Immaculens wrote in post #17519047
picked up the Sigma 150-600mm (C) OS today. A few first impressions are positive - I like the quick accurate AF, and I 'really' like how there is a lock on all major focal lengths. The weight is reasonable, as is the build. I am not impressed with the OS (Optical Stabilization). My EF 70-300mm L IS is more stable at 300mm than the Sigma at 150mm..
I noticed the same comparison Will. The 70-300L IS just locks in and keeps things very stable, whereas the Sigma OS is a bit hard to detect, and lens/camera movement is more noticeable. I like that things are not jittery like other lenses I have seen, but I this may be the one area where I expected better. I like the OS is very quiet, and I will say it has not kept me from getting a shot and not anything that makes me want to return it, but it's one of those observational things. I am wondering to what degree any adjustments through the dock could change/enhance the OS.