« on: September 29, 2014, 04:52:27 PM »
I still don't understand why there is controversy....
For some people, the current crop of Canons have enough DR.... and they are happy. For others, they do not and many of them are frustrated with waiting.
Anyone else remember when digital cameras shot 16 color jpgs? Then we went up to 8 bit colour depth... then we went to 24 bit color depth (RGB at 8 bit D/A)... then we went 10 bit A/D... then 12 bit... and we have been stuck for an awful long time at 14 bit... 16 bit will come someday soon for low pixel count sensors, but right now, with the full well charge of the current sensors 14 bits is enough to count every electron in the well. Extra bits will not help until there is a bigger well to count. That goes for EVERYONE! Canon, Nikon, Sony, whoever....
Yes, if we bumped up quantum efficiency a bit we could make minor improvements.... but realistically everyone is in the same ballpark and there are not a lot of differences when you have lots of light.
The real problem is noise. If your least significant bit is toggling on and off with noise, then you have 14-1, or 13 bits, of accuracy. If you have more noise and the least significant 3 bits are toggling with noise, you have 14-3, or 11 bits of accuracy...... and that is the difference between Canon and Sony sensors. Sony sensors read with less noise and because of that the signals have more range. If Canon improved their noise levels (and it is rumoured that this has happened on the 7D2) then the gap would lessen.
The reason why some people are so interested in seeing Canon shift to a newer fabrication run is two-fold. With higher resolution lithography, there is less wasted space and the efficiency of the sensor goes up (more electrons to count).... problem is, the number could only be boosted by a quarter so it will be an incremental improvement, not something revolutionary. The other advantage of the newer fabrication process is a redesign that moves the A/D onto the sensor and reduces noise that way... and it is possible that Canon could gain almost 2 stops if they did that...
So what does this mean in the real world?
For bright areas of the picture, very little.
For dark areas, quite a lot.
Let's say that you have a dark area of a picture where the lower 4 bits should be 1000. If you have 1 bit of noise on the signal those values are going to range from 0111 to 1001... not a lot of difference. If you have 3 bits of noise on the signal it will range from 0000 to 1111, a far more substantial difference and when you push your dark areas, you see the noise. Interestingly enough, for that area, the AVERAGE value will still be 1000. With advanced noise reduction software you can reduce that noise to a more acceptable range, but this adds in another processing step for the photographer and even at that, it will never be as clean as an image without the noise.
In essence, those who are clamoring for a better sensor would like to eliminate this processing step and want better quality images out of the camera..... but show me a single photographer out there, Canon, Nikon, Sony, or whatever shooters, who would be upset with their manufacturer if they were given cleaner images?
And that is what the debate is all about.... cleaner images. We all want the same thing so why are we attacking each other over this. Let's get along and try to be respectful.