DigitalCameraReview.com
Sony Alpha SLT-A55V Review
by Jim Keenan -  10/4/2010

Announced this past August for a September debut in the market (along with the Alpha a33), the Sony Alpha SLT-A55V is the higher resolution and faster continuous shooting half of this duo. DCR.com Editor Allison Johnson shot the a55 at a Sony function in Jackson and Yellowstone, Wyoming, and came away impressed with the camera's speed. Fast continuous shooting rates and a capable autofocus combined with good image and color quality to create a very good first impression.

Sony alpha a55


A production a55 has found its way to my door, with a slightly longer shooting window of opportunity than that afforded Allison, so we'll get to explore this camera's ins-and-outs a bit more extensively. In her first look, Allison alluded to "...some interesting new technology going on inside the a55..." That might be "Translucent Mirror Technology" and would seem to be at least partly responsible for the shooting speed of the a55, along with claims of fast and efficient autofocus for still or movie capture.

In a traditional film SLR or DSLR, light enters the camera through the lens and is reflected by a mirror to the viewfinder screen. When the shot is taken the mirror flips up to allow the light to strike the film or sensor, then flips back down for the next shot. In the a55 the light strikes the mirror, but some of it is reflected to the viewfinder while the rest passes through the mirror to the sensor. The mirror never moves in the a55, which produces a continuous shooting rate of up to 10 frames per second (fps). For video work, this means you can use the viewfinder for capture.

Sony alpha a55

Canon's EOS 1D Mark IV shoots at 10 fps and Nikon's D3/3S goes 9 fps with standard mirrors, so obviously Sony's translucent mirror is not a requirement for high speed shooting rates. But when you consider the Mark IV body alone will set you back $5,000 while the D3S runs the tab out to $5200, the a55 is an outstanding bargain on shooting speed alone at $750. But the a55 packs a lot more features than just a pro-class shooting speed.

You can capture video in AVCHD or MP4 HD 1080i formats and the 3.0-inch LCD monitor articulates. The sensor is a Sony Exmor APS HD CMOS with 16.2 megapixel resolution. Sensor size is 23.5x15.6mm, (same as the Exmor APS-C CMOS models in the other non full-frame Alphas) and provides a 1.5x crop factor. There are the requisite full manual exposure controls along with a very functional 16:9 panorama mode that can capture regular or 3D images and 8 scene-specific shooting modes including macro. An integrated GPS allows for automatic geo-tagging of stills and videos. Memory Stick PRO Duo/PRO-HG Duo or SD/SDHC/SDXC memory media are compatible. The camera is available as a body-only or packaged with an 18-55mm f/3.5-5.6 zoom lens, as was our review model. Here's the focal range offered by the kit lens:

Sony a55 Test Image
Wide Angle, 18mm

Sony a55 Test Image
Telephoto, 55mm

Lens compatibility includes over 30 A-mount interchangeable lenses and the body is stabilized with Sony's SteadyShot INSIDE system, reported to offer up to 4 stops of anti-shake correction. Sony includes a body cap, charger and battery, shoulder strap, USB cable and CD-ROM software with each camera.

Our review model a55 has to be back in Sony's hands a week from today, so let's not waste any time putting it to work.

BUILD AND DESIGN
The a55 will immediately be recognizable as a DSLR, albeit on the smaller end of the size spectrum. The body is composite and seems well put together - fit and finish is in line with the camera's price point.

Sony alpha a55

Ergonomics and Controls
The first thing I noticed about the a55 was the size - it measures out at 4.9x3.58x3.33 inches, which puts it the ballpark with the Olympus E-450 as one of the smaller DSLRs. With much of the camera back dedicated to the 3.0-inch monitor and a thumb rest, the space that's left is packed with buttons and controls. Ditto for the top of the body. Even so, I had no trouble with inadvertent activations.

Sony alpha a55

The deeply sculpted handgrip offers a secure hold, but clearance between the grip and the lens barrel was snug for my fingers. My shooting finger fell naturally across the shutter button, but at the second pad of the finger - it required a conscious effort to pull the finger back and activate the shutter with the finger tip. Folks with large hands should definitely check the feel of the camera before buying.

Sony alpha a55

The controls themselves are logical and intuitive. There's a dedicated movie capture button, and function and d-range buttons take you to menus for available camera settings based on your particular shooting mode. Some controls have a dual function depending on the context in which they're activated - the function button also serves as the AF area selection control, for example.

Menus and Modes
Menus are straightforward and largely intuitive. There is a three page recording menu, two page custom menu, two page playback menu and one page memory card tool and clock setup menus.
Shooting modes run the gamut from fully manual to fully automatic with specific scene options thrown in for good measure.

The sweep shooting mode on the a55 is very capable and easy to use. You need to allow a good margin at the top and bottom of the frame (right and left if shooting in the vertical format), but once I got the hang of composition the a55 produced a steady diet of nice panoramas, all hand held. Here's my first try with the San Diego harbor waterfront and the keeper with the right composition.

Sony a55 Test Image

Sony a55 Test Image

Display/Viewfinder
The 3.0-inch LCD monitor on the a55 has a 921,000 dot composition and is adjustable for 5 levels of brightness manually in addition to an auto setting. The monitor may be flipped down through 180 degrees of travel and rotated through 270 degrees; coverage is listed as 100 %. In bright sunlight the monitor can be difficult to use for image composition and capture, although the flip/rotate features can be of help in some cases.

Sony alpha a55

The electronic viewfinder has a 1.15 million dot composition and diopter adjustment to accommodate varying degrees of eyesight. Coverage is 100%.

PERFORMANCE
An advertised continuous shooting speed of up to 10 fps and 1080i video are some fairly impressive figures, even for a camera that trails only the a850 ($2000) and a900 ($2700) in Sony's pricing structure. Let's see what else the a55 has in its bag of tricks.

Shooting Performance
As DSLRs go, the a55 is a little poky to power up, presenting a focus icon in a bit less than a second. I got off a first shot in about 1.4 seconds, and single shot-to-shot times ran about 1.25 seconds. That "up to 10 fps" continuous shooting rate might be a bit conservative - I timed 17 shots in 1.57 seconds for a 10.8 fps average with a class 10 SDHC memory card and bright daylight. The a55 calculates exposure for the first shot in the burst and applies that setting to all subsequent shots in the sequence.

Shutter Lag (press-to-capture, pre-focused)

Camera Time (seconds)
Nikon D3S 0.01
Canon Rebel T2i 0.02
Pentax K-7 0.02
Sony Alpha SLT-A55V 0.04

AF Acquisition (press-to-capture, no pre-focus)

Camera Time (seconds)
Sony Alpha SLT-A55V 0.16
Nikon D3S 0.18
Canon Rebel T2i 0.18
Pentax K-7 0.29

Continuous Shooting

Camera Frames Framerate*
Sony Alpha SLT-A55V 17 10.8 fps
Nikon D3S 63 9.0 fps
Pentax K-7 19 5.3 fps
Canon Rebel T2i 170 3.7 fps

*Note: Continuous shooting framerates are based on the camera's fastest full-resolution JPEG continuous shooting mode, using the fastest media type available (300x CF, SDHC, etc.). "Frames" notes the number of captures recorded per burst before the camera stops/slows to clear the buffer.

AF acquisition times are DSLR quick - we measured 0.16 seconds - but shutter lag proved a bit slower at .04 seconds. Still pretty quick, but lagging a bit behind the best of the group. Equally important, continuous AF tracking is very good at that pro-level 10 fps. Here's the first and last shots of a 19 series burst at 10 fps.

Sony a55 Test Image
First
Sony a55 Test Image
Last

And here are shots 8, 10, 12 and 13 from the middle of the series.

Sony a55 Test Image
8
Sony a55 Test Image
10
Sony a55 Test Image
12
Sony a55 Test Image
13

Here's another series with focus established on the gull which then passes palm trees in the background. The a55 held focus on the bird even with objects now appearing in the background to potentially throw off tracking.

Sony a55 Test Image Sony a55 Test Image
Sony a55 Test Image Sony a55 Test Image
Sony a55 Test Image Sony a55 Test Image

The a55 flash guide number is listed as 12 in the Sony press release, but 10 in the user's manual supplied with the camera, both at 100 ISO. Assuming the manual is correct, flash range would be about 2.5 meters at f/4, or about 8.2 feet. Flash recycle time is listed as about 4 seconds; our review unit with a fresh battery recycled in a bit over a second in auto mode and moderate light. With ISO set to 100 and in dark conditions and f/32, recycle times ran about 3.5 to 3.75 seconds.

Battery life is listed as 330 shots using the electronic view finder and 380 with live view. Either way, those numbers lag well behind even entry-level DSLRs that all seem to get at least 500 shots per battery. The better numbers with the monitor are the result of the design being more power efficient. But whether you shoot with viewfinder or monitor, a camera with a 10 fps motor has the ability to run up your shot total in a hurry, so pack a spare battery or two.

Lens Performance
The Sony-branded 18-55mm kit lens features maximum apertures of f/3.5 at wide angle and f/5.6 at telephoto. Fairly standard numbers for similar lenses from other manufacturers, but not overly fast in any event. There was moderate barrel distortion at wide angle but the lens was quite distortion free at telephoto. Edges and corners had a just a hint of softness at both wide and telephoto, but overall the lens was fairly uniformly sharp. There was a bit of chromic aberration (purple fringing) on some high contrast shots at wide angle, and very little at telephoto, but in most cases it required enlargements in the 200 to 400% range to make the defects easily noticeable.

Sony alpha a55

One nice feature of the lens is a close focus distance of about 9.85 inches. The a55 has a macro setting, but even without that set the lens can get you pretty close in regular shooting modes. Here are two shots of an Anna's hummingbird that flew into and stunned himself on our sliding glass patio door. I picked him up and got some sugar water into him and grabbed the a55 as he got his wits back. Plain old aperture priority shot one-handed with no attention paid to trying to get the focal plane aligned to maximize the area in focus, but nice and close without going to macro.

Sony a55 Test Image Sony a55 Test Image

(And the little guy blasted off after about ten minutes seemingly none the worse for wear).

Video Quality
The a55 can capture video in the AVCHD format at 1920x1080i resolution; MP4 at 1440x1080 or 640x480 resolutions. Maximum clip length is 29 minutes in either format. AVCHD is recommended for viewing on HD television with MP4 suggested for internet use. Our sample video is MP4. While AVCHD is becoming more common, viewing requires an AVCHD-compatible device while the MP4 format is more universally recognized at this point. That will be a stumbling block in trying to share your AVCHD clips with friends without AVCHD compatible equipment.

Sony points to quick AF in movie mode as one of the benefits of the translucent mirror design of the a55, and the camera was quick to transition into movie mode and focus - one of the quickest video-capable still cameras I've reviewed. Another bonus is the ability to use the viewfinder for video capture. Zoom is available while capturing video and the microphone can be sensitive to wind noise. It also picks up noise from the camera when it auto focuses on a changing scene and establishes a new focus point. With a CMOS sensor, rolling shutter effect is in play during panning, but the effect is fairly well controlled in the a55 and requires exaggerated pan speeds to produce objectionable effects. Image quality was good, and the video component overall was one of the better ones I've reviewed.

Image Quality
Default images out of the a55 were good. Colors were accurate and perhaps a bit more saturated than in real life but pleasing and nicely sharp. There are contrast, saturation and sharpness settings that range from -3 to +3 in for manual shooting modes in the event the default settings don't meet user expectations.

The 16 megapixel sensor provides for files that take some cropping and still produce decent quality prints. The first image is the original shot; the image below it was sized to 12x8 inches and retains a 223 dot per inch density that will produce a good quality print.

Sony a55 Test Image

Sony a55 Test Image

Sony's color palette options will be familiar to Sony users. Here are the standard, vivid, portrait, landscape, sunset and black & white modes.

Sony a55 Test Image
Standard
Sony a55 Test Image
Vivid
Sony a55 Test Image
Portrait
Sony a55 Test Image
Landscape
Sony a55 Test Image
Sunset
Sony a55 Test Image
Black & White

The a55 offers DRO (D-Range Optimizer) and HDR (High Dynamic Range) settings that may be enabled to enhance the camera's apparent dynamic range. DRO "...divides the image into small areas and the camera analyses the contrast of light and shadow between the subject and the background, producing the image with the optimal brightness and gradation." HDR "Shoots three images with different exposures, and then overlays correctly exposed image, the bright areas of an under exposed image and the dark areas of an over exposed image to create an image with rich gradation. Two images are recorded: an image with the correct exposure and an overlaid image." Here's a motorcycle with and without DRO enabled.

Sony a55 Test Image
DRO Off
Sony a55 Test Image
DRO Auto

Both DRO and HDR have automatic and manual settings; DRO offers five levels of strength, HDR offers six.

Auto white balance was used for the shots in this review and worked well under a variety of light sources, but shot warm under incandescent light. The a55 offers daylight, shade, cloudy, incandescent, fluorescent, flash and custom settings, along with a color temperature option that allows you to designate a Kelvin temperature for your lighting conditions.

Sony a55 Test Image
Auto White Balance, 5500k fluorescent light

You can view the scene through the viewfinder or on the monitor as you adjust temperatures until they look right to you. Here's another one-handed shooting job with incandescent light and auto WB, along with one where I dialed in temperature until the colors looked "right". Focus was on the figurine for one and Simon on the other, but the color correction is unmistakable.

Sony a55 Test Image
Auto
Sony a55 Test Image
Temperature Adjusted

Multi-segment metering was used for this review, but there are center-weighted and spot options available. The a55 lost highlights on occasion in high contrast situations, but exposure compensation is available in manual shooting modes.

The a55 has a nominal ISO range from 100 to 12800. ISO 100 and 200 were hard to differentiate and for all practical purposes equal. ISO 400 picked up just the slightest bit of some graininess in isolated spots, but was very hard to tell apart from 200, particularly in smaller images. ISO 800 seemed to mirror 400 with colors being a bit less saturated. Images at ISO 1600 seemed softer overall than 800, with some loss of clarity in fine detail areas.

Sony a55 Test Image
ISO 100
Sony a55 Test Image
ISO 100, 100% crop
Sony a55 Test Image
ISO 200
Sony a55 Test Image
ISO 200, 100% crop
Sony a55 Test Image
ISO 400
Sony a55 Test Image
ISO 400, 100% crop
Sony a55 Test Image
ISO 800
Sony a55 Test Image
ISO 800, 100% crop
Sony a55 Test Image
ISO 1600
Sony a55 Test Image
ISO 1600, 100% crop
Sony a55 Test Image
ISO 3200
Sony a55 Test Image
ISO 3200, 100% crop
Sony a55 Test Image
ISO 6400
Sony a55 Test Image
ISO 6400, 100% crop
Sony a55 Test Image
ISO 12800
Sony a55 Test Image
ISO 12800, 100% crop
Sony a55 Test Image
ISO 25600
Sony a55 Test Image
ISO 25600, 100% crop

ISO 3200 seemed a bit softer again in fine detail areas, and colors that again seemed a bit less saturated. ISO 6400 seemed grainier with another loss in fine detail areas, and 12800 was much grainier, with fine details turning into smudges and much less intense color. Overall, on darker subjects the jump from 1600 to 3200 seemed to be where noise took its toll; lighter objects took their hit from the 3200-6400 increase. None of the ISOs look too bad in small images, and while the a55 hasn't re-written the book on ISO noise performance for DSLRs, its latest-generation sensor and processor seem to do a good job at this resolution level.

Ah, but just when you think you've heard it all on ISO noise, the a55 whispers in your ear "what about Multi Frame Noise Reduction (MNR)?" Seems that in the ISO settings there are "auto" and "auto ISO" options. Selecting "auto ISO" gets you MNR which rapidly captures 6 images to create a single image with lower noise. MNR goes from 100 to 25600 ISO. Capture time took a bit over 3 seconds in moderate light at 100 ISO; that time dropped to about 1.25 seconds in dimmer light at 25600. Hand holding seemed to produce decent results regarding camera shake with stationary and slow-moving subjects, but a stationary subject and camera support would be good options when possible. Here's 3200 through 12800 in regular ISO and MNR, plus 25600MNR, as well as 200 and 200MNR.

Sony a55 Test Image
ISO 200
Sony a55 Test Image
ISO 200 MNR
Sony a55 Test Image
ISO 1600
Sony a55 Test Image
ISO 1600 MNR
Sony a55 Test Image
ISO 3200
Sony a55 Test Image
ISO 3200 MNR
Sony a55 Test Image
ISO 6400
Sony a55 Test Image
ISO 6400 MNR
Sony a55 Test Image
ISO 12800
Sony a55 Test Image
ISO 12800 MNR
Sony a55 Test Image
ISO 25600 MNR

Not much to choose from between the 200s, but the higher ISOs in dim conditions favor the MNR shots. MNR has a fairly narrow window of opportunity because of the stationary subject/camera shake concerns, but if circumstances permit it looks like a viable way to go if you have to ramp up the ISOs.

Additional Sample Images

Sony a55 Test Image Sony a55 Test Image
Sony a55 Test Image Sony a55 Test Image
Sony a55 Test Image Sony a55 Test Image

CONCLUSIONS
There's not much to dislike about Sony's new Alpha a55. Good image quality and color rendition; a quick one-button video interface and 1080i resolution in AVCHD or MP4 formats; and pro-level continuous shooting (and the AF tracking skill to keep things in focus at those high shot rates) all seem like a bargain at the a55's $750 body-only sticker. There's a wide variety of lenses available and the camera body itself is compact and fairly light.


That compact body may pose problems for users with big hands, and the a55 starts up and shoots single shots a bit slower than most DSLRs. Battery life is low by DSLR standards. That's about it for the "wish it could be better" list. If you're already shooting the Sony system the a55 is a worthy addition for the continuous shooting rate alone. If you're considering a Sony the a55 is a most worthy consideration, even as your first DSLR.

Pros:

Cons: