Sony A55 Performance

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Sony A55V Performance

Timing and Performance

A mixed bag when it comes to performance, ranging from below average to exceptionally fast.

Startup/Shutdown
Power on to first shot	~0.9 second	Time it takes for camera to turn on and take a shot.
Shutdown	~2.1 seconds	How long it takes to turn off. (Slightly slow, due to dust-removal sensor shake on shutdown.)
Buffer clearing time	18 seconds * after 32 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.
	22 seconds * after 19 RAW frames
	32 seconds * after 18 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 and shutdown times are slower than average for an SLR. Shutdown is slow probably due to sensor cleaning. Buffer clearing times are quite slow, but not surprising considering the deep buffers and large files.

Mode Switching
Play to Record, first shot	~0.6 second	Time until first shot is captured.
Record to Play	~1.1 second	Time to display a large/fine file immediately after capture.
Display recorded image	~0.9 second	Time to display a large/fine file already on the memory card.

Mode switching times are about average for an SLR.

Shutter Response (Lag Time)
Full Autofocus Single Area (center) AF	0.220 second	Time from fully pressing shutter button to image capture (with Sigma70mm f/2.8 prime).
Full Autofocus Wide Area AF	0.218 second	Time from fully pressing shutter button to image capture (with Sigma70mm f/2.8 prime).
Full Autofocus Single Area AF, Flash enabled	0.475 second	Time from fully pressing shutter button to image capture (with Sigma70mm f/2.8 prime), Auto Flash enabled.
Pre-focused	0.103 second	Time to capture, after half-pressing and holding shutter button.
Continuous AF	0.215 second	This mode usually shows no speed increase with our static subject; we have no way to measure performance with moving subjects.
Manual focus	0.214 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."

Looking at the Sony A55V's ability to determine that it's properly focused when shooting the same target multiple times, its speed is about average for a consumer SLR. The SLT-A55V required 0.22 second for full AF using the center focus point. This decreased slightly to 0.218 second in wide-area AF mode. Enabling the flash raised the lag to 0475 second, to account for the flash exposure preflashes. Continuous autofocus mode lag time was 0.215 second and manual focus was only slightly faster at about 0.214 second. When prefocused, shutter lag was 0.103 second which is good but a bit slower than average for an SLR these days, and somewhat of a surprise for a camera that doesn't need to wait for a mirror to be raised before taking the shot. Keep in mind that the shutter is normally open though, so it needs to be closed and re-opened to take the exposure.

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	0.52 second	Time per shot, averaged over 20+ shots.
Single Shot mode RAW	0.52 second	Time per shot, averaged over 28 shots.
Single Shot mode RAW + JPEG	0.51 second	Time per shot, averaged over 23 shots.
Early shutter penalty?	No	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	0.17 second (6.02 frames per second); 39 frames total; 15 seconds to clear	Time per shot, averaged over buffer depth of 39 shots.
Speed Priority Continuous mode Large Fine JPEG	0.11 second (9.04 frames per second); 32 frames total; 18 seconds to clear	Time per shot, averaged over buffer depth of 32 shots, then slows to an average of 0.64s or 1.57 fps.
Speed Priority Continuous mode RAW	0.10 second (10.17 frames per second); 19 frames total; 22 seconds to clear	Time per shot, averaged over buffer depth of 19 shots, then slows to an average of 1.25s or 0.80 fps.
Speed Priority Continuous mode RAW + JPEG	0.10 second (10.18 frames per second); 18 frames total; 32 seconds to clear	Time per shot, averaged over buffer depth of 18 shots, then slows to an average of 1.87s or 0.53 fps.
Flash recycling	3.7 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 about average for an SLR, at about 0.5 second per frame for any quality. Continuous mode speeds were excellent though, especially for a non-pro SLR, at about 6 frames-per-second for large/fine JPEGs in Continuous Hi mode. Speed Priority mode is exceptionally fast for any SLR at 9 frames-per-second for large/fine JPEGs and 10.2 frames-per-second for RAW or RAW + JPEG. If we ignore a consistent hiccup we encountered at the 16th frame in large/fine JPEG mode, it too achieved 10 frames-per-second. Remarkable.

Buffer depths are very good for a consumer model, at 39 frames for large/fine JPEG frames with a fast SDHC card. We didn't test with a Memory Stick. Buffer depths are generally a bit lower in Speed Priority mode, at 32 large/fine JPEGs, 19 RAW and 18 RAW + JPEG frames, but still very good. The flash takes 3.7 seconds to recharge after a full-power shot, which is good.

Download speed
Windows Computer, USB 2.0	15,408 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 SLT-A55V's performance ranges from below average (startup and shutdown), to average (mode switching, autofocus, single-shot cycle times), to much better than average (burst speed and buffer depth). Its super fast burst speed should come in very handy for sports and active kids.

Battery and Storage Capacity

Battery
Below average battery life compared to a traditional SLR with optical viewfinder, but decent battery life for an interchangeable lens camera with EVF.

Operating Mode	Number of Shots (SLT-A55V / SLT-A55)
Electronic Viewfinder, (CIPA standard)	330 / 350
Live View LCD, (CIPA standard)	380 / 390

The Sony A55 uses a custom rechargeable lithium-ion battery for power, and ships with a charger. Battery life is a below average compared to an SLR using an optical viewfinder, but just about average compared to an SLD with electronic viewfinder. We recommend you pick up a spare battery and keep it freshly charged and on-hand for extended outings or shooting video.

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 A55 accepts SD (including SDHC and SDXC types) or Memory Stick Pro Duo memory cards. No card is included with the camera.

Image Capacity vs Resolution/Quality 1GB SD Memory Card		Fine	Normal	RAW	RAW + JPEG
4,912 x 3,264	Images (Avg size)	144 7.1 MB	205 5.0 MB	58 17.4 MB	41 24.7 MB
4,912 x 3,264	Approx. Comp.	7:1	10:1	1.4:1	-
3,568 x 2,368	Images (Avg size)	233 4.4 MB	325 3.2 MB	-	-
3,568 x 2,368	Approx. Comp.	6:1	8:1	-	-
2,448x 1,624	Images (Avg size)	367 2.8 MB	468 2.2 MB	-	-
2,448x 1,624	Approx. Comp.	4:1	6:1	-	-

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 and while shooting video. (Check the shopping link above, cards are really cheap these days, so no reason to skimp.)