Over on DPR, when I was talking about the noise tests on the D5 and Z7 that I posted the day before yesterday, I remarked that the camera sensitivities appeared to be different, referencing a study I did on the Z5, a7RIII, and D850 some time ago. In that post, I found the D5 to be more sensitive than the D850 at the same ISO setting. I remembered the results wrong, and a user called me on it. Love it when someone uses my own data to prove men wrong.
I decided to directly compare the D5 to the Z7, using this protocol:
- Camera on tripod aimed a backlights shade 2 feet away.
- Sigma 35 mm f/1.4 F-mount ART lens
- ISO 100
- 1/1000 second
- 4 shots with each camera
- Lens focused on infinity to blur shade
- Data analyzed in RawDigger
- Selection in center of images
- 600×600 pixels for D5, 900×900 [ixels for the Z7, to keep[ the FOV the same
The green channels have just about the same sensitivity, but the red and blue channels in the Z7 and more sensitive by about a fifth of a stop.
I think these small differences are of academic interest only.