Though this wasn’t the sole reason for me to purchase the Sigma 17-50 F2.8 EX DC OS HSM a week ago I had to give the OS a try.
One of the results is the image below, where I could disobey the rule of thumb of the minimum shutter speed. In this case I wouldn’t have chosen a shutter speed lower than 1/50 of a second. The reason for this is obvious as the rule of thumb says: if you shoot handheld the maximum focal length of your lens should be the minimum shutter speed that you choose.
In this case this would have meant that I would not have been able to get this smooth water effect.
Have a look at the image, then read the specifications below and be surprised.
The only thing I did to stabilize myself was leaning on a rock and than shoot the image handheld. My focal length was 50mm at f20 and the shutter speed was 1/3 (!) of a second. Due to the weather circumstances the ISO was set to 400.
The low shutter speed gave me a nice smooth waterfall. Exactly as I wanted it. Despite the low shutter speed on the other hand the image is still quite sharp. Now I look at it the question comes up in my mind why I cut off the rock on top of the image (should have zoomed out a little more).
My conclusion so far on this lens is that I love it and for the price of $830,- here in the Netherlands it still is quite affordable. Of course customers in the US have a big advantage here as the price over there lays somewhere between the $600,- and $700,-. Did I told you that I envy you?