Sony Alpha SLT-A55V: Performance

by Jim Keenan Reads (814)
Editor's Rating
8.40

TG Ratings Breakdown

    • Image/Video Quality
    • 8
    • Features
    • 9
    • Design / Ease of Use
    • 8
    • Performance
    • 8
    • Expandability
    • 9
    • Total Score:
    • 8.40
    • Rating 1 to 10, top score 10

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).


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