Digital SLR

Following the release of the entry-level A230, A330 and A380 models in May, Sony announced two slightly more advanced models - the A500 and A550 - in late August at the same time as it unveiled its advanced DSLR-A850 model. We've already reviewed the A230, A380 and A850 so it's interesting to look at the ‘intermediate' A550, which is pitched at photographers who want a capable, high-resolution DSLR without paying the high price demanded for the ‘full-frame' models.

The A550 and A500 are very similar, to the extent of sharing the same user manual. However, the A550 offers slightly higher resolution in its sensor and LCD monitor, an additional faster continuous shooting speed setting and a larger buffer memory. On the downside, its battery capacity is slightly lower and it's two grams heavier than its sibling. The table below highlights the key differences between these two models.

Build and Ergonomics
Like its entry- and mid-level siblings, the body of the A550 is made mainly from moulded polycarbonate plastic. Overall build quality is modest for the camera's price tag. The top panel is gunmetal grey, while the remainder of the body is black. A textured covering has been applied to most of the front panel and there's a textured thumb pad on the rear panel as well. The shutter release button and surrounding on/off switch are also plastic but shiny to simulate a metallic look.

A glossy black vertical strip on the front of the hand grip characterises Sony's second-generation entry- and mid-level DSLRs. The grip on the A550 is larger than the grip on the A230 and more comfortable for users with normal-sized hands. The single control dial is located at the top of the grip, just below the shutter release, where it's easily accessed.

Unfortunately, the width of the top panel means some juggling is required to reach the buttons for the Live View/OVF switch, D-Range, Drive and ISO buttons. It's difficult to use these buttons when the camera is held up to the eye. Although access is easier when you're shooting with Live View mode, the left hand is generally required to change camera settings.


Front view of the Sony DSLR-A550 without a lens, showing the metal mounting plate. (Source: Sony.)

Angled front view with the 18-55mm kit lens. (Source: Sony.)


Top view of the A550 showing the grip width, position of the controls and mode dial. (Source: Sony.)

The adjustable LCD monitor is similar to the original design that was introduced in the A350 and also used in the A330 and A380 models. The top of the monitor panel can be pulled down through 90 degrees, while the bottom of the panel can be tilted upwards through a slightly greater angle. The LCD panel boasts the same high (921,000-dot) resolution as offered on the A850 and A900.

It's an excellent screen that provides high resolution for checking shots plus above-average readability in outdoor lighting. However, like the monitor on the A380, it doesn't quite cover the sensor's field, although this will be irrelevant unless precise framing is critical in Live View mode.



Two views of the tilting LCD monitor on the A550 that makes it easier to take high- or low-angle shots. (Source: Sony.)

The viewfinder on the A550 only covers a 95% of the sensor's field of view and its 0.8x magnification sits between the magnifications offered by the A230 and A380. Like the other finders, it's not over-bright. Its 19mm eye relief is less than the A380 but more than the A230. However, it's compromised by the fact that the LCD mounting protrudes several millimetres out from the camera body.


Rear view of the A550 showing the control buttons and Graphic display interface. (Source: Sony.)

These finders are relatively dim because the additional sensor used for the Live View function takes up space in the reflex mirror housing. This means the pentamirror used to provide the reflex view is reduced in size and less able to provide the light levels offered in the A850 and A900 finders.

The mode dial is the same as that on the A380 and the Menu and Fn buttons are located in much the same places. However, instead of forcing the arrow pad to do double-duty and provide access to the Display, ISO and Drive settings, separate buttons have been provided on the A550 to access these functions. The same slider switch is located on the right side of the flash housing for switching between the optical viewfinder (OVF) and Live View modes.

We've already covered Sony's Quick AF Live View technology in our review of the DSLR-A350 so we won't elaborate on it here. Moving the slider to the Live View position blocks off the optical viewfinder, allowing fast phase-detection autofocusing with the sensor in the viewfinder housing. In dim lighting, the view on the LCD screen can become quite noisy, making it difficult to check focusing accuracy.

The Live View function has also been extended with the addition of Face Detection and Smile Shutter technologies, both of which can only function in the Quick AF Live View (and not when the viewfinder is used for composing shots). The Face Detection function can identify up to eight human faces in a scene and will fine-tune exposure and white balance settings to produce natural-looking skin tones. Smile Shutter detects faces in Live View mode and automatically records a shot when a smiling face is detected.

However, Sony has added a button to the top panel labelled MF Check LV. Pressing this button raises the mirror giving you a noticeably brighter view through the camera's primary sensor. Manual focusing is the only method supported in this Live View mode - and no depth-of-field preview is provided.

Like the A380, the A550 has dual memory card slots that accept Memory Stick PRO Duo and SD/SDHC memory cards. Although you can insert both card types at the same time, you must select which card to record to with a slider in the card compartment. Unlike higher-end DSLRs, the A550 can't write to both cards simultaneously; nor can you transfer files from one card to the other.

Controls
The A550 provides most of the adjustable controls photo enthusiasts require. The mode dial carries the standard Auto, P, A, S, M plus six scene pre-sets (Night View, Sunset, Sports Action, Macro, Landscape and Portrait) and a flash-off setting. Pressing the Fn (Function) button in shooting mode opens a menu list covering 10 functions: Drive mode, Flash mode, Autofocus mode and AF area are ranged down the left side of the monitor while the ISO mode, Metering mode, Flash compensation, White balance, D-Range Optimiser and Creative Style appear on the right. 

The Fn menu display with the AF area mode selected.

When you power-up the A380, the display on the LCD monitor will depend on whether you've set the camera to Live View or OVF (optical viewfinder mode). In Live View mode, four display options are available: the standard display with basic shooting data below the image frame, basic data plus a small brightness histogram, basic data with a Function overlay and basic data plus a graphic exposure guide.


Display options in Live View mode.

With the optical viewfinder selected, the camera will power up with one of two displays: Standard or Graphic.


The Standard display is shown on the left with the Graphic display on the right.

Both sets of displays are slightly different from those provided by the A380 and a similar Help Guide, which displays a brief text explanation whenever the shooting mode is changed, is also available.

The Help Guide shown with AF Area mode selection.

The Night View setting has been dropped from the Creative Style settings, leaving users a choice of: Standard, Vivid, Portrait, Landscape, Sunset and B/W modes, all of which are adjustable. In an advance on the A380, the A550 provides five levels of D-Range Optimiser settings, rather than the off, standard and advanced settings in the A380.

However, Sony has added a new Auto HDR (High Dynamic Range) mode that can combine two frames taken in rapid succession and extract the maximum amount of shadow and highlight details from them. Users can adjust the bracketing range by up to three stops in half-stop increments to cover subjects with varying brightness and contrast ranges.

The Bionz image processor and a larger buffer memory have enabled Sony to add a new Speed Priority continuous shooting mode to the Drive mode settings, extending the High and Low speed modes offered in the A550 and A380 models. With this mode, capture speeds up to seven frames/second can be achieved. Focus and exposure are locked with the first shot in each burst. This mode requires using the optical viewfinder to frame shots. It's usable with the auto, P, A, S and M shooting modes as well as the Sports scene preset but blocked for other scene modes. JPEG size and quality remain adjustable.

The most conspicuous missing feature in the A550 (and its sibling) is the ability to record video clips. We're not sure why Sony omitted this function as it has become almost mandatory in current DSLR cameras. Potential buyers will need to decide whether or not it's important.

Sensor and Image Processing
The sensor in the A550 appears to be the same chip as in the A380 and offers an effective resolution of 14.2-megapixels. It's partnered with Sony's Bionz image processor. As in other Sony DSLRs, image files can be recorded in JPEG or ARW.RAW format and the camera supports two aspect ratios; 3:2 and 16:9. Three image sizes and two Quality (compression) levels are available for JPEG files. Simultaneous RAW+JPEG capture is offered but the image size is fixed at Large and the quality is set to Fine. 
The Medium JPEG images are slightly smaller than those in the A380 but compression is significantly less with both Fine and Standard settings. Typical file sizes are provided in the table below.

Two types of noise reduction processing are provided, separately covering long exposures and high ISO settings. Long-exposure NR, which is available for exposures longer than one second, can only be switched on or off. It uses the dark-frame subtraction method, which roughly doubles image processing times.
High-ISO NR kicks in automatically at ISO settings of 1600 and above and is applied to both raw and JPEG files. You can choose between two settings - normal and high - but can't opt for no NR processing. Both noise reduction systems can be switched off manually in the camera menu. 

Playback and Software
The A550 offers essentially the same playback options as other Sony DSLRs, with single-frame, index (4 or 9 frames), playback zoom (7.2x  to 14x), slideshow, auto and manual image rotation, a choice between luminance and RGB histogram and shooting data displays. Individual shots can be marked for protection you can delete selected shots or all images on a card.

DPOF tagging for automated printing is also available. The camera is also compatible with Sony's Photo TV HD standard, which supports Full HD quality playback on Sony HDTV sets when the camera is connected via an HDMI cable (not supplied).

 The supplied software disk contains the latest versions of Sony's standard software applications: Image Data Converter SR V. 3.1, and Image Data Lightbox SR V. 2.1, and Picture Motion Browser V. 4.3.01. We've already covered these applications in our review of the Sony DSLR A900. The Remote Camera Controller V. 2.0 provided with Sony's top-end DSLRs is not included.

Performance
Not surprisingly, image files captured with the review camera and 18-55mm kit lens were similar in tonal quality and colour rendition to those from the A230 camera we reviewed in late September. And, like the A230, the A550 was not supported in Adobe Camera Raw when our Imatest assessments were carried out so raw files had to be converted with the bundled Image Data Converter SR application. This produced unimpressive results from the raw files we captured.

Overall colour accuracy was good for both JPEG and converted ARW.RAW files, with slightly elevated saturation and minor shifts in reds, blues and cyan. The DRO function provided a wider degree of control over tonal rendition than the A230 offers and provide valuable for shooting in bright, outdoor lighting and strongly-backlit situations. Examples are shown in the Sample Images section at the end of this review.

Imatest showed the camera to be capable of the resolution expected for 14-megapixel cameras with both JPEG and converted ARW.RAW files. Interestingly, the raw files converted with Image Data Converter SR delivered slightly lower resolution than the JPEGs Edge softening was detected with both file types and we suspect it to be largely due to the kit lens. The graph below shows the results of our Imatest tests at different apertures across the focal length range, based on JPEG files.

Image noise was negligible up to ISO 400, although by ISO 3200, pattern and colour noise had become obvious in long exposures with the in-camera noise-reduction processing turned off.  Shots taken at ISO 6400 and 12,800 were noticeably noise-affected and applying high ISO noise reduction tended to soften images without significantly reducing noise levels.

Flash shots were less noise-affected than long exposures but noise became obvious at ISO 6400.  Resolution tailed off gradually as sensitivity was increased and, although shots taken at ISO 3200 were of printable quality this was only at snapshot size. The graph below shows the results of our Imatest tests.

Edge and corner softening could be seen in most shots with a moderate degree of enlargement. Coloured fringing was also found in many outdoor shots. (An example is reproduced in the Sample Images section.) Lateral chromatic aberration depended on the focal length setting but was mainly in the ‘low' band, with occasional dips into the ‘moderate band'. In the graph below, which shows the results of our Imatest tests, the red line marks the boundary between ‘negligible' and ‘low' CA, while the green line separates ‘low' from ‘moderate' CA.

The test camera's flash performance was similar to the A230. We found no evidence of vignetting in flash exposures with the kit lens and exposure levels were even across its focal length range.  With all ISO settings, the flash had sufficient power to produce correct and evenly-balanced exposures.

The body-integrated image stabiliser enabled us to use shutter speeds as slow as 1/2 second with the lens at the 18mm position and 1/15 second at 55mm. In both cases, this represents more than 50% of shots acceptably sharp in sequences of 20 shots taken in the single-shot mode.

Auto white balance performance was well above average, with shots taken under incandescent lighting having only a slight warm cast and shots in fluorescent lighting being virtually colour cast-free. For both lighting types, the pre-sets tended to over-correct colours but the manual measurement system delivered cast-free images. Plenty of in-camera adjustments are provided for tweaking images as you shoot.

The review camera powered up almost immediately and shot-to-shot times averaged 0.35 seconds. We measured an average capture lag of less than 0.1 seconds when the viewfinder was used for shot composition and 0.3 seconds with Live View mode. In both cases, lag times were eliminated by pre-focusing. It took 3.1 seconds, on average, to process an image file, regardless of whether it was taken in JPEG or RAW format and RAW+JPEG pairs were processed in 3.2 seconds on average.

For our burst capture timing tests we used a Verbatim Class 6 SDHC memory card. In the High-speed burst mode, we recorded a burst of 10 Large/Fine JPEG frames in 2.2 seconds. Shot intervals slowed gradually from 0.2 seconds to 0.3 second between frames in this burst. It took 3.4 seconds to process this burst.

Changing to raw file capture, we recorded a burst of 10 shots in 2.5 seconds, with capture speeds slowing after the seventh frame recorded. It took 3.9 seconds to process this burst. For RAW+JPEG recording, the camera captured seven frames in 1.5 seconds before slowing noticeably. It took 4.5 seconds to process this burst. In the Sport Priority Continuous Advance mode, the camera recorded 10 Large/Fine JPEG frames in 1.3 seconds but took seven seconds to process the burst.

The review camera's AF system was quite noisy, compared with other camera's we've reviewed but generally very effective. We found the eye-start AF shortened the times required to focus on subjects when the viewfinder was used for shot composition. Touching the shutter button locked focus quickly in both OVF and Live View modes, which is reassuring for photographers who prefer using the Live View mode. The AF system also performed well in both bright and dim lighting.

Buy this camera if:
- You want an affordable interchangeable-lens camera with fast autofocusing regardless of whether Live View or the viewfinder is used for shot composition.
- You want body-integrated image stabilisation that works with all lenses.
- You'd like a wide range of user-adjustable controls and functions.
- You require fast burst speeds and a generous buffer capacity.
- You could make use of the extended sensitivity range, despite its associated image noise.
Don't buy this camera if:
- You'd like the ability to shoot both still pictures and HD video clips.
- You require high resolution and low noise levels at ISO settings over 1600.
- You prefer converting raw files with Adobe Camera Raw (the current edition doesn't support raw files from the A550).

IMATEST GRAPHS
JPEG images

Raw images converted in Image Data Converter SR

SAMPLE IMAGES

Auto white balance with incandescent lighting.

Auto white balance with fluorescent lighting.

18mm focal length, ISO 200, 1/250 second at f/10.


100% crop from the above image showing coloured fringing and corner softening.

Close-up: 45mm focal length, ISO 200, 1/80 second at f/5.6.

Close-up showing bokeh: 55mm focal length, ISO 200, 1/60 second at f/5.6.

Portrait with built-in flash: 55mm focal length, ISO 400, 1/20 second at f/5.6.

25 second exposure, 35mm focal length, ISO 200, f/8.

6 second exposure, 35mm focal length, ISO 3200, f/13.

3.2 second exposure, 35mm focal length, ISO 12800, f/18. High ISO noise-reduction set to Normal.

Flash exposure at ISO 200; 55mm focal length, 1/80 second at f/5.6.

Flash exposure at ISO 3200; 55mm focal length, 1/80 second at f/5.6.

Flash exposure at ISO 12800; 55mm focal length, 1/80 second at f/8.

Contre-jour sunset with D-Range Optimiser set to Off: 20mm focal length, ISO 400, 1/2000 second at f/13.

The same subject with D-Range Optimiser at Lv.1: 20mm focal length, ISO 400, 1/1600 second at f/13.

The same subject with D-Range Optimiser at Lv.3: 20mm focal length, ISO 400, 1/2000 second at f/13.

The same subject with D-Range Optimiser at Lv.5: 20mm focal length, ISO 400, 1/2000 second at f/13. (Traces of posterisation can be seen near the centre of the picture.)

A shot taken with the Auto HDR mode: 20mm focal length, ISO 400, 1/2000 second at f/14.

Image stabilisation tests: hand-held at 20mm focal length, ISO 200, 1/2 second at f/7.1.

Image stabilisation tests: hand-held at 35mm focal length, ISO 3200, 1/15 second at f/8.

Image sensor:  23.4 x 15.6 mm Exmor CMOS sensor with 14.6 million photosites (14.2 megapixels effective)
A/D processing: 12-bit
Lens mount: Sony Alpha and Minolta AF lenses
Focal length crop factor: 1.5x
Image formats: JPEG (Exif 2.21), RAW 2.1 Raw; RAW+JPEG capture supported
Image Sizes: 3:2 aspect ratio: 4592 x 3056, 3344 x 2224,  2288 x 1520; 16:9 aspect ratio: 4592 x 3,056, 3344 x 2224, 2288 x 1520
Image Stabilisation: Image-sensor shift mechanism (body-integrated)
Dust removal: Image sensor shift plus charge protection coating on low pass filter
Shutter speed range: 30 to 1/4000 second plus Bulb; X-synch at 1/160 second
Exposure Compensation: +/- 2 EV in 1/3 EV steps
Exposure bracketing: 3 continuous or single exposures selectable, in 0.3 or 0.7-stop increments
Self-timer: 2 or 10 seconds delay
Focus system: TTL phase-detection system with 9 AF points
Focus modes: Single-shot AF, Auto AF, Continuous AF, Manual Focus
Exposure metering: 40-segment honeycomb-pattern SPC with Multi Segment, Centre-Weighted, Spot patterns
Shooting modes: Program AE (AUTO, AUTO with Flash Off, P), Aperture priority, Shutter priority, Manual plus Portrait, Landscape, Macro, Sports, Sunset, Night view / Night portrait scene presets
Picture Style/Control settings: Standard, Vivid, Portrait, Landscape, Sunset, B/W
Colour space options: sRGB, Adobe RGB
D-Range Optimiser: Mode: off / Auto, Levels 1-5)
ISO range: Auto, ISO 200 to 12,800 in 1-stop increments
White balance: Auto, Preset (Daylight, Shade, Cloudy, Incandescent, Fluorescent, Flash), Custom
Flash: Built-in Auto Pop-up TTL flash with Auto (Flash-off), Auto, Fill flash, Red-eye reduction, Rear Sync, Slow sync and High-speed sync modes plus Wireless operation with compatible external flash
Flash exposure adjustment: +/- 2 EV in 1/3 EV increments
Sequence shooting: Up to 5 fps with viewfinder, Up to 4 fps in live view mode, Up to 7 fps in Speed-priority mode; Max. 32 frames JPEG/Fine; 14 ARW.RAW frames; 7 RAW+JPEG
Storage Media: Dual slots for Memory Stick PRO Duo and SD/ SDHC memory cards 
Viewfinder:  Fixed eye-level, penta-Dach-mirror with Spherical Acute Matte focusing screen; 95% FOV coverage; 0.8x magnification (with 50mm lens at infinity); approx. 19mm eye relief; dioptre adjustment of -2.5 to +1.0 dpt
LCD monitor: 3.0-inch Xtra Fine TFT LCD with 921,600-dots and 100% field of view
Live View: Pentamirror tilt system with dedicated image sensor, 90% FOV coverage 1.4x or 2x Smart Teleconverter function; histogram and real-time image-adjustment displays
Video Capture: No
Data LCD:  No
Playback functions: Single-frame, Index (4 or 9 frames), Enlarge (7.2x  to 14x), Slideshow, Picture rotation (auto mode available), Histogram (independent luminance/RGB available), Shooting information
Interface terminals: USB 2.0 Hi-Speed (mass storage mode / PTP mode); HDMI type C mini-jack; DC IN;  remote terminal
Power supply: NP-FM500H rechargeable lithium-ion battery (CIPA rated for Approx. 950 shots with OVF or approx. 480 shots with live view
Dimensions (wxhxd): Approx. 137 x 104 x 84 mm (body only)
Weight: Approx. 599 grams