When looking at my pics from the last TLP, 1/3 were unsharp, although at shuuterspeeds between 1/800 and 1/1000.
As a test, today, I went to Volkel to take pictures with my 100-400mm lens but this time without the Tiffen Haze-1 filter.
I was impressed with the difference.
An italian viper at 400mm ISO125 T1/800 A8.0 --slightly blurred, but not due movement--

Dutch viper at 400 mm ISO160 T1/800 A8.0 --sharp!--

All pics are straight from the CFcard, some cropping but no sharpening and such! Also IS was on in mode2.
For the time being I will refrain from using my filter, but I have ordered a B&W 010M filter, which was recommanded at another forum.
greetings