Canon 1dx on par with d800,d4 and low light situations

Started Jul 28, 2012 | Discussions thread
dosdan
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Re: That's mostly a measure of read noise, not High ISO performance
In reply to Jon Rty, Jul 30, 2012

Jon Rty wrote:

Yes, but at high ISOs, doesn't photon noise outweigh read-noise even in the shadows, leaving QE as the dominant factor?

No, shot niose & PRNU are much bigger at all ISOs. Here is a spreadsheet of total noise, shot noise, PRNU & read noise for some APS-C cameras at either FWC or ADC saturation up to ISO1600. It also includes a PRNU co-efficient calculator. Uses the figures from http://www.sensorgen.info . The values are in equiv. sensor electrons. User-input areas are coloured yellow.

Be aware that non-correlated noises add in quadrature. So, if at a certain ISO, Noise A is 100e- & Noise B is 50e-, the combined noise level is 111.8e- which is the square root of (100^2 + 50^2).

Note: the K-5 has a different X-axis range because its base ISO is ISO80.

http://dl.dropbox.com/u/51093924/Noise%20Components%20Contribution%20at%20Saturation%20v2.xls

Dan

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