I was doing a test for some slomo green screen and I decided to shoot at 1/120th of a second to help with sharper edges. Then I thought about my normal (default) shutter speed of 1/60th and thought how that sometimes adds to an overall softness of objects in motion. Why not make 1/100th my new default? Any thoughts on the subject? Other than needing a bit more light, I don't see a downside. Thanks.
In 60 Hz countries shutter speeds are increased in multiples of that number so you don't have to worry about rolling picture and flickering in artificial lighting. The fact that you're talking about green screen work sends up a red flag for me: it's all artificial lighting.
You're trying to find a happy medium between shooting within NTSC standards for good quality but also to get closer to your aesthetic vision. Combining the two is never ever a bad thing. All of us want to push the envelope and that's what makes you an artist. Green screen work is all about pulling good keys and that means well defined edges with good contrast and minimal green spill from the lit background. To proceed you need to test, test, test. If it works to your satisfaction nobody's going to tell you what you're doing is wrong. But make damn sure you're right before shooting for real.
I hear you saying that 1/120th second would be better than 1/100th for shots that involve artificial lighting. The test footage I shot was set to 720/30p at 60 fps at 1/120th shutter speed and it looked good on playback. My editor will do a test key Monday to see if this helps in getting cleaner edges on moving arms, etc. Thanks for your input. I'll post those results.
I generally go by double the frame rate as my ideal shutter speed. 24fps = 1/48, 29.97= 1/60. etc. That gets you between too low a shutter speed which is smeary, ghosting video look and too high a shutter speed which is staccato, Saving Private Ryan kind of look. Both have their place but realizing those are the extremes gives you the understanding of why the middle is often the best way to go for 'normal' looking footage. It's just another little tool to have in your tool box.