17-85 vs 15-85

The 15-85 is a wonderful lens but can be soft at low spreeds. I had massive problems with it at anything from 180/s to about 30/s until someone on here mentioned that the IS can be funny and once you have touched first release, hold for a second before clicking the picture. Found this cured the problem and no longer get the soft images but razor shape ones.

Still takes a while to learn to hold off squeezing the picture once focussed for a second though. But it works and soft images are a thing of the past.