Sony Alpha A550

Sharpness

Image sharpness holds up reasonably well at all tested focal lengths, with the only major trouble occurring at very high aperture settings. The top results in our tests were at the 35mm focal length, with a maximum horizontal resolution reading of1881 lw/ph and a maximum vertical reading of 1734. More on how we test sharpness.

Image Sharpness and Chromatic Aberration

Focal Length:

18.0mm

35.0mm

55.0mm

Click blue squares to change sample crops below
f/3.9 f/9 f/22
f/5 f/11 f/29
f/5.6 f/14 f/36

Image Stabilization (5.50)

Like other Sony SLRs, the A550 provides in-camera image stabilization, so any lens can benefit from the technology. However, in our tests using the kit 18-55mm lens at its full telephoto length, we found the IS system provided minimal improvements. We test image stabilization based on the improvements in image resolution produced with the system turned on versus shots taken with the system off. The camera is mounted in a custom-built, computer-controlled rig, shooting separately in both horizontal and vertical orientation and with low and high levels of shake.

Measured at low shake levels, roughly what you’d expect from someone standing still and holding the camera with both hands, we found slight improvements when shooting at shutter speeds below 1/30 second.

Cranking the shake up to a higher level, which you might experience when shooting while moving quickly, the IS system actually produces poorer horizontal shake results at high shutter speeds. There is a consistent, modest blur reduction when shaking the camera vertically, which becomes significant as we move to the slowest shutter speeds.

The A550’s image stabilization performance is about even with the lens-based stabilization used in the Nikon D5000, a bit better than we found with the Panasonic GF1, but none of these cameras came close to the improvement we measured using the Olympus in-camera image stabilization.

Sony includes an interesting on-screen SteadyShot scale in the lower left corner of the LCD when shooting in modes where shutter speed is set automatically. This five-bar indicator shows the camera shake status; the fewer bars shown, the more likely a shot will be free from blur.

Image Stabilization Comparison Table			Expand
	Low Shake IS Off	Low Shake IS On	High Shake IS Off	High Shake IS On
1/500
1/250
1/125
1/60
1/30
1/15
1/8