Disclaimer: This post talks only the Video side of the Camera
With the 5D Mark III you have full manual control over exposure and the type of video compression (ALL-I and IPB are supported). For those who don’t know what ALL-I and IPB means, here’s a short explanation:
- IPB – B stand for Bi-directional compression. This type of compression works by predicting the content of future frames. Offers better compression compared to ALL-I.
- ALL-I – or ‘Intra-coded Frame’ is different from IPB because all frames are treated as key frames. No further compression is applies, just a frame compression. This results in better image quality, but up to 3 times the file size. Editing individual frames doesn’t hurt image quality. Furthermore, playing ALL-I compresses files take less computing resources in playback. ALL-i is also referred to as “Editing friendly” format.
So ALL-I only compress the information for the current frame, but not the information between those frames. IPB compression use interpolation and therefore requires more computing processing power, as well provides lower image quality because it deals with part of the image that is the same, and the data that is changed from frame to frame. Because repeated data can be stored only once, the intraframe IPB offers much superior compression but at the cost of image quality and video editing capabilities.
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The Canon EOS 5D Mark III can capture videos in various frame rates and resolutions (including size/min per compression method):
- 1080p (1920×1080) @30/25/34 fpsIPB: 235MB / minuteALL-I: 685MB / minute
- 720p (1280×720) @60/50 fpsIPB: 205MB / minuteALL-I: 610MB / minute
- 480p (640×480) @ 30/25 fpsIPB: 78MB / minute
Rolling shutter distortion (sometimes called “jello” distortion) is a long standing enemy of DSLR video. DSLR sensors do not typically read out the entire frame in one instant. Instead, they read downwards from the top to the bottom of the sensor. This means that the top of the frame is recorded slightly before the bottom and, if the camera pans quickly during this time, the image is skewed like a wobbling jelly.
Improving the colour sub-sampling from 4:2:0 to 4:2:2 would be welcomed by many, especially those that typically do a lot of heavy grading (colour work).
Increasing the colour depth from 8 bit (256 possible values) to 10 bit (1024 possible values) could also give a nice improvement in video quality in many situation.
Color Sub-sampling in Canon 5D Mk III:- The 5D Mark II can output a video signal via its HDMI port and, if you want to, you can record this video stream to an external recorder such as a Nanoflash or Atomos Ninja. These devices are capable of recording at a very high quality, much higher than the Canon 5D Mark II’s internal recording. Unfortunately, the feed that the Mark 3 provides is 4:2:0 compressed video. The new Nikon D4 and D800 can now both output clean (i.e. uncompressed 4:2:2) HD feeds via HDMI meaning that they can be readily used with these external recorders.
Canon 5D Mk III Indian Price: Rs.1,74,950 approx.
