DSLR Camera Wear in Video Mode

[bmpress]

Hi Bob,

I was looking for information about camera life when just shooting video on a DSLR. I gather that the camera uses a "rolling shutter," but don't know how this works. Any information would be appreciated.

Barry

[KeithB]

I am not Bob, but...

Rolling shutter simply means that the chip is scanned line by line, so it takes a finite amount of time to get the whole image. The alternative would be to take the image, "freeze" it somehow and then read it out. Since a mechanical shutter cannot work at 30 frames per second, it is not possible to "freeze" the image since the sensor is exposed to light all the time.

So, there is no *mechanical* wear when taking video, since no mechanical movement, i.e., shutter or mirror, takes place while shooting video.

Also, since no mechanical movement involved, it does not wear out the electronics to take millions of images vs thousands.

However, taking video does cause the sensor to run warmer than it would taking still images. Chips do wear out faster when warmer, but I doubt that this affects the lifetime of the camera. Canon does have a temperature sensor that stops video if the sensor gets too hot, so the Canon engineers are sensitive to this already. (This could be strictly for noise reasons, since warmer chips are noisier, too.)

[Bob Atkins]

Keith is absolutely right.

CMOS sensor cameras typically use a "rolling shutter", which is essentially reading out the data a line at a time in real time as the exposure is made. This can distort moving objects but has benefits such as increased sensitivity over a "global shutter" which first exposes the whole frame, then reads it out.

While a global electronic shutter for a CMOS sensor is possible, it's just not used much. I'm not sure why but it probably has to do with CMOS chip design complexity and cost. However with CCD based cameras, a global electronic shutter is often used because the electronics of CCD sensors are such that a global shutter is easier than with CMOS.

Video on a DSLR wears nothing out. There's no mechanical involvement with CMOS rolling shutter. Ket's right about increased temperature, but that's very unlikely to cause a problem. If the temperature gets too high, the camera shuts down.