Camera Labs

I can't seem to find a direct description or diagram of this by Googling, so if somebody can direct me to material on it, or explain, I'd be most grateful.

When a digital still-image camera uses a video mode, the frame size is much smaller than the largest still image size available. Is the camera then using just a small area of the sensor, or does it use the whole sensor, but a very reduced number of pixels?

The question arises when comparing video from a camcorder, with a very small (comparatively) - sensor, and video from a still-image camera, at about the same frame size. The video from the camcorder seems to be of rather better quality, despite the smaller sensor.

Thanks, Dave.

One immediate giveaway if it were a crop would be a correspoding reduction in the field of view - like a digital zoom. So if you see no reduction when switching from stills to movie mode, then it's certainly using the full sensor width and height - well obviously some of the height is cropped for a 16:9 aspect ratio, but you know what I mean.

I've noticed some cameras slightly reduce the field of view in their movie modes, but not by a great deal, so it implies most of the sensor area is being used.

The question then is whether the movie mode ignores pixels it doesn't need to deliver a lower resolution video frame, or bins them for higher sensitivity. Hopefully it's the latter, but the manufacturers are always cagey about giving out the full details.

As for a camcorder being better quality, what are you describing? Noise, resolution, something else? And are you comparing it to a DSLR with video, or a compact camera movie mode?

I know for a fact that Nikon DSLRs drop every 8th line from the sensor to further decrease the output size, which results in massive stairstepping.

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I take pictures so quickly, my highschool was "Continuous High".