more pixels are better!

Started Dec 14, 2008 | Discussions thread
Graystar Veteran Member • Posts: 8,373
Re: more pixels are better!

Andrew dB wrote:

Graystar wrote:

As with all these kinds of technical nuances, the true answer is long
and complex.

Read noise ought to be the same regardless of exposure duration since
the read is an event occuring at the end of the exposure. Thermal
noise will become more significant as exposure length increases and
for constant temperature is linear but increases by a factor of 2
every 6-7 deg C (in CCDs, not certain if CMOS follows the same
rules). Unless you are dealing with exposures in multiple seconds or
minutes, thermal noise shouldn't be an issue.

Read noise for CCDs also increases with temperature and increases as
readout clock frequency is raised to reduce read times. For this
reason, low noise scientific cameras often have very slow readouts
that take many seconds to read each image from the chip.

See...long and complex

Sorry, meant to change "read noise" into the all-encompassing "sensor noise" like I did later in the post, but I let a couple slipped.

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