<p>Sigma just had a firmware update for the 150-600 that increases focus speed. I have the C version and can tell the difference after the upgrade. Do it yourself in 10 minutes with the Sigma Dock.</p>
<p>My 70-200 F4L IS and my 400 F5.6L have rotational movement with my T3i, 6D and 70D. My 24-105 F4L has no movement on any of the 3 bodies. My non-L lenses have no movement, even the 50mm 1.8.</p>