mfurman wrote: ejmartin: ISO 1600 read noise is about 4.4-4.8 RAW levels, or about 2.2-2.3 electrons -- better than the 50D on a per pixel basis, about the same on a per area basis.
Do not mean to focus on that too much but would you be able to say if, as far as noise is concerned, 7D is better than 5D mkI? Why does 5D dynamic range of 5D is so poor at low ISO?
Thank you
Michael
As far as electronic read noise, the 7D is substantially better than the original 5D at both low and high ISO. Note however that the 5D has about two and a half times the sensor area and so for a given Tv/Av will collect that many times more photons -- photon shot noise at a given scale in the image gives about a 4/3 stop advantage to the 5D (perhaps a bit less, because the 7D seems to have a somewhat more efficient sensor).
Low ISO DR is limited by the electronic read noise added after signal amplification, in the ISO amplifier and ADC. Cleaner amplifier/ADC or other methods of reducing this noise have the potential of gaining of order two stops in low ISO DR (according to the engineering definition of DR). This is for instance a large part of the reason why the D3x scores so well in low ISO DR in DxO\'s testing.
Oct 16, 2009 at 09:10 AM
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