☙ Another DSLR video shooting tip: Rack focus aid
Recently, I found myself in a rather frustrating situation. I had trouble keeping my subject in focus as she moved from sitting in a chair to sitting on the floor for her demonstrations. I tried to rely on the LCD to focus (remember that in movie mode you must use the LCD to focus). I had to come up with a solution.
For some people I imagine using Focus Peaking or Zoom Box settings alone (Magic Lantern firmware hack) might work. But, for me, I keep over shooting the mark even with these great tools.
So, I think you should still give this technique a try.
A pair of wide rubber bands and a few different colored sharpies is all you need.
Notice how close the rubber bands are to each other. You want to keep them
close but not touching (to prevent binding).
In the picture above, I’ve placed one mark on the rubber band that is on the lens body (this band does not move).
On the focus ring I’ve placed the other rubber band. Here I’ve determined my first focus setting based on her sitting in the chair and placed a corresponding mark on this band (gold mark). I then had her move to the position on the floor and placed another corresponding mark on this band (red mark).
The concept is pretty simple. When she moves to the second position, I can rotate the ring to the corresponding mark and be confident she is in focus.
Now, I will say that I tend to double check Focus Peaking on the LCD just to make sure it is accurate.
Please note that most lens have a focus ring slip feature. The focus ring can rotate beyond the stop mechanism. You must not go beyond the mechanical stop else wise your marks will be off.
I like using rubber bands better than tape because of the residual glue that I would otherwise have to clean off the lens.
Prepare with practice and photograph like a professional.
Victor Osaka, Photographer