Water Droplets - Freezing motion

Playing in the sprinkler last night with my daughter I attempted a fast shutter speed technique to freeze the motion of the water coming from the sprinkler.

With my telephoto lens attached to my Nikon D3100, I took the following.

Focal Length: 195mm; Shutter Speed: 1/4000; F-Stop: f/5.3

Focal Length: 122mm; Shutter Speed: 1/4000; F-Stop: f/4.8 

Focal Length: 75mm; Shutter Speed: 1/4000; F-stop: f/4.5

In order to shoot these photos, I used "Shutter Priority" mode on my camera.  Focusing on the water droplets instead of the car or trees in the background was challenging.  In autofocus I had to first focus on my husband holding the sprinkler and then focus on the water that was at the same distance from me.  Or I had to use manual focus.  Using manual focus was challenging because the water was moving so fast and was so small I couldn't see it very well to tell if it was in focus.

I'm please with these photos, but of course want to do better.

Thoughts for next time

• shoot with the sprinkler on the ground (someone holding it was too chaotic)
• get some sun spots by shooting at sunset and have some backlighting or frontlighting effects
• I'd like to try for a faster shutter speed to stop motion even more.
• Go for a slower shutter speed and make it look like flowing water, not frozen movement