Sony A77 Exposure
Sony Alpha A77 Exposure Options
The Sony A77 offers all the same exposure options you'd expect in a mid-range SLR camera, plus a few Sony-specific options. Available exposure modes include Program AE, Aperture Priority, Shutter Priority, and Manual modes, with shutter speeds from 1/8,000 to 30 seconds, as well as a Bulb setting available in Manual mode only, for longer exposures. The x-sync speed for flash photography is 1/250 second. A fully automatic mode places the camera in control of almost all functions, to try to deliver optimum results under a wide range of conditions. Another mode called Auto+ is similar to standard Auto, but has scene recognition that allows it to automatically select one of a dozen different scene types, some of which can't be directly accessed from the Scene mode. Basic options such as exposure compensation aren't available to the photographer in either of the Auto modes, but the A77 will still allow you to select from a subset of drive modes and flash modes, lock exposure with the AEL button, focus manually or automatically, and enable or disable the face detection and smile shutter functions.
The Sony A77's Mode dial also includes a Scene position, offering access to including Portrait, Sports Action, Macro, Landscape, Sunset, Night Scene, Hand-held Twilight, and Night Portrait. There's also a separate Sweep Panorama mode that captures and stitches a multi-image panorama with a single press of the shutter button, and merits its own position on the dial. So does a 3D Sweep Panorama mode, which operates similarly, but simulates a 3D effect with some clever maths. A Continuous Advance Priority AE mode locks the lens aperture at either F3.5, or the maximum aperture of the lens, whichever is smaller, removing the delay required to set and reset the aperture to allow focusing between shots. This enables the camera's fastest burst-shooting performance of 11.6 frames per second, according to our in-house testing. Finally, there's both a Movie mode that enables capture of videos with manual control over exposure variables, and a Memory Recall mode that allows three different groups of camera settings to be saved for later recall.
The Sony A77 offers an optional live histogram function in all operating modes. Located near the bottom right corner of the LCD panel or electronic viewfinder display, it's rather small, and offers only a luminance readout rather than a full RGBY histogram, but it's still very useful for ensuring your exposures are correct. Another feature that's rather more common, but still very welcome, is the exposure display when the camera is in Manual exposure mode. This shows the amount the camera thinks an image will be over- or underexposed within a range of +/-2.0EV, based on the settings you have selected, to help you find the best exposure for the subject. (Beyond the 2.0EV range, arrows on either end of the scale blink in the viewfinder, and the value blinks on the rear-panel LCD, to emphasise that the metering system's limit has been reached.) Together, the live histogram and exposure display make it relatively easy to get suitable exposures even when shooting manually.
Sony A77 Face Detection / Recognition
Sony A77 ISO Range
In Program and Priority modes, but not in Manual mode, an Auto ISO mode is available, and in Auto, Auto+, Scene, and Sweep Panorama modes, it's the only option. The upper and lower limits for the function can be manually set within a range of ISO 100 to 12,800 in all modes except Movie (which has an upper limit of ISO 1,600), and those that require Auto ISO (which leave the range in the camera's control).
In addition, the Sony A77 offers a Multi-Frame NR function, which combines multiple shots into a single output image, in a similar manner to the Hand-held Twilight scene mode. The difference between the two functions is that Multi-Frame NR allows direct control over ISO sensitivity. Multi-Frame NR is available only in the Program, Priority, and Manual modes, and is accessed from the ISO sensitivity dialog. When using Multi-Frame NR, the maximum ISO sensitivity limit is expanded to ISO 25,600 equivalent.
Sony A77 Noise Reduction
A separate Long Shutter noise reduction On / Off setting is available in Program, Priority, and Manual modes, for dark frame subtraction when shooting exposures of one second or longer. If enabled, this approximately doubles the exposure time for each shot, allowing the second dark frame exposure to be captured with the shutter closed.
Sony A77 White Balance Options
In all of the preset white balance modes, you can fine-tune the color by pressing the left / right arrow keys on the four-way controller while in the White Balance menu. Blue / red adjustment is possible within a range of -3 to +3 arbitrary units for all but the fluorescent mode, which offers only a -1 to +2 unit range. In Kelvin white balance mode, there's also a color filter function which offers a magenta - green filter within a fairly wide range of -9 to +9 arbitrary units.
Custom white balance is set by selecting Custom Setup from the white balance menu, and pointing the camera at a neutral white or grey card under the lighting you'll be shooting in, filling a frame in the center of the display with the reference target, then pressing the Shutter button.
In addition, the Sony A77 can bracket white balance using the White Balance Bracketing (BRK WB) option in the Drive Mode menu. For each shutter release, the A77 records three separate image files, varying only the white balance between each image. Two step sizes are available -- 10 mireds when using the BRK WB Lo setting, and 20 mired steps with the BRK WB Hi setting.
Sony A77 Metering Options
By default, you can lock an exposure reading separately from autofocus lock by pressing and holding the AEL button. Alternatively, the AEL button behaviour can be changed so that pressing and releasing the button will set and release the autoexposure lock on subsequent presses.
Sony A77 Exposure Compensation & Bracketing
The Sony A77's Exposure Compensation adjustment increases or reduces the overall exposure from -5 to +5 exposure values (EV) in one-third stop increments, and like White Balance, the effect of Exposure Compensation is simulated on the preview image if possible. In addition, the A77 offers -3 to +3 EV of flash exposure compensation, in 1/3 EV increments, set through the Function menu. A Continuous Bracketing feature captures multiple shots with different exposures. See the Drive Mode section on Continuous Bracketing below for more details.
Sony A77 DRO / HDR
The DRO and HDR modes can't be used together, and each brings its own set of advantages and disadvantages. Since DRO only works from a single shot, it must operate entirely within the dynamic range available from the image sensor, where the HDR mode is able to capture a significantly greater dynamic range than is possible in one shot. Since DRO is effectively amplifying the signal in shadow areas of the image, it also brings increased noise (or increased noise reduction) in the shadows. HDR mode, meanwhile, is suitable only for relatively static subjects, given that it requires multiple exposures. Thanks to microalignment capability, Sony's HDR mode is at least able to deal with the slight changes in framing caused by shooting handheld, but subject motion or camera shake will likely cause unacceptable artifacts in HDR images.
Both DRO and HDR can be disabled altogether if desired, although the default on the A77 is for DRO Auto mode to be left enabled.
Sony A77 Hand-held Twilight
The Sony A77's implementation of Hand-held Twilight does have one important difference from the similar mode found on its point-and-shoot siblings. Where the existing cameras have been able to use an electronic shutter to capture the source images, the A77 must instead rely on its physical shutter. The A77's mirror slap isn't the quietest we've heard, and with six frames captured in a rapid burst, its Hand-held Twilight mode can have bystanders turning around in expectation of seeing a paparazzo in their midst. ;-)
Sony A77 Sweep Panorama
Again, since there's no electronic shutter to rely on, the mirror slap noise means you won't be catching anybody by surprise, That said, the feature functions pretty well if you've a reasonably steady hand, and your subject matter isn't too close to the camera. If your subject matter is too close to the camera, or your panning isn't smooth and straight, the seams between separate images can become fairly noticeable. Focus and exposure are locked from the first frame of the panorama, so you'll want to pick your starting point carefully. From there, you can pan left, right, up, or down, simply sweeping the camera across your subject matter after pressing the shutter button.
Two panorama sizes are available -- standard, or wide. Standard horizontal panoramas are limited to 15 megapixels, and vertical panoramas to 8.4 megapixels. In Wide mode, horizontal panoramas are 23 megapixels, and vertical panoramas are 12 megapixels. For 3D mode, only horizontal panoramas are possible, with the standard size providing 5.3 megapixel resolution, and the wide size offering 7.7 megapixels. There's also a 1,920 x 1,080 pixel mode designed to match the resolution of a Full HD display, available only for 3D panoramas.
A darkened mask over the left third of the LCD display shows an area of the frame that won't be included in the final output image, and an on-screen message warns you if the Alpha A77 wasn't able to track your panning, prompting you to recapture the panorama. (Depending on how much was captured, the A77 sometimes retains a partial panorama with the uncaptured portion of the image left as a flat grey.)
Sony A77 Drive Modes
The Sony A77 offers a variety of shooting modes, accessed via a dedicated Drive Mode button on the camera's top deck, or through the Drive Mode option under the Function menu. Options vary depending on the shooting mode, but include Single Shot Advance, two Continuous Advance modes, two Self Timer modes, Continuous Bracket, Single Bracket, White Balance Bracket, DRO Bracket, and Remote Commander. Single-shot, as you'd expect, captures a single image with each press of the shutter button. Continuous Advance captures images at either eight frames per second in Hi mode, or three frames per second in Lo mode, while the shutter button is held down. As many as 13-15 shots can be captured in a burst depending upon file type, adjusting focus and exposure between shots as necessary.
The Self-timer modes offers a choice of either two or ten second timers. The Bracket modes let you take a sequence of three or five shots with either 0.3, 0.5, or 0.7 EV exposure variation steps, or three shots with 2.0 or 3.0 EV steps. The sequence order is to shoot the metered exposure first, followed by the underexposed and overexposed frames. The difference between the two modes is that Continuous Bracket will capture all the necessary frames as fast as possible while the shutter button is held down, while Single Bracket requires you to full press the shutter button once per frame. White Balance Bracket captures three images with varied white balance settings, as described in the white balance section of this page. DRO Bracket offers two choices: Low captures three images at DRO levels 1 to 3, and High at levels 1, 3, and 5. Finally, Remote Commander mode configures the A77 to capture images as directed by the optional RMT-DSLR1 wireless remote control, which communicates with the camera via an infrared receiver hidden behind a shiny plastic trim piece in the top of the hand grip's front surface.
Finally, Continuous Advance Priority AE mode is accessed via a dedicated Mode dial position, and locks the lens aperture at either F3.5 or the maximum aperture of the lens, whichever is smaller, removing the delay required to set and reset the aperture to allow focusing between shots. This enables the camera's fastest burst-shooting performance of 11.6 frames per second, according to our in-house testing.
Sony A77 Creative Styles
Sony A77 Geotagging
Finally, the Sony A77 allows geotagging of images and movies at the time of capture. This allows them to be tagged with information regarding capture location, including latitude, longitude, altitude, receiver speed and direction, and the GPS time stamp. Movies are only tagged with information regarding the location at the start of the clip. Accuracy will vary depending on the number of satellites in view at a particular time and location. The initial GPS lock can take several minutes to achieve, if the camera hasn't been used recently, although again this can depend on environmental conditions, as well as the number and position of satellites in view. It's possible to reduce this time by uploading GPS-assist data to the A77 body using Sony's provided Picture Motion Browser software, which can greatly reduce the length of time required to obtain a GPS lock. This process has to be repeated roughly once per month, as the assist data is only good for so long. You can also set the A77 to automatically update its clock based on the time provided by GPS satellites.
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Sony Alpha SLT-A77 Photo Gallery .
Not sure which camera to buy? Let your eyes be the ultimate judge! Visit our Comparometer(tm) to compare images from the Sony Alpha SLT-A77 with those from other cameras you may be considering. The proof is in the pictures, so let your own eyes decide which you like best!