Sigma has acknowledged that Pentax users are suffering from blurred images when the company’s 17-70mm f/2.8-4 DC Macro HSM Contemporary lens is used on Pentax DSLR bodies with in-camera image stabilization activated. To rectify the issue, the lens manufacturer has promised a firmware update for the lens, but it hasn’t specified when it will be released. Owners of the Sigma USB Dock will be able to update the firmware themselves via Sigma Optimization Pro 1.2, but those without the dock will need to take their lens to an authorized distributor.

The problem seems to be a result of the lens not passing on focal length information to the camera’s Shake Reduction system accurately, so that when the lens is used at wider focal lengths the camera works to stabilize for a longer focal length – thus introducing blur via the over-active sensor movement.

Sigma points out that lenses being shipped from the factory now have been corrected.

Users of the 150-600mm f/5-6.3 DG OS HSM Sports lens in Sigma, Canon and Nikon mounts can also take advantage of new firmware that promises to improve Optical Stabilization performance when panning. The lens’ OS mode 2 will now add camera shake compensation in vertical and diagonal directions, as well as the standard horizontal compensation.

The firmware can be accessed on Sigma’s global website.