How to double FPS in output file

mlody · Nov 2, 2017

Hello.

I'm running some test, and trying to achieve to have doubled FPS in Mavic output video file.

I've set the FPS in Mavic settings for 25fps (4K, PAL), I chose manual camera settings, I've set the Shutter Speed for 1/60s, and... nothing is changed. My output video file is still 25fps, not 50fps (that's what Windows explorer says).

Why is that?

PS About environment. I run this test late in the evening, inside, with quite low level of ligh. But i don't care because only thing I want to achieve now is doubled FPS. So i asume that light level isn't important for that kind of test.

Mr. Salty · Nov 2, 2017

I'm not sure I understand. The Mavic can't shoot 50fps at 4K. Why do you think your frame rate would double?

Qoncussion · Nov 2, 2017

mlody said:
I've set the FPS in Mavic settings for 25fps (4K, PAL), I chose manual camera settings, I've set the Shutter Speed for 1/60s, and...

Then you will get 25fps, with each frame exposed for 1/60th of a second. Shutter speed has nothing to do with changing frames per second. Nothing will change fps, except for changing fps.

mlody · Nov 2, 2017

Watch this. In 39 second of tutorial that is explained...

Qoncussion · Nov 2, 2017

I do indeed understand how it works. My answer above still stands. All he's talking about in the video is setting your shutter speed to 2X the FPS. This does not give you twice the FPS, it simply exposes each frame for approximately half of the time it is on screen.

mlody · Nov 2, 2017

Ok. So tell me now... How to be sure is those settings works? Is a good way to (for example) check file info in Windows and see how many FPS it shows? Every tutorial about ND filters says about doubling FPS.

mlody · Nov 2, 2017

I'm barely sure that earlier on those settings, system info on my recorded videos was showing obout 47-50 FPS. Now it's only 25.

Qoncussion · Nov 2, 2017

Yep - in Windows, right-click > Properties > Details (tab)

mlody · Nov 2, 2017

Ok but in that case, should it be 25 or 50 FPS?

Qoncussion · Nov 2, 2017

If it is set to 25fps - it will ALWAYS be 25fps (period).

Roamer105 · Nov 2, 2017

You are loosing me (maybe others) in this discussion. I really don’t understand this obsession about twice the frame rate shutter speed. All you get is a lot of motion blur. I have taken a load of videos with the Mavic with ND filters and without. I have not seen ANY jello regardless of the shutter speed and I tried anything from about twice to 100+ times the frame rate. No jello. However you get really nice crispy video with a reasonable shutter speed about 10 times frame rate using an ND8 or ND8CPL used in this video:

TheoMatthias · Nov 2, 2017

To the OP:

I believe you are confusing frames per second (“frame rate”, a.k.a. “frame angle”) with shutter speed. At 25 FPS, the recommendation for a natural motion blur is to set the shutter speed at two times the FPS, or 1/50 of a second.

I highly recommend viewing this video to see how frame rate (FPS) and shutter speed relate to motion blur:

Remember, when we look at moving images in real time, the eye and brain introduce a degree of motion blur. Shooting at 2x your frame rate comes close to mimicking the motion blur that the human body produces.

Also, if you haven’t already done so, you should completely understand the exposure triangle. However, remember that with the Mavic’s Camera, your aperature is fixed at f2.2.

Finally, don’t forget to minimize video “noise” by keeping your ISO setting around 100.

dwallersv · Nov 2, 2017

The 2x shutter speed vs framerate is simply a videography rule of thumb to avoid the sharp, videotape-like appearance, instead creating a more film-like appearance by allowing some motion-blur.

This looks more "natural" because human perception is also affected by some motion blur (for reasons I forget at the moment, but the same that make fast-changing displayed frames look continuous -- a movie).

There are circumstances where you want to explicitly "freeze" each frame, in which case you abandon this rule and use as high a framerate as possible. For example, scientific high-speed photography.