • Automatic AF (AF-A) selectable |
| AF assist lamp | Yes, dedicated lamp |
| Image stabilization | SteadyShot INSIDE |
| Exposure modes | • Program AE • Aperture priority AE • Shutter priority AE • Manual • Auto • Auto + • High-speed mode (10-fps) • Sweep Panorama 3D • Sweep Panorama • SCN (see below) • Continuous Advance Priority AE |
| Scene modes | • Portrait • Sports Action • Macro • Landscape • Sunset • Night view • Hand held Twilight • Night portrait |
| Picture Effect | • Posterization (Color, B/W), • Pop Color • Retro Photo • Partial Color (R,G,B,Y) • High Contrast Monochrome • Toy Camera • Soft High-key • Soft Focus • HDR Painting • Rich-tone Monochrome • Miniature |
| Sensitivity | • Auto • ISO 100 • ISO 200 • ISO 400 • ISO 800 • ISO 1600 • ISO 3200 • ISO 6400 • ISO 12800 • ISO 16000 • ISO 25600 (multi-shot NR mode - JPEG only) |
| ISO steps | 1/3 or 1.0 EV |
| Metering range | -2 to 17 EV |
| Metering modes | • 1200-zone multi-segment • Center-Weighted • Spot |
| AE Lock | • AEL/AFL button • With shutter release half-press |
| AE Bracketing | • 3 or 5 frames • in 1/3, 1/2, 2/3, 2.0, 3.0 EV |
| Exposure compensation | • -5 to +5 EV • 1/3 EV, 1/2 EV steps selectable |
| Shutter speed | • 30 -1/8000 sec. • Bulb • Flash X-sync 1/250 sec |
| White balance | • Auto • Daylight • Shade • Cloudy • Incandescent • Fluorescent (Warm white /Cool white/ Day white/ Daylight) • Flash • Kelvin temp (2500 - 9900K, 100K steps) |
| WB fine tuning | Yes (magenta/green bias) |
| WB Bracketing | 3 frames, H/L selectable |
| Color space | • sRGB • Adobe RGB |
| Image parameters | • Standard • Vivid • Neutral • Clear • Deep • Light • Portrait • Landscape • Sunset • Night Scene • Autumn leaves • Black & White • Sepia (Contrast (-3 to +3 steps) • Saturation (-3 to +3 steps) • Sharpness (-3 to +3 steps) |
| Drive modes | • Single • Continuous Hi (8 fps) • Continuous Lo (3 fps) • 12 fps via high-speed mode |
| Continuous buffer | • 13 JPEG Extra Fine images • 18 JPEG Fine images • 18 JPEG Std images • 13 RAW images • 11 RAW+JPEG images |
| Self-timer | • 2 sec • 10 sec |
| Flash | • Auto op-up • ADI flash / Pre-flash TTL / Manual flash • Guide no. 12 (ISO 100) • Flash off, Autoflash, Fill-flash, Rear sync., Slow Sync., Red-eye reduction (On/Off), Wireless • Flash exposure compensation: Up to +/- 3EV in 1/3, 1/2EV steps |
| Flash X-sync speed | 1/250 sec |
| External flash | • Hot shoe |
| Viewfinder | • Eye-level fixed XGA OLED, 1.3 cm (0.5" type) electronic viewfinder • 2,359,296 dot resolution • Magnification approx.1.09x • 100% frame coverage |
| Live view | • Display Real-time image adjustment display (reflects exposure compensation, white balance, Creative Style ) • Focus Magnifier: 5.9x, 11.7x |
| DOF preview | Yes |
| Orientation sensor | Yes |
| LCD monitor | • 3.0" TFT tilt-LCD monitor • Xtra Fine LCD with TruBlack technology • 921,600 dots • Approx 100% frame coverage • Auto / Manual (5 steps between -2 and +2) / Sunny Weather |
| Playback functions | • Single (with or without shooting information) • RGB histogram and highlight/shadow warning • 4/9-frame index view • Enlarged display mode (L: 13.6x, M: 9.9x, S: 6.8x) • Auto Review (10/5/2 sec., Off) • Image orientation (On/Off) Slideshow • Panorama scrolling • Folder selection (Still) • Forward/Rewind (movie) • Delete • Protect |
| Connectivity | • USB 2.0 (High Speed) • HDMI type C • external microphone |
| Print compliance | • Exif Print • Print Image Matching III • DPOF setting |
| Storage | SD/SDHC/SDXC/MemoryStick Pro Duo |
| Power | • NP-FM500H Lithium-Ion rechargeable battery (1650 mAh) • Battery charger included • Optional AC adapter • Battery life Approx 470 shots with viewfinder,530 in Live view mode (CIPA standard) |
| Dimensions | 143 x 104 x 81 mm |
| Weight (camera body) | Approx. 653g (1 lb 7 oz) |
| Weight (camera body, card and battery) | Approx. 732g (1 lb 9.8 oz) |
Body & Design
In keeping with the A77's high-end status, it is positively encrusted with buttons that give direct access to its features. Better still, several of these buttons are customizable, allowing quick access to the settings you find yourself using most frequently. The AEL, AF/MF and ISO buttons can all be customized to hold one of 28 functions, from traditional shooting parameters such as drive mode and ISO through to processing features such as DRO and Picture Effects. It's a comprehensive list and delightfully free of restrictions (you can swap the ISO and AEL buttons if you fancy, or set all three to activate Smart Teleconverter if you're feeling especially perverse).
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| The A77 has lost the A700's obvious Konica Minolta 'heritage' styling but retains its solid build and comfortable grip. |
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| The A77 has a similar number of external buttons to its forebear but, in the light of the way the market has evolved, some of their functions have changed. The movie record button and Smart Teleconverter buttons replace the 'C' button but all the other functions are still represented. Overall, the only loss of direct control is the lack of metering mode switch. |
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The A700's joystick makes a return but sadly its 'QuickNavi' interactive control panel doesn't - you can choose to show a display of all the camera's settings on the rear screen but you can't get in and edit the settings, other than engaging the standard Function menu.
High resolution OLED EVF
One of the key technologies Sony was waiting for before launching an A700 replacement was a suitably high resolution EVF. The existing, field sequential 1.44M dot EVFs used in the first generation SLTs stand up reasonably well against the small optical finders found in the entry-level DSLR class, but were never likely to win over photographers used to the relatively large pentaprism viewfinder in the A700 and its competitors. Sony is certainly confident about it, and are suggesting that it's close enough to the quality of a high-end optical viewfinder that the advantages (the ability to preview exposure and white balance, or to gain-up for working in low light), outweigh the areas in which it isn't as good.
The EVF display in the A33 and A55 (and still-current A35) showed an 800 x 600 pixel array, updated one color at a time, which could lead to a rainbow-like 'tearing' effect if moved quickly. The OLED Trufinder that Sony is now using is a very different beast - its 2.4M dots are able to provide a 1024 x 768 pixel display and do so with a progressive update. As a result, the viewfinder not only gives a more detailed view but also one that's free from tearing.
The other great advantage of EVFs is that they aren't constrained by the size of the camera's sensor - even the best APS-C sensor cameras have small viewfinders when compared with inexpensive film SLRs. Trying to magnify the APS-C-sized reflection from the reflex mirror results in a darker viewfinder. With an electronic viewfinder, there is no such connection, so the size and brightness of the finder is dependant only on the current state of the technology. In the case of the A77, its 100% coverage, 1.09x magnification finder is essentially the same size as the immense optical finder in the A900.
Electronic first curtain shutter
As well as its high pixel count and 60fps 1080 output, the latest EXMOR CMOS sensor has a feature that lends a great deal to the capabilities of the cameras it's used in: the ability to act as the first curtain of the shutter. It's something we've seen on Canon DSLRs dating back to the EOS 40D - the idea that you start with the physical shutter fully open, and begin the exposure by activating the sensor electronically, one line at a time. The exposure is then ended when the physical shutter travels down across the sensor, blocking off the light.
The advantage of such a system is that you don't need to cock the shutter or wait for it to mechanically trigger - helping significantly improve the shutter response time. This ability is made use of across the latest NEX and SLT cameras, but offers a more obvious benefit in the mirrorless models. Side-by-side comparisons with the A700 show the A77 is a fraction more responsive (though the difference is measured in milliseconds, well below anything you're ever likely to notice).
Full-time phase-detection AF
The advantage of the SLT design - and the reason why Sony uses it - is that it always redirects light to a DSLR-style phase-detection AF sensor. Phase detection has two great advantages over contrast detection systems - firstly, it is able to determine exactly how to move the lens to achieve focus from a single reading (contrast-detect AF has to move the lens through its focus range to find focus) but, more importantly, phase detection technology is more refined - around 40 years of research and development has been applied to PDAF in SLRs.
As with the implementation in previous SLT models, there are some limitations placed on the amount of exposure control you can take with the A77 if AF is to be maintained in the 12fps and video modes. For instance, although the A77 now offers aperture-priority, shutter-priority and manual exposure modes for video recording, these are only available once manual focus has been selected.
The A77 is free of the overheating concerns during movie shooting that affected the A55 (recording times could drop as low as 6 min at 30°C with SteadyShot switched on). Sony estimates the A77 can shoot for its full 29 minutes at 30°C, dropping to 13 minutes only when the ambient temperature rises to 40°C.
Object Tracking
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| Pressing the joystick button once brings up this screen. Pressing it again sets the target to the object in the center of the frame. | The target then dances around the screen, attempting to track the subject. When you try to focus the camera will use the AF point nearest the subject, lighting the target box up green when it's in focus. |
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Articulated screen
The A77 has possibly the most flexible articulating screen yet seen on any stills-orientated camera. It uses a swivel-and-tilt joint, that is itself affixed to an arm that folds out from the back of the camera. This allows a huge range of positions to be adopted, including setting the screen facing forwards over the top of the viewfinder housing. (About the only thing you won't be able set it up for is a self-portrait with the camera on a tripod using on-camera flash.)
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