Photography Digest

The Sony DSLR-A580 was announced, together with the SLT-A55, in August 2010. In Sony's slightly convoluted DSLR line-up it is firmly located in the mid-level bracket, competing with cameras such as the Canon EOS 600D/Rebel T3i and Nikon D5100.
Both the A580 and the A55 continue Sony's tradition of designing cameras which are 'a bit different' from the rest. This is especially true for the A55 which, with its translucent fixed mirror and electronic viewfinder, can't even technically be called an SLR. The subject of our review though, the DSLR-A580, comes with a moving mirror and is therefore more of a 'traditional' SLR, but its second live view mode still sets it apart from the more conventional competitors. Like its predecessor, the DSLR-A550, the camera uses a small secondary sensor in the viewfinder to provide live view with fast phase-detection AF, but can also utilize the slower but higher-resolution main-sensor live view system used by all other manufacturers, albeit only with very slow contrast-detect AF.
The unusual live view concept is not the only element that the new model has taken over from its predecessor. The A580 body is, apart from some minor changes to the button layout and the color of the top plate (black vs gray), visually indistinguishable from the A550. Inside the body shell it is a different story. The A550 captures its images on the same 16.2MP CMOS sensor that we were pretty impressed with in our SLT-A55 review. With the new sensor the camera also gains a few new features, such as 1080p full-HD video, a sweep-panorama mode and a multi-frame ISO 25600 mode, all of which are available on the A-55 as well.
In essence the DSLR-A580 offers an A55 image pipeline in an A550 body which makes it, at least on paper, an ideal solution for those who like the new Sony 16.2 MP sensor's image output but prefer a more traditional DSLR design with an optical viewfinder over the A55's EVF and translucent mirror.

The two-mode live view

One of the most notable features of the new camera is one that has been taken over from its predecessor - the second live view mode. The A580 sports a small secondary sensor in the viewfinder to provide live view with fast phase-detection AF, but can also utilize the slower but higher-resolution main-sensor live view system used by all other manufacturers. Contrast detect AF is now available in this latter mode which as a consequence is now called 'Focus Check Live View' (as opposed to MF Check Live View).

Live view	Optical Viewfinder	Focus Check Live view
Roll your mouse over the above images to see how the light path is redirected between the viewfinder and live view sensor. With the mirror in the up position, the Focus Check mode does not direct any light to the AF sensor at the bottom of the camera and hence can only focus using the slower contrast-detect method.

Sony A580 - key specifications

• 16.2MP (effective) APS HD CMOS sensor
• Maximum ISO 12,800 (with a quasi-ISO 25,600 'Multi-frame NR' option)
• 15-point AF system with 3 cross-type AF points
• Contrast-detect AF in focus check live view mode
• Electronic level in LCD with pitch/roll indicator
• Switchable Memory Stick/SD card slots (only one in use at any time)
• Up to 7fps continuous shooting rate
• 1080p AVCHD movie mode with continuous AF
• Hinged 3 inch LCD with 921k dots
• 3D sweep-panorama
• Socket for external microphone
• Face-detection AF (focus via nearest phase-detection AF point)

At the same time as the DSLR-A580 Sony also launched the sister model A560. The only difference between the two models is the imaging sensor. The A560 captures its images on a 14.2 MP CMOS sensor instead of the A580's 16.2 MP.


Original Article:www.dpreview.com