While the A57 continues to use the same 1.4 million dot LCD panel as the A55 for its electronic viewfinder, it features revised optics that allow use of a larger area of the panel. As such, the A57 offers two viewfinder modes, a 'Maximum Magnification' option that uses the full 800 x 600 resolution display and a 'Standard' mode that uses a smaller subset of the screen in order to provide a longer eye-point (the distance from which the entire display can be seen) - potentially a benefit for those wearing glasses.
The LCD itself is a field-sequential device - it shows red, then green, then blue information in rapid succession, rather than being able to show them all at the same time. The result is that you may see 'rainbow' flashes of these primary colors (tearing) when looking quickly around the frame or blinking. We suspect some users will find this less disconcerting than others, but it's a shame that the A57 lacks the far superior OLED EVF found in higher-end models like the A65 and A77.
One figure hidden away in every SLR's spec is the size of the viewfinder (often in a format that makes comparison between competing models impossible). The size of the viewfinder is a key factor in usability - the bigger it is, the easier it is to frame and focus your shots, and the more enjoyable and involving process it is.
Because of the way viewfinders are measured (using a fixed lens, rather than a lens of equivalent magnification), you also need to take the sensor size into account, so the numbers in the diagram below are the manufacturer's specified magnifications divided by the respective 'crop factors'.
Sony's figure for the Maximum Magnification mode is a robust 1.04x magnification. As with previous SLT models, the A57 has a significant edge over most conventional DSLRs, regardless of class. You can see in the graphic above that the A57's viewfinder is not far off from that of a full-frame camera like the Canon EOS 1D X.
The A57's EVF is the same size as the unit on the A55. An eye sensor placed directly above it allows for automatic switching between the EVF and rear LCD panel.
Like its predecessor, the A57 features a fully articulated (not just fold down/out) LCD screen, which hinges along its lower edge, and can be completely reversed to protect the screen when the camera isn't being used.
The built-in flash is the same unit as on the SLT-A65. It has a guide number (GN) of 10 at ISO 100 and covers a wide-angle up to 18mm.
The A57 gains a stereo microphone that is built into the camera's top plate, between the hot shoe and flash housing.
As is common for Sony, a connector for an external microphone is provided.
Beneath the mic socket is a rubber flap containing HDMI and USB ports. A DC connector is housed beneath the flap at left. Above this the A57 also has a terminal (not pictured) for the optional RM- L1AM remote.
You can also see three holes, behind which lies the camera's monoaural speaker for video playback.
As on previous SLT models the SD-card compartment is hidden under a door on the camera's right side.
The A57's 7.V, 11.8Wh NP-FM500H lithium-ion battery is the same one found in the A65 as well as the enthusiast models A77 and A700; a notable improvement over the A55's smaller variant.
Sony states the battery life as approximately 550 shots with the EVF, 590 shots using the rear LCD and 180 min of video shooting (CIPA-standard).