Luminance should not change much with distance, unless the meter is starting to read past the screen edges or you are not aiming it at the same point on the screen, like directly at the middle where most projectors are brighter. Or if the view angle changes with distance and you are not using a utility gain screen.
It may drop a slight bit with distance because you are reading at a farther radius from the screen center of the screen which is usually brighter than the edges, so the overall reading will be slightly dimmer, but it shouldn't be more than a couple percent at most.
There should only really be 3 things that matter for ideal meter placement. Keeping the reading out of the shadow, maximizing luminance, and reading the screen from a similar angle as the viewer (mainly if you screen is not not a perfect 1.0 utility gain screen). So that you are calibrating it for how the viewers see it.
There is no reason not to use full screen patterns and would be necessary if you are placing some meters far away anyways.
For gamma it doesn't matter the iris position, so open it to maximize brightness. For color and grayscale iris can affect it, so use the iris position that you will be using.
My screen is 65" tall and I mount my i1D3 about 7ft back which lets me mount it eye level and pointed at the center of the screen with barely any upward angle on the meter. At 7ft it also casts no shadow on the screen whatsoever.
Moving it closer does not give me any brighter reading.
For my i1 Pro 2, I mount it in the same place, mainly because I am usually using it to create a correction matrix for my i1D3, and it's best to have both meters in the same position when doing so.
Otherwise I have put my i1 Pro 2 at about 12ft before basically right in my main seat and the luminance readings weren't any dimmer. The i1 Pro 2 has a pretty narrow field of view.
Last edited by SirMaster; 11-09-2019 at 05:00 PM.