Dynamic Range -- what it is, what it's good for, and how much you 'need'

Started Oct 17, 2011 | Discussions thread
Great Bustard
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Re: Funny!
In reply to FrankyM, Oct 24, 2011

FrankyM wrote:

x-vision wrote:

Great Bustard wrote:

I am not "assuming" -- I am defining "equally efficient sensors" as two sensors with the same QE, same read noise / area, and same saturation limit / area.

If these were ideal sensors, you would have identical SNR and DR for the same output size.

No, as I demonstrated upthread:

http://forums.dpreview.com/forums/read.asp?forum=1022&message=39652476

more pixels on a sensor with a given size and efficiency results in less noise and more DR.

However, in practice, no two sensors with these characteristics can be made on the same CMOS process. Thus, by definition , you are comparing apples vs oranges - if these were real sensors, not ideal ones.

Exactly!

Except I'm not comparing "two sensors with these characteristics can be made on the same CMOS process" -- I'm comparing sensors on the basis of the relevant measures:

  • Size

  • Pixel Count

  • QE

  • Read noise / area

  • Saturation / area

  • AA filter

  • Microlens efficiency

The overall trend is for sensors with more pixels, greater QE, less read noise / area, and greater saturation / area.

Now, of course, there are limits, not the least of which is diffraction. But giving that the highest resolving compact (that I am aware of) is the 15 MP G10, which would equate to a 300 MP FF sensor, I would say that those limits are rather far off for the time being.

So, where are the 200 MP + FF sensors? That is a very good question, worthy of another thread. See you there.

EDIT: Seems like the "another thread" is already under way:

http://forums.dpreview.com/forums/read.asp?forum=1032&message=39656016

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