A free firmware upgrade refines shooting responses and creative options with the α900 and α850 35mm full-frame DSLR cameras by Sony.

Sony advises all new and existing customers to install the upgrade that?s available for download from the 'Support' area of the Sony web site.

Autofocus is quicker and more responsive than ever, thanks to improved AF motor control and smarter distance detection of out-of-focus objects.

Creative options are extended by a broadened range of exposure value (EV) compensation settings, now increased from ±3EV to ±5EV. Selected compensation value is displayed in the navigation display on the main LCD screen of both cameras. This boosted EV compensation range gives extra eadroom when composing extremely high- or low-key images.

Exposure bracketing range has also been increased from a maximum of 4.0EV (three shots at -2EV, 0EV, +2EV) to a maximum of 6.0EV (-3EV, 0EV, +3EV). This wider range gives added flexibility when capturing multiple frames at different exposure values - for example when acquiring images for the creation of powerful post-shooting HDR effects.

As a further refinement, a new menu option allows shutter release to be enabled, even when the camera body doesn't detect an attached lens. It's useful for specialist applications such as astrophotography when the camera is attached to a telescope.

The latest firmware upgrade by Sony for registered α900 and α850 DSLR customers is available from http://support.sony-europe.com/dime/DSLR/dslr.aspx.