Sony Alpha DSLR-A900 Review: Digital Photography Review

Top of camera controls (right)

The majority of the A900's photographic controls are clustered around the top right-hand corner of the body within easy reach of your thumb. We'll look first at those found on the top plate. Here you'll find the shutter release and front control dial plus buttons giving direct access to AE compensation (+/-), White Balance, ISO and Drive mode, plus the new info panel and a little button to illuminate it. Although the layout is clean and functional it's also the one place we really find cause for complaint about the Alpha 900's ergonomics; the ISO button is simply impossible to get to with any finger whilst actually shooting; I'd prefer it to be swapped with the drive button (which I personally rarely use).

Control Dials

Like the Alpha 700, the 900 has two control dials that are used to adjust exposure or settings after a button has been pressed. The "front control dial" is mounted in front of the shutter release button and the "rear control dial" is mounted horizontally on the rear right corner of the camera just under your thumb. The dials are also used to control shutter speeds and apertures, for scrolling images in playback and (if configured to do so) to offer direct, instant AE compensation control.

Buttons (shooting mode)

As mentioned a couple of pages back the A900 offers more than one way to access and control the various options and settings commonly used when taking pictures. The top panel buttons (white balance, AE-C, drive and ISO) offer direct control over settings using a 'hold down the button and turn the dial' process (incidentally you can disable this so pressing any of the top buttons always brings up the 'exclusive' menu for that item.

Button	Action
DRIVE	Drive mode (turn front dial whilst pressed to change setting) • Single frame advance • Continuous advance (turn rear dial to swap between L and H modes) • Self-timer (turn rear dial between 10 or 2 seconds) • Continuous bracketing (press up/down to select exposure step) • Single frame bracketing (press up/down to select exposure step) • White balance bracketing (press up/down to select Hi / Lo step) • Mirror Lockup • DRO bracketing (press up/down to select Hi / Lo step) • Remote control (using supplied wireless remote)
	Exposure compensation / Flash Output control Hold this button and turn the front or rear dial to change the metered exposure using the on-screen scale. Note that the front or rear dial can be set to give direct access to exposure compensation (i.e. without the button held down)
ISO	ISO (turn front dial whilst pressed to change setting) Hold this button and turn the rear dial to change the ISO (sensitivity) setting in 0.3EV steps. Hold this button and turn the front dial to change the ISO (sensitivity) setting in 1EV steps. • Rear Dial values: AUTO, ISO 100, 125, 160, 200, 250, 320, 400, 500, 640, 800, 1000, 1250, 1600, 2000, 2500, 3200, 4000, 5000, 6400* • Front Dial values: AUTO, ISO 100, 200, 400, 800, 1600, 3200, 6400* (*expanded ISO range)
WB	ISO (turn front dial whilst pressed to change setting) Hold this button and turn the front dial to cycle through the various white balance presets and custom modes. Use the rear dial to fine-tune the white balance.
	LCD illumination Illuminates the top LCD panel to aid visibility in low light.
	Front dial Used to change settings and navigate menus, by default also used to select shutter speed in M and S modes and for direct access to AE compensation in all auto modes. The function of the front dial can be customized to a certain degree. The front dial is also used for scrolling through images in playback mode.