Europe lives in 50Hz and US in 60Hz, or, why the 5D 30 fps video is an issue in Europe
Posted by: Sulka
So, if you read the comments to my previous post on the 5D video issues, people are saying supporting just 30 frames per second video capture in Europe is not a problem, since HDTV sets can display a number of frame rates, some of which are some multiplication of 30 fps (such as 60i or 60p - there are no 30p sets). Now, this is true, but this claim ignores the fact that European HDTV penetration is currently at somewhere close to 20%, and just 1% of the HD sets are actually hooked to a HD source (source).
This effectively means that if you want to share any clips shot at 30p, more than 99% of Europeans can only display your footage in a format native to Europe, which happens to be 50i. This in turn means your signal quality will reduce significantly. Oh, and, all European HD channels apparently broadcast using 50i or 50p.
But this isn't the real problem, and I was dumb not to state this in the previous post.
The 30fps support causes issues in thee respects: capturing the footage, editing the footage, and displaying the footage. The displaying is pretty much covered above, so let's continue with the two others below. The part where you especially need to play attention to is the capture part, as that will affect even the users planning to shoot cat videos to display on their own brand spanking HD set.
European electric current is distributed as alternating current (AC), with 50 hertz frequency on the waveform. Simplified, this causes the native operating frequency of any electric device connected to AC to be 50 hertz, unless the device explicitly overrides this by changing the current. Unfortunately, lighting is such a simple form of electronics that vast majority of indoor lighting oscillates at 50 Hz, or a multiplication thereof, such as 100 Hz.
The relevance of this fact comes in when you start to shoot video with artificial lighting. If you shoot at a frame rate which is an even multiplication of the current used for the lighting, you're fine since each frame will get the same amount of light as it'll be in synch with the lightbulb oscillation. However, if you shoot with a camera that uses a frame rate other than the light oscillation rate, each frame will be exposed with a different amount of light. With video cameras, this causes the exposure electronics to start compensating the lighting difference with each frame, causing funky image quality issues.
This is such a problem that apparently TV studios not only synchronize (lock) the frame timings of each camera in the studio to each other, but use the incoming electric current's wave as the synch reference to time the frame exposure perfectly to the light oscillation.
So, in case of 5D with 30 fps which doesn't play nice with European indoor lighting, if you want good quality footage, you can't shoot any video in locations lit by artificial light. No sports videography, no indoor shots.
The Canon pro video department knows this, so it makes me think if they've intentionally sabotaged 5D by not letting the Canon camera department know.
The editing issue is less severe. The problem is also quite simple to understand. If you want to edit a set of footage, there's no magic way to support multiple frame rates in one video clip rendered out as a result of the editing. Hence if you have some footage in 30p and some in 25p or 50i, some of the footage will have to be converted into the frame rate you want to use in the resulting video. This in turn means that if you have any existing footage you want to use with shots created with 5D, the chances are that stuff is in an incompatible frame rate, and something has to be converted, resulting in one of jerky motion, slowed motion, sped up motion, or ghosting. For home users this might be acceptable, but don't expect to be able to ever sell your footage you shot with your 2500 € camera since the people purchasing the footage will use other footage as well, and will not want to convert frame rates. And I assume many 5D users will want to sell their stuff.
Where does this leave us? EOS 5D mark II video will be usable to you if:
That list has more than one show-stopper for me, but your mileage might vary.
For more interesting reading, here's a thread from DPReview, and one in Adobe forums.
This effectively means that if you want to share any clips shot at 30p, more than 99% of Europeans can only display your footage in a format native to Europe, which happens to be 50i. This in turn means your signal quality will reduce significantly. Oh, and, all European HD channels apparently broadcast using 50i or 50p.
But this isn't the real problem, and I was dumb not to state this in the previous post.
The 30fps support causes issues in thee respects: capturing the footage, editing the footage, and displaying the footage. The displaying is pretty much covered above, so let's continue with the two others below. The part where you especially need to play attention to is the capture part, as that will affect even the users planning to shoot cat videos to display on their own brand spanking HD set.
European electric current is distributed as alternating current (AC), with 50 hertz frequency on the waveform. Simplified, this causes the native operating frequency of any electric device connected to AC to be 50 hertz, unless the device explicitly overrides this by changing the current. Unfortunately, lighting is such a simple form of electronics that vast majority of indoor lighting oscillates at 50 Hz, or a multiplication thereof, such as 100 Hz.
The relevance of this fact comes in when you start to shoot video with artificial lighting. If you shoot at a frame rate which is an even multiplication of the current used for the lighting, you're fine since each frame will get the same amount of light as it'll be in synch with the lightbulb oscillation. However, if you shoot with a camera that uses a frame rate other than the light oscillation rate, each frame will be exposed with a different amount of light. With video cameras, this causes the exposure electronics to start compensating the lighting difference with each frame, causing funky image quality issues.
This is such a problem that apparently TV studios not only synchronize (lock) the frame timings of each camera in the studio to each other, but use the incoming electric current's wave as the synch reference to time the frame exposure perfectly to the light oscillation.
So, in case of 5D with 30 fps which doesn't play nice with European indoor lighting, if you want good quality footage, you can't shoot any video in locations lit by artificial light. No sports videography, no indoor shots.
The Canon pro video department knows this, so it makes me think if they've intentionally sabotaged 5D by not letting the Canon camera department know.
The editing issue is less severe. The problem is also quite simple to understand. If you want to edit a set of footage, there's no magic way to support multiple frame rates in one video clip rendered out as a result of the editing. Hence if you have some footage in 30p and some in 25p or 50i, some of the footage will have to be converted into the frame rate you want to use in the resulting video. This in turn means that if you have any existing footage you want to use with shots created with 5D, the chances are that stuff is in an incompatible frame rate, and something has to be converted, resulting in one of jerky motion, slowed motion, sped up motion, or ghosting. For home users this might be acceptable, but don't expect to be able to ever sell your footage you shot with your 2500 € camera since the people purchasing the footage will use other footage as well, and will not want to convert frame rates. And I assume many 5D users will want to sell their stuff.
Where does this leave us? EOS 5D mark II video will be usable to you if:
- It's ok the image quality will degrade if vast majority of Europeans try to view it on their TV
- You plan to only shoot using natural light
- You'll never use anything but 5D footage when editing the video, unless you want to sacrifice image quality
- You never plan to sell your footage
That list has more than one show-stopper for me, but your mileage might vary.
For more interesting reading, here's a thread from DPReview, and one in Adobe forums.