I had one occasion when it behaved as if it was frozen,it was a dark bird filling the frame against the light.the lens didnt focus or hunt so i thought it had frozen but all i had to do was point it at something else and it focused,no switching off or anything.
Nice shot.
The exif says this pictures taken at a focal length of 240mm
Is that the real focal length or because you were using the FT1 adapter was it actually 2.7x that because of the crop factor?