film making – photography – education – astronomy
I want to talk about video recording with digital cameras. I own a Canon EOS 200D, is an entry level DSLR camera, it doesn’t have a really high quality sensor, but I feel I can make really high quality films just making sure I have the right settings before pushing the record button. The quality of any camera is always dependent from the lenses so it can be increased simply by purchasing better lenses, so do not underestimate cheap cameras, it’s a good purchase for anyone just looking at this hobby for the first time and is always more fun to push the limit of what you can achieve with what you have.
The default settings of a consumer camera, DSLR or mirrorless, don’t leave you much to do before recording, all the settings might be in auto mode, so in order to follow my article, you really need to change the video mode to manual, so to have more control over the settings.
You might have more or less choices depending on your camera, but even an entry level camera should have 24, 25, 50 and 60 frames per seconds options available. This value indicate the number of frames recorded in one second. I say immediately that the most used frame rate is 24 fps, the majority of films are recorded at 24 fps, 60 fps are good for gaming but you should leave them for games only.
Does it matter if I record at 25 frames per seconds? Not really, do as you like, the 24 or 25 fps is not anymore an issue, many TV nowadays support both frame rates so you should not worry about it, but I would still go with 24 since the majority of films made are recorded in 24 fps.
So I recorded my video in 24fps, but I like slow motion, in post processing I slow down the speed at 50% and now my video is terrible. That’s because it is missing frames, slowing down the speed means that you are actually extending the duration of your videos but without enough frames to cover the new duration, is not going to looks that good.
Recording at 60fps help slowing down your video in post processing, you can also record in 120 fps or event 240 fps, if your camera support it. With your footage recorded at 60 fps, you open your editing application, and you want to create a slow motion sequence, what you can do in order to keep the standard 24 frames per second? To start you should create a sequence at 24 fps, than you move your video into this sequence and you slow down this video at 40% and than you have your beautiful slow motion. I said 40% and not 50% or 20% because you are creating a video in 24 fps so in order to adapt a 60 frames per second video you need to multiply it by 40/100, what we did here is reaching the smallest speed necessary to have a fluid video without any missing frames. If you record the video at 120 fps than you can go further and reduce the speed at 20% since 120 fps * 20/100 would result in 24 fps.
Best practice says that you should record in 24 frames per second for normal speed footage and more high frame rate if you want slow motion. Also you should not mix 24 or 30 frame rate together since you will not get a fluid video, the 30 frame rate video should be set at 80% of the speed in order to use it into a 24 frame per seconds sequence.
What I can do if I have footage from different cameras and some of them just shot at 30 frame per seconds? I resolve this issue recording at 30 fps or double the frame if I can on all the cameras. Of course I will be able to do slow motion only for those video recorded at 60 fps or higher, also I can just move this footage at 60 fps in the sequence without slowing them down and I will still get a fluid sequence at normal speed with no missing frames.
Talking about frame rates get a bit confusing, so I will try to summarize with some keywords.
Records at 24 or 30 frames per seconds for normal speed videos.
Records at 60 frames per seconds if you want to slow down your video, but remember to create a sequence at 24 fps or 30 fps first!
Depending on where you live, you might have different frame rates, ex. 25 instead of 24, 50 instead of 60, etc. but the same formula apply, just don’t mix them.
Use this formula to find the minimum speed to slow down your footage:
Lowest speed (%) = main sequence frame rate * 100 / footage frame rate
The shutter speed should be double the frame rate, If you shoot at 24 frames per seconds than you should set the shutter speed at 1/48 ms, if you shoot at 30 fps than 1/60 ms, if shooting at 60 fps than 1/120 ms and so on.
Slow down the shutter speed for a more dream like scene, the scene will look more blurred.
Rise up the shutter speed for action scene where you have fast moving subjects.
You can keep it in auto, I understand that many people don’t want to be bothered my tons of settings to change so you can just leave this setting in auto and just leave this task to the camera. If you decide to keep it in auto you should limit the maximum ISO the camera can pick, I usually don’t go over 1600, If the ISO is set too high, you will lose quality since the signal to noise ratio will rise.
I talked about the three main settings, frame rate, shutter speed and ISO and all three are fixed, so what we do if the image is too bright, overexposed, what we can change? We should not change anything, the only thing we can do is limiting the light passing through the lens with a filter. A neutral density filter, has the job of reflecting part of the light, you can find fixed and variable ND filters, but I prefer the variable since you don’t need to switch them depending on how much light there is outside, you can rotate the ring and the filter change in power. The quality of these filters can vary greatly so always check the price, and choose filters in glass or other strong materials.