Question about fps clips vs fps of timeline

[Andy Into The Wild]

Hi there,

In a couple of weeks I'm taking a big trip which I want to make a 'home movie vlog' type video for personal consumption....I've done this before but used full auto for everything, and this time I want to do it 'properly'.

I understand frame rates and shutter speeds, but what I'm not clear on is whether I can shoot everything at 50fps on the basis that I don't know what I'm going to want to slow down later. I intend the timeline to play back at 25fps, so my specific questions are:
- can I shoot at 50fps for everything and just play the clips back at 25fps at 'normal' speed without issues?
- if yes, do I need to shoot at a shutter speed of 1/100 per the normal rules? Or can I get away with 1/50 at 50fps?

Also for context, "without issues" means smooth looking, non jerky video, as I don't particularly like the look of 50/60fps video playing back at that frame rate.

I guess the alternative is to decide before shooting what I want in slo-mo and shoot that stuff at 50fps, with everything else at 25fps.

Thanks

 

[ah5168]

If you use editing software like Premier Pro and you can shoot at 50 fps and either convert the time base to 25 fps, so a 10 second clip at starting at 50 fps with still be a 10 second clip when converted to 25 fps and the audio will be OK. Or you can slow it down by 50% which will stretch a 10 second clip to 20 seconds. This will give you 2x slomo but the the audio will also be stretched and slowed.

Also you need to consider how much storage you are going to use, depending on the compression method you use you may need a lot more storage to shoot at 50 fps.

If you're not worried about storage and don't need the audio then shoot everything at 50 fps. If you do need audio and storage is an issue shoot in 25 fps unless you want slowmo then go to 50 fps but just for those clips.

Other things to think about.

Lots of the world has 60 Hz mains power, if you are shooting in artificial lighting in these areas then you may get some strobing by shooting at 50 fps and you may need to shoot at 30 or 60.

If you want to play back the finished footage on a computer monitor, they work at 60 fps so you final edited output needs to be at 60 or 30 fps for smoothest playback, if play back is a TV you need 25 or 50 fps. Phones or tablets are able to handle a variety of frame rates and still playback smoothly.

If you can keep the shutter speed at 1/50 second you will get much smoother motion you may need to use ND filters to do that but it's worth it if you have a lot of motion.

Check out this panning speed calculator on the Red website you will have to select the red camera that has a sensor size nearest to your camera and you can then calculate the best panning speed for your frame rate lens etc. If you move the camera too fast for your frame rate it will start to look choppy, faster frame rates allow faster movements.

It's best to think about how you want to present the finished footage and work back from there.