Sony SLT-A57 In-Depth Review
Body & Design (continued)
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.