Why has video camera resolution increased so slowly?

[Shalmanese]

Consumer grade digital still cameras have increased in resolution from 0.3MP to 5 - 8MP in a seemingly very short span of time. However, digital video cameras are still stuck at the same 720x576 NTSC resolution. Although some HDTV cameras exist, they are invariably priced outside of the consumer market an even those are barely 2MP. What accounts for this disparity in pricing? What makes it so difficult for video camera makers to increase resolution as fast as still cameras?

 

[russell2002]

The amout of extra data recorded.

A 512MB flash card storing say 400 shots from a 3mp camera,

At 25fps, what portable media could store any reasonable amount of time.

Also I think the rate which data can be read from the CCD has some bearing, but not sure.

 

[Goi]

Probably because it takes an enormous amount of bandwidth and space to be able to display high resolution motion pictures at 24-30fps. Also because there isn't much of a push beyond HDTV resolutions(1080p), which means there isn't much sense in making higher resolution cameras since there aren't displays capable of producing that resolution. Compare this to still images where bandwidth isn't even in the dictionary, and space isn't a problem with GB memory cards being available.

 

[CycloWizard]

Originally posted by: Goi
Probably because it takes an enormous amount of bandwidth and space to be able to display high resolution motion pictures at 24-30fps. Also because there isn't much of a push beyond HDTV resolutions(1080p), which means there isn't much sense in making higher resolution cameras since there aren't displays capable of producing that resolution. Compare this to still images where bandwidth isn't even in the dictionary, and space isn't a problem with GB memory cards being available.

This is exactly it. My lab has a digital camera that can take stills at 22xx by 17xx, but can only do 15 fps at 800x600. The bandwidth really throttles the whole process. There are alternative methods, such as taking the camera's output and capturing it on a computer using Firewire or other hardware (PCI cards), but they're prohibitively expensive and not the ideal solution.

 

[f95toli]

My guess is that noise is another issue. As you decrease the size of each "pixel" the noise becomes gradually worse. Now, if you have still camera you can always get round this by using a low ISO but you can't really do that on a videa camera since low ISO also means that it will take more time to capture each frame.
Of course you can still get acceptable times at say ISO 25 if there is a lot of light but since most "consumer" cameras are made to be used in "normal" light this can't always be done.

One way to get round this is to increase the size of the sensor itself but that would also make the cameras much more expensive.

 

[silverpig]

I'd think it's mainly readout times. A fast DSLR can do what? 3 fps for 9 shots or something? Make that 10 times faster and indefinitely...