Shooting video using the 50 1.2 L is an interesting experience, to say the least…
One of the biggest things cinematographers and videographers, such as Buster over at A3, have conveyed to me, is the desire to shoot at the lowest ISO possible when shooting video, preferably below ISO 1000, though I have gotten great results at ISO 1600, and I’ll go beyond that, if I know the video is going to be laden with effects in post.
That being said, the obvious requirement to shoot at a low ISO is, lots of light. And “lots of light” in the video world, means something a bit different than in the world of still photography, for a few reasons.
First off, due to the nature of video, you are limited to a shutter speed, at the low end, of 1/30 second. Though, for the best results, most videographers, including Vincent Laforet, recommend a shutter speed of 1/50 second, to mesh better with common monitor refresh rates. So, almost by default, you are limited in your light gathering ability, when shooting video.
At that point, your options are, crank the ISO, open up as fast as your lens can go, or dump a lot of light on the scene. Or any combination thereof.
As an experiment, I chose to shoot the sequence above at ISO 320, 1/50 second shutter speed, all wide open at f1.2. As you can see, Caroline drifts in and out of the zone of critical focus on numerous occasions. However, the video quality is amazing. At ISO 320, the 5D MK II generates superb results. In reality I could have stopped down a bit, since the lighting tech at Blue Martini was kind enough to have the system running at maximum intensity at the time.
I can definitely recommend the 50 1.2 L for video work. It’s a very versatile prime, and the image quality is amazing.