Sony DSLR-A580 Live View

Sony A580 Live View

Like most SLRs these days, the Sony A580 offers the ability to frame images not only through its optical viewfinder, but when in live view mode, also on its rear-panel LCD monitor. As in several of Sony's past models, the live view functionality of the Alpha A580 is unusual in that it offers two operating methods. The default live view mode in the A580 derives its image from a secondary sensor in the viewfinder assembly, an uncommon technique that allows the camera's phase detection autofocus system to operate without interrupting the live view feed. This method also has the advantage of not warming the main image sensor during live view operation, which could raise noise levels in the final image -- especially during long exposures. The approach has a couple of drawbacks, though. Because the secondary sensor is relatively small compared to the primary image sensor, the live view feed can be noisy in low light. A combination of the secondary sensor's low resolution and difficulties in precisely matching the point of focus between main and secondary sensors also conspire to make it relatively less useful for manual focus adjustment, unless you've a generous depth of field to work with. It also has rather looser frame coverage, as detailed on the Optics tab.

For that reason, Sony offers a secondary live view mode, dubbed Focus Check LV, which uses the more traditional live view method found in most DSLRs, with the live view feed derived from the main image sensor. This mode offers much higher resolution, and since the primary image sensor is being used to frame the image, you can confirm the point of focus with confidence. (To make things even easier, the A580 provides a focus assist zoom function that allows any area of the image frame to be enlarged by 7.5x or 15x, making it really easy to confirm the precise point of focus -- at least, if your subject isn't moving too much.) As with most DSLRs offering live view, the A580 doesn't allow phase detection autofocusing in Focus Check LV mode without a brief interruption to the live view feed, during which time the reflex mirror is dropped to allow light to reach the dedicated AF sensor, then raised again to resume the live view feed. Unlike in past Sony cameras, this mode now also offers contrast detection autofocus capability, which is slower than phase detection autofocus, but doesn't interrupt the live view feed, and can potentially offer greater accuracy (as well as the ability to focus anywhere within the image frame) when shooting relatively static subjects.

In both the traditional and Focus Check live view modes, the Sony A580 also offers a face detection function, capable of identifying the locations of up to eight faces in the image frame. Detected faces are identified with a white frame, which turns orange when the camera determines that it can attempt to focus on a particular face. When focus is locked, the frame turns green, letting you see which subjects were given priority by the camera, when setting focus and exposure. Curiously, when in Focus Check LV mode, the face detection function is only available when using phase detection autofocusing, but not with contrast detection. This of course means that the A580 can only focus on detected faces if they fall under one of the fixed points on the autofocus sensor, perhaps robbing the function of a little versatility. (Some competing cameras offer face detection with contrast detect autofocus, allowing the camera to handle focusing on subjects located anywhere within the image frame.)

As you change exposure variables in either mode, the Sony A580 updates its preview display to reflect what the captured image will look like, also known as "exposure simulation." In addition, the Focus Check LV mode allows preview of depth of field and exposure simultaneously, as the camera stops down its lens aperture to the selected value while a dedicated button is held in on the front panel. The Live View / OVF switch on the A580's top deck is used to enable or disable Live View mode, while Focus Check LV mode is activated with an adjacent, dedicated button. The camera needn't be placed into Live View mode before Focus Check LV can be initiated, as the button also functions when the camera is currently in OVF mode. Live view is available in all shooting modes.

The Sony A580's live view mode feature set is comprehensive, and the display offers a lot of information such as current settings, exposure, and composition aids (shown in the illustration below, courtesy of Sony USA). Allowing quick access to camera settings, the Sony A580's Function Menu is available in live view shooting, with the live view image shown in the background of the menu so that you can keep tabs on your subject. Text in the menu is in white with a fine black outline, ensuring it remains readable against both light and dark backgrounds. The selection of options in the Function menu is identical to that for non-live view shooting, and is detailed on the Modes & Menus page.

You can enable one of three different overlays, each of which applies only when framing images in Focus Check LV mode, and/or when automatically reviewing images after capture. The three grids all include four marks that show the outer corners of the area that will be captured in movie mode, along with one of three grid overlay types. Rule of 3rds Grid overlays a 3x3 grid which matches the rule of thirds layout, with the other columns being wider than the central one. Square Grid overlays a 6x4 grid, and oddly, the grid isn't comprised of squares, but of rectangles that are taller than they are wide. Finally, Diag. + Square Grid overlays a 4x4 grid whose elements are indeed square, except for the leftmost and rightmost columns, which are rather wider than they are tall. This overlay also includes two 45-degree lines crossing at image center, and not quite reaching as far as the sides of the image frame where they cross the top and bottom.

A nice feature of Sony's implementation for both live view and Focus Check LV is that the camera doesn't immediately stop the live view feed when you enter the camera's menu system, or switch between operating modes. Some rival cameras will immediately terminate the live view stream and drop the camera's mirror in either instance, causing unnecessary wear and tear on the mirror and shutter mechanisms if you were intending to immediately continue live view shooting. You can display either the live view or Focus Check LV image on a TV via the optionally available HDMI cable. The Sony A580 comes equipped with a temperature sensor, and if the internal temperature exceeds an undisclosed threshold, Live View will be disabled to protect internal circuitry from overheating. A high temperature icon is displayed on the LCD monitor to warn the user that image degradation may be occurring, and that the camera may disable Live View until normal operating temperature is restored.

Like a larger version of the optical viewfinder display, the Live View display reports the exposure information along the bottom of the screen. Additional settings and info can be overlaid on top of the live view feed along the left, right, and top of the image. The locations of focus area(s) are indicated in light gray until a lock is achieved, and then the area(s) which locked focus are outlined in green. The amount of information displayed can be varied by pressing the INFO button, toggling through four display modes -- image plus basic exposure information, image plus basic info and either a graphic display or a luminance histogram, and image plus detailed exposure information. The unusual graphic display option allows you to see both shutter speed and aperture represented on gauges, showing their current position relative to the available range for each exposure variable. In Focus Check LV mode, one additional option is added: image plus a dual-axis tilt display reminiscent of an aircraft attitude indicator. Markings on the indicator illuminate in green to show when the camera is level in one or both axes.