The camera tests that are linked below were shot at Axis Films Shepperton Studios facility and at 24/7 Visual Impact
All Charts were lit to T2 and T22 at an ISO of 320
All cameras were fitted with Zeiss lenses
With the chart lit to T2 a series of exposures were made at half stop intervals to T22
The with the chart lit to T22 a series of exposures were made at half stop intervals to T2
All charts are clearly identified with base stop and exposed stop
All the film was shot the same way but then scanned on a variety of scanners, once again these are clearly identified.
The graphs chart the 8bit readings of the 18% grey section of the chart. These have possible values of 0-255 some cameras are limited to a slightly smaller range, TV safe.
The area in the 100-150 is the mid-grey region, if the middle of this part of the slope is directly above the 0 exposure position then the camera or stock is ISO 320.
If that point is plus one then the ISO is 160 and if minus one it is ISO 640, the plus/minus relating to the exposure relative to ISO 320 "normal"
Clicking on any of the small reference jpeg's will get the full res DPX or TIFF for you.
Matched files, several results on a page, you'll need to download the full files for this to make sense
7212 on Arri Scanner - Spirit 4K - Northlight - Cintel DIttO
7229 on Arri Scanner - Spirit 4K - Northlight - Cintel DIttO