When the panasonic GH3 came out last year, I bought one of the last GH2 available at a good price, and I’m now trying to improve my skills at filming with it.
The GH2 movies are great, but I was too often confronted to the same problem: any moderately fast movement appeared steppy, especially on 24p mode. It took me some time to understand the obvious reason behind this problem…
We’ve been used for decades to watching movies shot at 24fps, that’s what people call the “film look”, and it was achieved by using a 180° rotating shutter in front of the camera aperture, thus a 1/48s shutter speed.
To maintain this film look and avoid a stroboscopic/steppy effect, you have to shoot 24p sequences at 1/50s shutter speed on your DSLR.
A this speed, moving objects will be blurred and blend between frames. If you shoot at higher speeds, moving objects will appear sharply but will result in very unpleasant steppy motions.
So if you have to keep one rule in mind to shoot good videos on your DSLR, I think it should be this one: shoot videos with a shutter speed number that is twice the fps.
On our DSLR, it is then a shutter speed of 1/50s for 24fps, 1/60s for 30fps and 1/125s for 60fps.
And if you want to keep a nice depth of field in every lighting condition, you will have to use a neutral density (ND) filter…