Hi guys.
I was doing some tests to determine what ISO to use in a light meter to be able to prelight without using the camera as a tool.
At this point I am not interested in the noise level, nor the dynamic range.
I just want to have a reliable instrument that when you expose an 18% gray and analyze it through the False Color of the Alexa Mini, get the green color that corresponds to your scale.
Perform the tests with two different camera bodies and with two different lens sets. Before the tests, perform a factory restet of both camera bodies. I used a spotmeter Minolta F and the Sekonic L758Cine light meter with factory profiles and also with the profile created for Alexa by Ryan Waters (http://www.ryanewalters.com/SP/sekonicprofiles.html) and original (and clean?) gray card by Kodak.
In all cases to obtain a parity between the light meters and the Alexa Mini, I had to use the light meters with a sensitivity between a stop and a stop and one third above what I used in the camera.
For example, if an EI 800 was set on the camera in the light meters to match the reading, I had to set an ISO between 1600 and 2000.
I wanted to know your opinion, if this is the usual thing or I have missed something in the tests.
Regards