As I filmed water, I knew I needed a whole bunch of angles and takes just to give myself enough material to edit down later. One of the shots I tried that didn't make the cut was a slow blur into frame. In animation you can film on the twos (12 frames of movement for 24 frames per second). This can be used to acheive a slow motion effect. Sometimes you can animate on the threes! Well, I thought it would be cool to very very slowly come into focus over a few seconds, but it's easier said than done when each second is whipping by at 24 frames. I'm adjusting the focus ring on my camera by hand, keep in mind.
I tried on the twos and it went by way too fast. It was also a fast stop. Nothing smooth about it. I skipped the threes and (stupidly) tried to move it just once every 5 frames! That produced a transition that would start and stop very abruptly.
The video above is this done correctly. I had used the notches that were already in the focus ring on the camera to judge the distance to move it. But what I needed to do, and what I DID do above, is measure the start and stop distance (one inch exactly). I divided that by 3 seconds of filming, which is 72 frames. Then I divided that in half, because I knew I could get away with filming on the twos. So in one inch I needed 36 marks. I went into Photoshop and made 36 lines that were equi-distant to each other and then scaled it down to 1 inch and printed it! I taped it to my camera and VIOLA!!!
Here's the setup. I used a post-it note because it's an opaque sticker that's easily cut and readily available!