Damp days can make for great prop vortices on takeoff.  However, I have been feeling less than satisfied with my results recently.  As I was going through some shots, I made a discovery that should probably have been something I worked out before.  I like to have a good amount of prop blur so drop the shutter speed down when I can.  I go with a high frame rate with the aim of getting a good sharp shot amongst the more blurry examples.

As I go through the shots, the sharp ones have okay prop vortices but not great.  Then I will come across some really nice vortices but the shot is otherwise not sharp.  It seems that, in panning with the plane to get a sharp shot, the trailing vortex gets blurred out.  If I am not panning well, the vortex can be the thing I have tracked better and it shows up well.  I have seen shots from others with the props almost frozen with a high shutter speed and the vortices easily seen.

Consequently, I am going to have to make a decision in future.  How much prop blur do I want versus the ability to see the vortices well.  A little trial and error will be involved.  At least it is fall/winter so the Pacific Northwest will probably provide me plenty of damp days on which to experiment!