At the risk of starting a thread that will possibly degenerate into name calling and acknowledgement that DxO are the masters of measurement (
), I'll expand here on a recent post I made regarding an article in UK magazine, Amateur Photographer.
Written by Bob Newman, a Prof. of Computer Science at the University of Wolverhampton, he talks about the changes in approach taken by Canon and Nikon to their analogue-to-digital converters (ADCs).
I'll paraphrase the salient points:
Previously, Canon's approach resulted in lots of residual noise when using low ISOs compared to Nikon. The reason being that Canon's ADCs were not on the same chip as the sensor. With a limited number of communications channels between them (usually 16 in the top-end bodies), the camera had to process the data very quickly before moving on to the next frame.
There is a trade-off between speed and noise. The read noise would lurk in the shadows and when boosted, would offend the eye (my words, not Bob's).
Nikon had taken the route of placing the ADC on the same chip as the sensor which allowed them to have more of them; 24 on the D4 and thousands in other cameras which used a column-parallel arrangement allowing the ADC(s) to be built into the sensor array. This allows for slower processing and lower read noise.
At high ISO, the implimentation of the ADC is less critical as the boosted signal is much greater than the electrical noise inherent within the circuitry. Therefore Canon's high ISO performance wasn't held back but low ISO had limits to the dynamic range.
Now with the 1DX2, Canon have gone the route of using these column ADCs to get improved low ISO DR whereas Nikon have gone the opposite way to give the user lower DR at low ISO but things improve once you get to high ISO.
So there we have it. The 1DX2 kicks ass at low ISOs but the D5 will take the DR lead at high ISO. Recent examples on the web show Canon's high ISOs are quite smudgie compared to the D5.
Now over to DxO for their take
Written by Bob Newman, a Prof. of Computer Science at the University of Wolverhampton, he talks about the changes in approach taken by Canon and Nikon to their analogue-to-digital converters (ADCs).
I'll paraphrase the salient points:
Previously, Canon's approach resulted in lots of residual noise when using low ISOs compared to Nikon. The reason being that Canon's ADCs were not on the same chip as the sensor. With a limited number of communications channels between them (usually 16 in the top-end bodies), the camera had to process the data very quickly before moving on to the next frame.
There is a trade-off between speed and noise. The read noise would lurk in the shadows and when boosted, would offend the eye (my words, not Bob's).
Nikon had taken the route of placing the ADC on the same chip as the sensor which allowed them to have more of them; 24 on the D4 and thousands in other cameras which used a column-parallel arrangement allowing the ADC(s) to be built into the sensor array. This allows for slower processing and lower read noise.
At high ISO, the implimentation of the ADC is less critical as the boosted signal is much greater than the electrical noise inherent within the circuitry. Therefore Canon's high ISO performance wasn't held back but low ISO had limits to the dynamic range.
Now with the 1DX2, Canon have gone the route of using these column ADCs to get improved low ISO DR whereas Nikon have gone the opposite way to give the user lower DR at low ISO but things improve once you get to high ISO.
So there we have it. The 1DX2 kicks ass at low ISOs but the D5 will take the DR lead at high ISO. Recent examples on the web show Canon's high ISOs are quite smudgie compared to the D5.
Now over to DxO for their take