Sigma has a new version of its 17-50mm F2.8 lens for the Sony Alpha and Pentax K-mount ge lwa site. The company has for both cameraplatforms the optical image stabilization removed. The retail price however remained the same.
Sony and Pentax both use of sensor-shift image stabilization in the camera body to reduce unwanted vibrations. For Sigma is that a reason to own the OS image stabilization system is the newest 17-50mm F2.8-lens to leave out. Optical image stabilization is, however, particularly at longer focal lengths is more effective than sensor-shift image stabilization.
Given the specifications of the new 17-50mm F2.8 EX DC HSM lens it seems that there is, except for the removal of the optical image stabilization, no important changes have taken place. So, the lens is still constructed of 17 lens elements in 13 groups, includes the aperture consists of seven rounded blades and a maximum magnification ratio of 1:5.
On a number of forums sounds a lot of criticism on the new lens. Sigma has decided the price of the new lens to remain the same to that of the current models, despite the removal of OS. The current lens with optical image stabilization for the Sony Alpha and Pentax K-mount will no longer be fed.
