BY: J. Keenan, DigitalCameraReview.com Contributor
Introduced in late August 2009, the Sony Alpha DSLR-A550 slots into the Sony lineup at the top of their entry level/consumer DSLR fleet of five bodies (in addition to the three other Alpha models comprising the prosumer and up class). The camera features a new 14.2 megapixel Sony Exmor CMOS sensor in the APS-C size format that produces a 1.5X crop factor (35mm film equivalent), as well as the newest BIONZ image processing engine and an ISO sensitivity range of 200 to 12800.
There are two distinct Live View modes, smile and face detection technology, two separate dynamic range management modes, an articulating 3.0 inch LCD monitor with 921k dot composition, up to a 7 fps continuous shooting rate and in-body stabilization. Automatic sensor dust removal, 6 specific scene shooting modes in addition to the usual DSLR menu of manual and semi-automatic modes, and an on-screen help guide and graphic display to further explain settings on the fly round out this fairly feature-rich model.
Following current Sony practice with their DSLRs, the A550 has no video capture capability. There are dual memory media slots for Sony's Memory Stick PRO Duo media as well as SD/SDHC memory cards, but Sony recommends the PRO-HG Duo card and will not guarantee "proper operation for all Memory Stick PRO Duo media functions."
The A550 is available in body-only or kit form with the Sony f3.5/5.6 18-55 SAM zoom lens. Sony includes a power cord, battery charger and battery, shoulder strap, CD-ROM software, USB cable, body cap and printed instruction manual with each camera. In addition to Sony-branded lenses (some by Carl Zeiss), the camera is compatible with Minolta Maxxum A mount lenses. Here's the view offered by that kit lens:
Wide Angle
Telephoto
When we shot the A550 briefly for a "first impressions" look at the camera, there didn't appear to be any areas of immediate concern save possibly some softness in image quality with the default settings. Did we discover anything during a more extensive shooting period to change our mind about this new Sony? Read on and find out.
BUILD AND DESIGN
The A550 features a two-tone composite body with rubberized material in strategic locations to facilitate a firmer grip. The composite might be a bit underwhelming for a camera body with an asking price north of $800, but the rubberized stuff feels about right and the overall build quality looks to be good.
|  |
Ergonomics and Controls
In typical DSLR fashion, the A550 features a deeply sculpted handgrip front and built-up thumb rest rear - the shooting finger falls naturally to the shutter button. The top and back of the body are covered with buttons and controls except for the thumb rest area, and the overall spacing and layout of the controls doesn't present any obvious conflicts that might encourage inadvertent activations. The most likely candidate for such a problem is the control dial which sits below the shutter button - in the manual or semi-auto shooting modes it only needs to be moved to change camera settings, but in practice it proved immune to accidental inputs.
The camera body has buttons providing quick access to ISO, shooting drive mode, dynamic range management options, auto exposure lock and exposure compensation. A "function" button takes you to a menu offering additional inputs: flash mode, autofocus (AF) mode, AF area, metering mode, flash compensation, white balance (WB) and creative style color options.
|
|
Live view fans can switch to the Quick Auto Focus live view mode by simply selecting the live view setting on the external live view/optical view finder (OVF) switch. From there, they can jump to the Manual Focus Check live view mode by merely pressing the MF Check button; in the alternative they may proceed directly to the manual mode by pressing the MF Check button without first switching to the auto focus mode. Here's a sample of a screen in both auto and manual live view - there are other overlays of information possible in both modes, including a histogram in auto that is not available with manual.
|
|
The Help Guide is activated with the "function" button and is on by default - it can provide guidance to folks unfamiliar with the controls, settings or potential impacts of changing settings on the camera. The shots that follow show the initial screen after pushing the function button and the subsequent screen after selecting "DRO AUTO"; the third screen is typical of the presentation when switching to a shooting mode, in this case shutter priority.
 |  |  |
The Help Guide can be disabled by internal menu and will probably be the second feature shut off by experienced shooters. What's number 1? We'll get to that in the Performance section.
The Graphic Display presents information on camera settings and can illustrate the relationship between aperture and shutter speed depending on the particular display chosen. Here are two variations:
 |  |
Help guide and graphic display information appear on the LCD monitor and are not available in the optical view finder, which displays only aperture, shutter speed, exposure compensation, stabilization status, and a flash ready light (if the flash is enabled).
Menus and Modes
While offering the usual DSLR manual and semi-automatic shooting modes, the A550 retains a fully auto mode and six specific scene modes that offer only the barest of user inputs.
- Auto: Camera handles all settings, user can select self-timer and flash only.
- Portrait: Camera handles all settings, user can select self-timer and flash only.
- Landscape: Camera handles all settings, user can select self-timer and flash only.
- Macro: Camera handles all settings, user can select self-timer and flash only.
- Moving subjects: Camera handles all settings, user can select high speed or speed priority continuous shooting and self-timer only.
- Sunset: Camera handles all settings, user can select self-timer and flash only.
- Night scene: Camera handles all settings, user can fire shutter via self-timer or remote commander only and has flash available.
- Program auto: Camera handles exposure settings, user has wide variety of input including drive, flash, AF and metering modes; AF area, ISO, flash compensation, WB, dynamic range management and creative style color options.
- Aperture priority: User sets aperture, camera sets shutter and user has all inputs listed for Program auto.
- Shutter priority: User sets shutter, camera sets aperture and user has all inputs listed for Program auto.
- Manual: User sets aperture and shutter, same inputs as Program auto.
Menus are simple and intuitive in the A550, running only about seven pages internally.
Display/Viewfinder
The A550's 3.0 inch LCD monitor has 921,000 dot composition and features automatic level adjustment as the default setting; five levels of brightness may be selected manually via an internal menu. The monitor is articulated and may be tilted up or down through 180 degrees as well as moved away from the camera body.
|  |
The monitor could be difficult to use in some instances in bright outdoor light, but the articulating feature was of some help in this regard. Coverage is 100% in playback, but only 90% in live view - framing and composition in live view will not show some parts of the final image. The shot below was composed in live view so the picture and its frame filled the monitor - the sections of wall at the sides were not visible when the shot was composed.
The camera's optical viewfinder features a diopter adjustment for varying levels of eyesight acuity and offers 95% coverage - image composition and final capture will be skewed again, but not to the degree of the monitor using live view to capture.
PERFORMANCE
All of you who skipped directly here from the Help Guide section to find out the first feature to disable should be ashamed. But since you're here... during the shoot for the first impressions story on the A550, nothing much jumped out as being of concern. Once I started wandering about doing more extensive shooting for the main article the A550 started behaving oddly.
I had the camera set for continuous AF, which should take place as long as the shutter is held at half-push. The problem was I could feel and hear the A550 doing its AF thing as I walked along with my finger nowhere near the shutter button. Setting the camera to auto and single-shot AF didn't fix things, nor did trying every shooting mode available. The camera was doing AF all by itself, and I'm thinking maybe I've got a faulty camera. After spending about an hour going over the instruction manual (when all else fails, read the manual!) it turns out the A550 was operating perfectly.
"Eye start AF" is an A550 feature enabled by default that causes the subject located in the viewfinder AF area to come into focus automatically as you look into the viewfinder. I wasn't looking into the viewfinder all the times the camera did the AF routine, but I was walking along carrying the camera in my shooting hand and as my arm would swing as I walked, the camera interpreted the proximity to my leg as the camera being looked into and activated the AF.
It's actually a pretty neat feature, but depending on how you carry your camera it does have the potential to drain the battery sooner due to performing AF unnecessarily. Personally, it would be the first thing I'd disable.
While the A550 can carry both Memory Stick and SD memory media, the type it use is designated by flipping a switch in the memory card compartment. I'd liked to have seen Sony set up the camera to automatically move on to the other media when one got full, rather than require the user to go into the compartment and switch the camera over.
While I'm not a big fan of live view, the A550 has the best system I've come across so far. The quick auto focus live view mode makes use of a separate imager that dramatically cuts AF time - and in fact you can shoot at speeds approaching 4fps in this live view mode! The A550 makes it easy to transition to either quick AF or the manual focus mode live view, but one drawback with going to manual is you'll be trying to focus by working against the focus motor in the camera unless you take the time to switch both the lens and the camera from AF to MF. Without the switch, manual focus is stiff and imprecise at best.
Shooting Performance
As one would expect from a DSLR, the A550 starts promptly - sensor cleaning is performed on shutdown by default - and acquires focus and shoots on a par with other competitors in the class. We measured shutter lag at 0.01 seconds and press-to-capture with no pre-focus at 0.20 seconds.
Shutter Lag (press-to-capture, pre-focused)
| Camera | Time (seconds) |
| Sony Alpha DSLR-A550 | 0.01 |
| Nikon D5000 | 0.02 |
| Pentax K-x | 0.03 |
| Panasonic Lumix DMC-GH1 | 0.06 |
AF Acquisition (press-to-capture, no pre-focus)
| Camera | Time (seconds) |
| Nikon D5000 | 0.19 |
| Sony Alpha DSLR-A550 | 0.20 |
| Pentax K-x | 0.25 |
| Panasonic Lumix DMC-GH1 | 0.37 |
Continuous Shooting
| Camera | Frames | Framerate |
| Sony Alpha DSLR-A550 | 16 | 7.6 fps |
| Pentax K-x | 17 | 4.4 fps |
| Nikon D5000 | 30 | 3.9 fps |
| Panasonic Lumix DMC-GH1 | 5 | 2.8 fps |
Continuous shooting rates are up to 5 fps in high speed mode, and up to 7 fps in speed priority mode. Our studio tests actually got 7.6 fps in speed priority, much better than advertised. The A550 generates that high fps rate in speed priority by establishing exposure and focus for the first shot of any sequence and applying those values to all subsequent shots. The 5 fps rate is made with exposure and focus calculated for each shot.
AF with the A550 was generally quite accurate in good conditions with the spot AF mode set - the wider area AF modes would sometimes hunt a bit before settling down on the AF point, which wasn't necessarily the point intended. There is an AF assist lamp with a range at 200 ISO of up to about 14 feet - it doesn't operate when the camera is set to continuous AF or in Auto AF when the subject is moving.
The A550 flash is listed as having a guide number (GN) of 12 (meters) at 100 ISO, even though the nominal ISO sensitivity for the camera is 200. Flash range at f/5.6 is in the vicinity of about 9 feet, so if you plan to do a lot of shooting with flash at greater distances an external flash would be a good idea - the A550 is equipped with an accessory shoe that can accept a wireless flash. Flash recycle times are given as 4 seconds by Sony, but in practice our flash recycled a bit quicker than that in moderate lighting with a high battery level.
Sony's "SteadyShot" image stabilization system is on by default in the A550, and is of the sensor-shift type. The camera will display a "camera shake" warning on the OVF or monitor if it senses the shooting conditions are beyond the system's ability to stabilize the image. There is also a "camera shake status" indicator to display the relative degree of shake at any particular time - Sony recommends shooting when this indicator is low. Stabilization should be disabled if the camera is mounted on a tripod.
Sony rates the battery in the A550 for approximately 1000 images using the OVF and about half that in live view, according to a CIPA standard that has proven reliable in my experience. The camera displays both a battery "fuel gauge" icon and battery life remaining as a percentage in the upper right of the graphic display on the monitor.
Battery charging is a little convoluted with the A550 - a steady green light on the charger means charging is underway. When the light goes out the battery has a "normal" charge, but it takes another hour after the light goes out for the battery to be "fully" charged. My vote would be Sony have the charger display a flashing green for charging, steady green for the "normal" charge and lights out with the "full" charge.
Lens Performance
The Sony f3.5-5.6/18-55 SAM zoom lens is fairly typical for kit lenses offered on this class of camera. There was some barrel distortion present at the wide end of the zoom, but pincushion was largely absent at the telephoto end. A bit of softness and a tiny amount of vignetting in the corners at wide angle was again balanced by a fairly even performance across the frame at telephoto. Chromic aberration (purple fringing) was present in some high contrast boundary areas, but the defect was virtually impossible to detect at 100% enlargement on our sample shots.
 |  |
Image Quality
When I first shot the A550 and examined the default results at 100% enlargement I had the feeling the images looked just a bit too soft for my taste. I still feel that way, but upon further consideration I can also see where a lot of folks would have no problem with the images as they come right out of the camera, particularly if they never get involved with large prints. At large magnifications I think the A550 needs additional sharpening above the default values to maximize the image quality, but at the smaller end of the spectrum it can be hard to tell a default shot from one sharpened to my liking. Here's a pelican image captured at default settings, and the same image post-processed with added sharpening. If you have a hard time telling the sharpened shot from the default at the small size you're not alone - I can't either.
Default
Sharp
At any rate, the A550 has contrast, saturation, and sharpening adjustments available in the creative style palette that should be more than adequate to produce results out of the camera to please just about anybody. Here's a shot of Bandit with both contrast and sharpness set to the maximum, which seems to be more than enough.
The downside to this is the settings are available in the manual and semi-automatic modes - folks shooting full auto or the scene modes will have to post process if images produced in these modes don't meet their expectations.
Aside from sharpness, default images out of the A550 were generally accurate with regard to color fidelity.
The A550 is equipped with a "smart teleconverter" offering 1.4 and 2X multiplication factors - the feature downsizes image resolution by making use of smaller portions of the sensor to obtain the magnification factor. Here are shots at 55mm, and with the 1.4 and 2X converters enabled.
55mm
1.4X Teleconverter
2.0 Teleconverter
File sizes are drastically reduced, but the extra magnification can extend the reach of that kit lens just a bit further.
The A550 offers multi-segment, center-weighted and spot metering exposure options, with multi-segment being the default. This method worked well in most situations, but could lose some highlights in high contrast conditions. The creative style color options give the user six color options: standard (the default), vivid, portrait, landscape, sunset and B/W. Here are examples of each.
 Standard |  Vivid |
 Portrait |  Landscape |
 Sunset |  Black and White |
One of the major features of the A550 is the existence of two distinct methods for managing dynamic range in image captures. The first is the dynamic range optimizer (DRO), which has automatic and five user established levels of brightness correction available. Here are shots with the DRO off, in auto mode, and at level 3 and 5. In practice, reviewing histograms indicated that the auto mode produced a level of brightness that seemed to fall between levels 1 and 2 of the user established settings.
 DRO Off |  DRO Auto |
 DRO 3 |  DRO 5 |
The second method is auto high dynamic range, which captures two quick images emphasizing highlight detail on one and shadow detail on the other, then merging the two captures into a single image. The level of exposure can be calculated automatically or set by the user within a range of 1 to 3 EV in .5 EV increments. This method is recommended for still subjects only and requires shooting discipline to remain still while the camera takes two captures. Here are examples of HDR auto, and levels 1, 2 and 3.
 HDR Auto |  HDR +1 |
 HDR +2 |  HDR +3 |
Auto white balance worked fairly well with a multitude of light sources, but shot warm under incandescent in the studio and a bit cool under some very dark cloudy conditions. Lighter cloudy days were OK. In addition to auto the camera offers daylight, shade, cloudy, incandescent, fluorescent, flash and temperature settings; all but the temperature option have varying degrees of adjustment possible, while temperature can be set from 2500 to 9900 degrees Kelvin (K) in 100 degree increments.
Auto White Balance, 3200k incandescent light
With some of Sony's newest technological hardware onboard I was hopeful the A550 might provide some outstanding noise performance. The A550 does a decent job and is competitive in the class, but to my eye it didn't beat the competition and might be a tiny bit behind at least two of the other brands in the class as ISOs push out to 800 and above.
 ISO 200 |  ISO 200, 100% crop |
 ISO 400 |  ISO 400, 100% crop |
 ISO 800 |  ISO 800, 100% crop |
 ISO 1600 |  ISO 1600, 100% crop |
 ISO 3200 |  ISO 3200, 100% crop |
 ISO 6400 |  ISO 6400, 100% crop |
 ISO 12800 |  ISO 12800, 100% crop |
ISO 200 and 400 are both quite clean and hard to tell apart, with some slight noise appearing at 800 and increasing a bit at 1600. Nonetheless, the A550 is pretty good through 1600 with things starting to degrade faster at 3200 and up. ISO 6400 and 12800 are there if you need them, but those levels are for cases where nothing else will work.
Additional Sample Images
With the exception of the hummingbird shot, all of the miscellaneous images were posted as they came out of the camera. The hummingbird, originally shot at default settings, was post processed for sharpness only.
 |  |
 |  |
 |  |
 CONCLUSIONS No matter which end of the spectrum they're at, any user will appreciate a quick start up and responsive shutter along with a reasonably quick AF system. For those who just can't divorce themselves from using the monitor for image capture, the A550 offers a live view system that's quick and easy to use. Image and color quality is good, and if shooting in the manual or semi-automatic modes there are substantial user established settings available to tailor output to virtually any taste. Noise performance is about par for the class, the plastic on the body might look a bit cheap for the price point and the battery charging cycle is odd, but these are really minor gripes for a camera that goes about its business in a very capable manner. Pros:
Cons:
|
0 ความคิดเห็น:
Post a Comment