Timescapes - Digital Timelapse Discussion

No slow motion at high frame rate?
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Author:  tribal-warrior [ Sat Aug 13, 2016 9:00 am ]
Post subject:  No slow motion at high frame rate?

As many will know, the PAL version of the Panasonic G6 has an option to record at 50fps. I wanted to use this setting to shoot some slow motion footage. My only previous experience with filming at high frame rates is with movie film (super 8 in particular.) I had a Canon 1014 Autozoom Electronic super 8 camera which had a top speed of 54fps. The principle for producing slow motion footage with this dinosaur technology was pretty simple – film at 54fps and then project the developed film at 18 or 24fps. The results were great by the way – beautifully smooth slow motion.

Now back to this Panasonic G6 footage – when I placed the footage on the timeline in Sony Movie Studio, I set the video properties to 1920 x 1080, 50i (25fps.) And also exported the clip at 50i (25fps.) The result? Motion looks completely normal. There is no slow motion. I'm seriously puzzled.

Author:  edward [ Sat Aug 13, 2016 2:02 pm ]
Post subject:  Re: No slow motion at high frame rate?

I don't know about your setup or camera, but with a GH4 shooting at 50 fps, I import it into After Effects and then I go to Interpret footage and set it to 25fps. Then the movie runs at half the speed. I save as 25fps.

I think your problem is that you are recording at 50i, and not at 50p. 50i means it's interlaced, two fields, so you are actually recording at 25fps. See if you can record at 50p (progressive) and you should be OK.


Author:  geraldft [ Sat Aug 13, 2016 3:42 pm ]
Post subject:  Re: No slow motion at high frame rate?

Fairly certain you can slow down 50i footage, but due to interlacing it may not look as nice.

On a PC, depending on settings, you normally see both fields as one - they are blurred together.

In fact 25i is two fields at 25fps so actually 50 fields per second. 50i is 100 fields per second. Each field is half the full resolution.

In Vegas you can slow down two ways. Insert a "velocity envelope" which can be keyframed, or right click the clip and select properties, then set playback rate to 0.5.

If it is 50i you can also try 0.25 at the cost of losing half the vertical resolution...

Author:  tribal-warrior [ Sat Aug 13, 2016 7:06 pm ]
Post subject:  Re: No slow motion at high frame rate?

Nope. The footage was recorded at 50p, not 50i. Here are the exact specifications from the camera's menu:

AVCHD Progressive, 1920 x 1080, 50p, Image Sensor Output 50p, 28Mbps.

Though oddly, when I first import the footage into Sony Movie Studio, the software indicates that it's 25fps footage. But that can't be. I'm 100% definite that I was recording in 50p. And I selected a shutter speed of 1/100 for pleasing looking footage.

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