Sony DSLR users may, or may not know they don’t get any visual benefit from sensor-shift type image stabilization, that is, the Sony SteadyShot stabilization only begins its job once the mirror is up and out of the way, after you press the shutter button. Canon and Nikon DSLR users have grown accustomed to seeing the smoothing effects of their lens based image stabilization, which runs independently from the shutter action.
Things are changing though; Sigma and Tamron have recently come out with their own versions of lens based IS systems available in the Sony alpha mount, Sigma calls their system OS for “Optical stabilizer” and Tamron uses VC, or “vibration compensation.”
I’ve long had questions about how these lens based image stabilization devices would work with Sony, such as; does it offer additional compensation from movement as opposed to the Sony system, and most importantly, what happens when you use both systems simultaneously!! Fortunately, I have a copy of the Sigma 70-200mm F/2.8 HSM OS lens to help answer those questions.
Go to the Sony SteadyShot VS Sigma optical stabilizer page for a full report. This is a general summary of my narrow use of the Sigma OS system only, and not meant to be broad and scientific in nature.
To sum this up; YMMV, meaning my results here may not be the same as what you’ll get using the same exact testing procedure. You may be more steady, or more shaky than I am. Please read the whole intro before looking at the crops.