Let's Talk Video Frame Rates
/
Hi folks. This time around I want to spend a bit of time on video frame rates. This is one of the issues often raised when still photographers are asked why they don’t use the typically amazing video in their cameras.
I get that the majority of stills photographers never do video. It’s a different medium and a different skill set, yet at the same time, these fine people will shoot videos on their smartphones. Why is that?
Perceived simplicity. The mobile devices make video really easy masking any of the complexity.
So why use your larger sensor camera? Really its about control. Smartphone sensors are small and have seemingly infinite depth of field which is great unless you want to control depth of field. The same can be said for gain control. However, in this article we are going to focus on frame rate.
What Is It?
Many still photographers, maybe even you, get excited learning how many frames per second a camera can shoot in burst mode. While this can lead to dozens, perhaps hundreds of unused images, folks love the sound of that “motor drive”. Yet while video frame rates are basically faster versions of the same thing, there is no chatter from the camera and perhaps this makes it less exciting.
Video frame rates are measured in frames per second. Back when broadcast was king, we had two standards, NTSC and PAL. While most cameras still support both options, these things have become less important when streaming is the way the majority of video is delivered, consequently we will spend our time on the very common NTSC frame rates, however, the rules also apply to PAL.
Frame Rate Examples
The 24 frames per second frame rate (I will touch on the 23.98 fps rate in a separate section) comes from cinema film cameras. Basically it meant that the motors moved the film through the exposure gate so in one second, 24 distinct frames would be recorded. For all intents and purposes, this meant a (converted for stills folks) a shutter speed for each frame of 1/48 of a second. We know that this is a relatively long shutter speed. It is still handholdable and since we only see one frame for 1/24 of a second, some of the possible blur created by a subject in motion will never be detected by the human brain at a single frame level. However, a sequence of frames of a subject in motion will create a clip that has a bit of motion blur, depending on how fast the subject is moving. This motion blur is what folks like to refer to as “film look” and while that is sometimes misinterpreted to mean it looks like a particular film stock, it means that there is some level of motion blur that the eye and brain have become accustomed to.
The 30 frames per second frame rate was the default frame rate at the dawn of video. It is delivered by an effective shutter speed of 1/60th of a second, and each frame of video is visible for 1/30th of a second. This shortened duration of visibility, and increase in frame count per second creates the mental image of less motion blur and thus “sharper” images. This is often referred to as the “video look”. It’s very common and for most things is more than acceptable.
The 60 frames per second frame rate was first devised to deliver “sharper” clips, meaning a shorter shutter speed to use with subjects in higher speed motion. This means that in one second, you will see 60 frames, and the effective shutter speed for each frame is 1/120th of a second, or round up to the more common 1/125th of a second in most cases. This freezes subject movement better if you have fast action. Think an athlete at peak movement, or a race car as examples.
We now are seeing higher frame rates become more widely offered, with point and shoot cameras offering frame rates on smaller sensors as high as 960 frames per second. While this might lead is to think that we need these frame rates for really fast subjects, like a hummingbird’s wings, there is a more widely used rationale and that is to create slow motion clips. For example, if I shoot a subject at 120 frames per second, I could then slow that clip down to playback at 30 frames per second. This is the same as playing back at 1/4 speed. The images are still nice and sharp but the ability to delineate movement elements is improved. This capability is widely used in sports to diagnose golf swings, or pitcher ball releases, but is also used to bring even more excitement when interspersed with “normal” speed for things. This is widely used in MX cycling and skateboarding clips to add drama and a different “look and feel” . If you shoot something at 960 frames per second, and play it back at 30 frames per second you get slow motion at 1/32 of normal playback, and here’s where your hummingbird wing clip may be very interesting, or very boring, depending on the viewer.
Playback and Editing Video
It used to be that playing video back on some computers required extra software. Not today. Macintosh computers come with Quicktime Player which is superb, lightweight in terms of resource usage and it even offers some basic trimming tools. Those on Windows will have Windows Media Player which also works very well and costs nothing extra. Certainly there are other players out there, and they are useful if you have odd recording file types, but most all cameras give you a choice of .MOV or .MP4 for recording file format and these are nearly universally accepted. I will leave the unnecessary bun fight over which one is better to the Internet. Both work just fine for most everyone.
It used to be true that if you wanted to edit video, you needed to spend a lot of money and learn very complex software. Back in the olden days, it took me a while and lots of determination to learn to be a decent video editor. Here in 2021 when this is written, Macintosh computers come with iMovie which for non-editor types has got to be the simplest and quickest video editor around. Serious editors will poo poo it because it masks all the techno babble. If you run Windows, the old simply named Movie Maker has been replaced by Video Editor which is part of the Photos app on Windows 10. With Windows 11 just having shipped when this post goes live, there is an updated more powerful version therein. If you want serious video edit capability with a super simple user interface consider Adobe Premiere Elements. You can even get a free version of the professional’s choice DaVinci Resolve, just understand that it is designed for video pros and will have a longer learning curve. I use Resolve pretty much exclusively, but my use cases are likely different from yours.
What About Those . Frame Rates? And the Letter Ones
You will sometimes see frame rate options including 23.98, 29.98 and 54.94. These exist specifically to support the clocking in NTSC broadcast. You can use them for streaming but it’s not necessary. If you only see these options, choose the one closest to the general frame rate that you want. All will be fine.
You will also see frame rates followed by an i or a p. Simply put, I means Interlaced, which is a combination of two fields, odd and even. p means progressive, meaning a single frame. Older devices may only be able to play back interlaced, but most modern devices including streaming can handle p. Pretty much anything that can handle progressive can also handle interlaced, but not necessarily the other way around.
Give it a Try
If you find video easy on your smartphone, it’s similarly easy on your stills camera. For your first few clips, try putting the camera in fully automatic mode, turn on the video function and just shoot some clips. As you figure out how easy it is, then you can start to get into the deeper settings such as frame rate.
Do you have an idea for an article, tutorial, video or podcast? Do you have an imaging question unrelated to this article? Send me an email directly at ross@thephotovideoguy.ca or post in the comments. When you email your questions on any imaging topic, I will try to respond within a day.
If you shop with B&H Photo Video, please consider doing so through the link on thephotovideoguy.ca as this helps support my efforts and has no negative impact whatsoever on your shopping experience.
If you find the podcast, videos or articles of value, consider clicking the Donation tab in the sidebar of the website and buy me a coffee. Your donation goes to help me keep things going.
Click this link to submit your questions
I'm Ross Chevalier, thanks for reading, watching and listening and until next time, peace.
