I'm perplexed be the exposure settings, in relation to the scene, when attempting to create a balanced/calibrated scene (eg: grey material + light + exposure + render = grey is grey). Although I can get the desired grey, it's just that the the exposure (or something) is just not behaving as I would expect. I don't believe this is a gamma issue, and I'm reasonably confident with V-Ray, but this is weird....
The scene has:
VRaylight Dome, Multiplier 30, color is 255,255,255
VRay Plane: Simple Vray Material (default), 128,128,128
VRayLightMeter: 1m x 1m, Total Illuminance, Lux = 7970 (EV 11.5)
Background: color 128,128,128
VRay Exposure Control: Photographic mode, Shutter speed 125, f-no 9.8, ISO 100, White balance = Neutral
VFB, Pixel Information Color (8bit): Reads 128,128,128 (so that is fine but...)
My query is: To maintain a grey of 128,128,128 why do I have to set the f-number to 9.8 ?!
I assume that if these elements are to behave logically together; in a physically accurate approximation, should they not require an f-stop of 12.5 (or at least something less arbitrary than 9.8) ?
note: Additionally, the Render settings follow a LWF, and the V-Ray Environment skylight override is checked and set to black, so the background doesn't contribute light.
So, can any shed some light on this?
(oh no - unintended poor pun!)
If your wondering why it matters to me, this is a test scene I'm doing to consolidate my understanding of these components together. So I can confidently light and expose my scenes with real world parameters throughout the workflow. An f-stop of 9.8 in this scenario, just doesn't fit my understanding at the moment. I'd hate to find out the VRay exposure, lights, or lightmeter are unreliable, so hopefully I have just miscalculated.