"Fredxx" wrote in message
...
First there are 3 CCDs, where pretty much all of the light is captured and
used. Modern CMOS chips with a Bayer filter immediately by design at are
best 50% efficient. CMOS image sensors have smaller pixels with less
active area that is photo sensitive.

Is 3 CCD (or 3 CMOS) less common nowadays that it used to be on broadcast
and professional cameras? You have the problem of maintaining registration
between the sensors, but as you say, the resolution and sensitivity/noise
will be better because the pixels can be larger for the same pixel spacing
because the pixels are co-located although on different sensors rather that
being side by side with a Bayer filter. Presumably registration corrections
can be made digitally without needing to physically move one sensor relative
to the others, as was necessary with tube cameras :-(

Low pixel count (SD) CCD technology is lower noise than CMOS:

http://www.steves-digicams.com/knowl...ifference.html

CCD noise is SQRT(number of electrons in a bucket) vs CMOS KTC (popcorn or
1/f) noise.

https://en.wikipedia.org/wiki/Shot_noise#Detectors
https://en.wikipedia.org/wiki/Johnso...n_cap acitors

I've been very impressed with the low noise on my Nikon D90 digital *still*
camera. I can see very little difference between pictures taken at 200 ASA
and those taken at 3200 ASA - except on areas of uniform colour. And that's
with a single CMOS sensor with Bayer filter. However it's not so good for
shooting movie clips because a) it's 24 rather than 25 fps, and b) the rows
are read out sequentially, giving rise to the notorious "rolling shutter"
effect which causes vertical edges of fast moving objects to appear to slope
as the object has moved between the top row and bottom rows of pixels being
read. I think also the sensor uses a fairly low resolution which is upscaled
to the 1280x720 of the recorded files, instead of using the full resolution
of (part of) the sensor, so one pixel on the sensor matches one pixel in the
video file.

Do CCDs have better or worse exposure latitude that CMOS? I've noticed a lot
of cheaper cameras used for filming fly-on-the-wall documentaries have
really obnoxious crushing of highlights - shiny spots on people's faces or
bright skies - which is much less noticeable with broadcast standard
cameras. And often it's only one or two of the three colours which max out,
so the bleached parts are cyan, yellow or magenta rather than pure white
which is more tolerable.

What technology do broadcast cameras generally use nowadays - CCD or CMOS?