Sony DSLR-A550 Review

 
Camera Reviews > Sony Cameras > Sony Alpha i Initial Test

Sony A550 Performance


Timing and Performance

Very good speed overall for a consumer digital SLR.

Startup/Shutdown

Power on
to first shot

~0.5 second

Time it takes for camera to turn on and take a shot.

Shutdown

1.1 seconds

How long it takes to turn off. (Slightly slow, due to dust-removal sensor shake on shutdown.)

Buffer clearing time

9 seconds *
after 22 L/F JPEGs

Worst case buffer clearing time. -- This is the delay after a set of shots before you can remove the card. Some cameras won't shut down until the buffer is cleared.

12 seconds *
after 14 RAW frames
11 seconds *
after 7 RAW + JPEG frames

*Note: Buffer clearing times measured with a SanDisk Extreme III 8GB SDHC memory card. Slower cards will produce correspondingly slower clearing times.

Startup time is about average for an SLR, but shutdown is a little slow (probably due to sensor cleaning). Buffer clearing times are a bit slow, but not surprising considering the relatively deep buffers and large files.

Mode Switching

Play to Record,
first shot

~0.4 second

Time until first shot is captured.

Record to Play

~0.8 second

Time to display a large/fine file immediately after capture.

Display
recorded image

~0.5 second

Time to display a large/fine file already on the memory card.

Mode switching is pretty fast for a consumer SLR.

 

Shutter Response (Lag Time)

Full Autofocus
Single Area (center) AF

0.184 second

Time from fully pressing shutter button to image capture (with Sigma70mm f/2.8 prime).

Full Autofocus
Wide Area AF

0.194 second

Time from fully pressing shutter button to image capture (with Sigma70mm f/2.8 prime).

Full Autofocus
Single Area AF, Flash enabled

0.219 second

Time from fully pressing shutter button to image capture (with Sigma70mm f/2.8 prime), Auto Flash enabled.

Pre-focused

0.074 second

Time to capture, after half-pressing and holding shutter button.

Continuous AF
0.199 second
This mode usually shows no speed increase with our static subject; we have no way to measure performance with moving subjects.
Manual focus
0.178 second
For most cameras, shutter lag is less in manual focus than autofocus, but usually not as fast as when the camera is "pre-focused."
Full Autofocus
Single Area AF
Live View mode
0.188 second

Time from fully pressing shutter button to image capture (with Sigma70mm f/2.8 prime).

Looking at the Sony A550's ability to determine that it's properly focused when shooting the same target multiple times, its speed is faster than average for a consumer model. The A550 required about 0.184 second for full AF using the center focus point. This increased slightly to 0.194 second in wide-area AF mode. Enabling the flash raised the lag to 0.219 second, but that's still pretty fast. Continuous autofocus mode lag time was 0.199 second and manual focus was only slightly faster at about 0.178 second. When prefocused, shutter lag dropped to 0.074 second, which is quite fast.

The nice thing about Sony's "Quick AF" Live View implementation is that shutter lag in Live View mode is just as fast as when using the optical viewfinder (we measured 0.188 second for single-area full AF lag). This is because the second image sensor located in the A550's viewfinder housing alleviates the need for the additional mirror flips required by most other phase-detect Live View implementations. Other phase-detect systems need to drop the mirror, focus, and raise it again to before taking a shot in Live View mode, or employ a slower contrast-detect autofocus method using the main image sensor. Since the image sensor feeding the A550's live preview is located above the mirror, the mirror stays down until the final exposure, exactly as it does in optical viewfinder mode. As noted elsewhere, though, the downside of this type of Live View implementation is lower accuracy for the Quick AF Live View viewfinder display.

To minimize the effect of different lens' focusing speed, we test AF-active shutter lag with the lens already set to the correct focal distance. We also use the same Sigma 70mm f/2.8 macro with every camera (on all platforms except Four Thirds/Micro Four Thirds and Nikon consumer models lacking an in-body focus motor), to further reduce variation, and because our tests showed that focus-determination time with this lens was close to the fastest, across multiple camera bodies from different manufacturers. Being an older design with a non-ultrasonic motor, it wouldn't be the fastest at slewing from one focus setting to another, but that's exactly the reason we measure focus determination speed, which is primarily a function of the camera body, vs focus adjustment speed, which is primarily a function of the lens.

Cycle Time (shot-to-shot)
Single Shot mode
Large Fine JPEG
0.41 second

Time per shot, averaged over 20 shots.

Single Shot mode
RAW

0.41 second

Time per shot, averaged over 19 shots.

Single Shot mode
RAW + JPEG

0.40 second

Time per shot, averaged over 7 shots.

Early shutter
penalty?

No,
(Yes with flash or when buffer is full)

Some cameras refuse to snap another shot if you release and press the shutter too quickly in Single Shot mode, making "No" the preferred answer.

Continuous Hi mode
Large Fine JPEG
0.21 second (4.82 frames per second);
22 frames total;
9 seconds to clear
Time per shot, averaged over buffer depth of 22 shots, then slows to an average of 0.52s or 1.92 fps, with 31% variation in cycle times.

Continuous Hi mode
RAW

0.21 second (4.85 frames per second);
14 frames total;
12 seconds to clear

Time per shot, averaged over buffer depth of 14 shots, then slows to an average of 0.94s or 1.07 fps, with 39% variation in cycle times.

Continuous Hi mode
RAW +
JPEG

0.21 second (4.76 frames per second);
7 frames total;
11 seconds to clear

Time per shot, averaged over buffer depth of 7 shots, then slows to an average of 1.48s or 0.68 fps, with 3.5% variation in cycle times.

Speed Priority
Continuous mode
Large Fine JPEG
0.15 second (6.67 frames per second);
15 frames total;
8 seconds to clear
Time per shot, averaged over buffer depth of 15 shots, then slows to an average of 0.52s or 1.92 fps, with 32% variation in cycle times.

Speed Priority
Continuous mode
RAW

0.15 second (6.67 frames per second);
13 frames total;
12 seconds to clear

Time per shot, averaged over buffer depth of 13 shots, then slows to an average of 0.92s or 1.08 fps, with 6% variation in cycle times.

Speed Priority
Continuous mode
RAW +
JPEG

0.15 second (6.59 frames per second);
7 frames total;
11 seconds to clear

Time per shot, averaged over buffer depth of 7 shots, then slows to an average of 1.47s or 0.68 fps, with 4.2% variation in cycle times.

Continuous Low mode
Large Fine JPEG
0.33 second (3.01 frames per second);
36 frames total;
9 seconds to clear
Time per shot, averaged over buffer depth of 36 shots, then slows to an average of 0.37s or 2.71 fps, with 19% variation in cycle times.

Continuous Low mode
RAW

0.33 second (3.01 frames per second);
17 frames total;
12 seconds to clear

Time per shot, averaged over buffer depth of 17 shots, then slows to an average of 0.92s or 1.09 fps, with 4% variation in cycle times.

Continuous Low mode
RAW +
JPEG

0.34 second (2.98 frames per second);
8 frames total;
11 seconds to clear

Time per shot, averaged over buffer depth of 8 shots, then slows to an average of 1.42s or 0.70 fps, with 2.3% variation in cycle times.

Flash recycling

3.5 seconds

Flash at maximum output.

*Note: Buffer clearing times measured with a SanDisk Extreme III 8GB SDHC memory card. Slower cards will produce correspondingly slower clearing times. Slow cards may also limit length of bursts in continuous mode. ISO sensitivity and other settings such as DRO or NR can also affect cycle times and burst mode performance.

Shot-to-shot cycle times were good for an SLR, at 0.41 second per frame for large/fine JPEGs or RAW files, and 0.40 second for RAW + JPEG frames. Continuous mode speeds are also quite good for a consumer SLR (especially given the large files), at about 4.8 frames-per-second for any quality. Speed Priority mode is exceptionally fast for a consumer model, at 6.7 frames per second, though autofocus and exposure is locked at the first frame of a burst. A Continuous Low mode limits burst speed to about 3 frames per second.

Buffer depths are pretty good for a consumer model, with 22 frames for JPEG frames with a fast card, 14 RAW frames and 7 RAW + JPEG frames. Buffer depths are generally a bit lower in Speed Priority mode, at 15 large/fine JPEGs, 13 RAW and 7 RAW + JPEG frames. In Continuous Low mode, buffer depths increase to 36, 17 and 8 frames respectively. The flash takes 3.5 seconds to recharge after a full-power shot, which is good.

Download speed

Windows Computer, USB 2.0

16,554 KBytes/sec

Typical Values:
Less than 600=USB 1.1;
600-769=USB 2.0 Low;
Above 770=USB 2.0 High

Connected to a computer or printer with USB 2.0, download speeds are very fast; definitely fast enough that you will likely not feel the need for a card reader.

Bottom line, the Sony Alpha 550 is faster than the average consumer SLR in most respects. Startup time is good, mode switching is good, autofocus is faster than average, cycle time is good, and burst mode is very good, especially in Speed Priority mode. Only shut-down and buffer clearing times are slower than average.

Battery and Storage Capacity

Battery
Excellent battery life for a lithium-ion powered SLR.

Operating Mode Number of Shots
Optical Viewfinder,
(CIPA standard)
950
Live View LCD,
(CIPA standard)
480

The Sony Alpha 550 uses a custom rechargeable lithium-ion battery for power, and ships with a charger. Battery life is a well above average when using the optical viewfinder, and quite good in Live View mode. Still, we recommend you pick up a spare battery and keep it freshly charged and on-hand for extended outings.

The table above shows the number of shots the camera is capable of (on either a fresh set of disposable batteries or a fully-charged rechargeable battery as appropriate), based on CIPA battery-life and/or manufacturer standard test conditions.

(Interested readers can find an English translation of the CIPA DC-002 standards document here. (180K PDF document))

Storage
The Sony Alpha A550 accepts SD/SDHC or Memory Stick Pro Duo memory cards, and no card is included with the camera.

Image Capacity vs
Resolution/Quality
1GB SD Memory Card
Fine Normal
RAW
RAW
+
JPEG
4,592 x 3,056
Images
(Avg size)
162
6.3 MB
229
4.5 MB
66
15.4 MB
47
21.8 MB
Approx.
Comp.
7:1 9:1 1.4:1 -
3,344 x 2,224
Images
(Avg size)
258
4.0 MB
353
2.9 MB
- -
Approx.
Comp.
6:1 8:1 - -
2,288x 1,520
Images
(Avg size)
404
2.5 MB
503
2.0 MB
- -
Approx.
Comp.
4:1 5:1 - -

We strongly recommend buying either a large capacity SDHC, or a large capacity Memory Stick Pro Duo card, at least a 2GB card, preferably a 4-8GB one, to give yourself extra space for extended outings. (Check the shopping link above, cards are really cheap these days, so no reason to skimp.)

 

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