Hello, I realize tests of cameras and I want to determine the dynamics of the sensor with RawDigger. Here's how I do it:
I shoot a gray and uniform scene. For the first shot I let the camera automatically expose for a VR Exposure = 0. Next i surexpose the target by EV=+7. Next i shoot i dark with the lenscap at 1/1600 s f/16 to have a black and quick exposure
So i have
- 1 shot at EV=0
- 1 shot at EV=+7
- 1 shot darknoise (1/1600 s with lenscap)
I try to mesure the Sony RX10
I open the raw file with rawdigger to mesure the darknoise and with the histogram i read the max of the statistics
green 1 44
green 2 52
Next, i open the raw EV=+7
green 1 15796
green 2 15796
All the channels are at 15796
to evaluate the dynamic range i make this calcul : Dyn Range = (log (B) - log (A))/log2 where B is the result at EV=+1 and A dark noise
i found this :
Green 1 8,46723501070998
green 2 8,24683193431926
Do you think my calcul is correct ?
Next i calculate for EV=0 and take the min + the max of the statistics / 2.
For the surexposition i calculate (log (B) - log (A))/log2 where B is the max for EV=+7 ans A the result for EV=0
i found this
So for me, the max surexposition for the RX10 is 2,3EV.
But when i shoot a targer with +2EV i can't recover all the detail in the high level. The max of overexposure is +1,7EV
How can you explain this ?