letting out some steam

Lincoln_Rhyme · April 2, 2016

the other day I came to this forum to ask for camera advice and one question I ended up asking was how does a camera record slow motion

On ‎2016‎-‎03‎-‎31 at 6:29 PM, Lincoln_Rhyme said:

how does the camera record slow motion or is this something that can only be done when the video is edited?

These are the answers I got from 2 different people

On ‎2016‎-‎03‎-‎31 at 6:30 PM, .spider. said:

Cameras are recording frame rates.

recording fps/playback fps = speed

On ‎2016‎-‎03‎-‎31 at 6:42 PM, ALwin said:

OK let me first answer this question, then I will go into a bit detail about how I would be filming if your aunt and uncle (hypothetically hired me) to film for them.

Most films and videos you see in theaters, DVD/BluRay, on TV are often filmed and played back at the nominal frame rates of 24, 25 or 30. Let's call these the normal speeds. If you want to record slowmotion, you can take video recorded at these normal speeds and slow it down in post, but then the software you use to edit has to generate the missing frames or your playback speed becomes jittery like 12fps or something (if you convert a 24fps video to 50% slow motion).

Cameras that can record up to 50/60fps keep the videos recorded at those frame rates and you can play them back at 50/60fps. So for video recorded with said frame rates you need to slow it down in post, say 60fps played back at half speed of 30fps makes the motion in the video half as fast.

But for cameras that can record over 60fps, for example 1080p 100/120/150/200, etc. frames per second, the camera doesn't keep the video files on the memory card at those high frame rates. They are already converting the video to the normal speeds for you. (OK I need to be a bit more precise on this). If you want to record at such high frame rates, you have to differentiate between video frame rate set for what the camera saves to the memory card and the actual frame rate that the camera is recording. In most cameras you cannot choose anything besides the following (for 1080p, very few sub-$3000 cameras do 4K high frame rates):

1080p24, 25, 30, 50 & 60 (including ones like 23.97, 29.97, etc.) Cameras usually do not have a setting like 1080p120. This is for choosing the recording resolution and playback frame rate.

Then in the camera, if you enable S&Q mode (in Sony cameras) you can select a recording frame rate that is separate from the frame rate that you selected above.

For example, if I select in my camera 1080p24 and enable S&Q motion to record 120fps, when I take the memory card and play the video file on my computer, the camera has already remapped that 120fps to 24fps play back speed. No need for me to do anything in post.

I am not familiar with how other cameras might do this, but I think the steps will be similar for high frame rate recording.

only one person answered in detail how a camera records slow motion. the other person did not. so when I told him his answer did not explain anything he starts acting like a jerk or a spoiled brat. and later when the person who answered in detail and explained things to me said I could pm him or some other members if I had more questions that jerk starts insulting their intelligence.

that jerk's exact reply when I said he didn't explain anything