Shutter Speeds

[Taylor Lamb]

If I'm shooting on my Red at 23.98fps at a 1/72 shutter speed. What shutter speed do I need to make my 300fps footage so it matches with the 23.98fps footage?

 

[James McLellan]

Typically people shoot 180 shutter which would mean 1/48 for a frame rate of 24 frames per second and 1/600 for a frame rate of 300 fps. I think after 72fps most people are shooting 360 shutter so as close to 1/300 as you can get and thus I think 1/320 may be it. Would have to boot up the camera to see for sure. 1/48 shutter at 300fps defies the laws of physics. Is there a reason you are shooting 23.98 at 1/72? 1/72 is what the Hobbit was shot at I think.

 

[Taylor Lamb]

23.98 at 1/72 is just the look I want to go for. I'm taking the 23.98 footage and rotoscoping it over 300fps footage, but I want it all to match. So I'm trying to figure out what shutter my 300fps footage needs to be to match the 23.98 footage.

 

[James McLellan]

When you say match I assume you mean match the shutter blur. You can't shoot 1/72 so you would want to shoot as close to 1/300 which is as slow a shutter as you can shoot. Am I missing something? It doesn't appear as though you have a lot of options.

 

[Paul Watt]

If you handle the shutter angle in degrees the camera will automatically make the changes for you. 1/72 at 23.98 is about 120 degree shutter. That's gonna be around 1/900 for 300 fps, but easier to just set 120 degrees

 

[James McLellan]

That makes sense mathematically. Does it make sense visually? Since the relationship with shutter blur and shutter angle is not linear does it still work? I was not aware that one should match slo mo shutter angle to the timebase shutter angle. Is this a common practice? You learn something new every day on reduser.

Edit - Wait a second. Shutter speed and blur do have a linear relationship. So is this common practice then?

 

[ericyoung]

If you're trying to match the blur characteristics, you need to keep the shutter speed (in fractions of a second, rather than shutter angle) the same, or as close to the same as possible taking your framespeed into account - ie what James said in posts #2 and #4 above. Of course 1/300th of a second's blur isn't really near to 1/72 secs, so it won't be the same. Some motion compensated blur filter in post will probably be needed for that.