Hongji Wu

Thanks for the contribution，Guy！I actually understand the logE curve, but you've still done a great job for explaining it in details! the mid gray doesn't need to exist in the actual scene and can be imaginary. 6 months ago I was so messed up in my brain... :)

OMG, after 6 months this thread seems to become a battlefield... B) Anyway, thank you all for the response!

thanks again Adrien!

Thank you for your reply Adrian ! I seem to understand a little bit more, to put it in my own words: incident meter basically collects the incoming light from all direction and get the data of the intensity, they don't need to know what's a darker gray or a lighter gray because it's changing, but the middle point of 18% gray (which is unchangeable as a fact of the reality) is fixed, and that acted as a baseline of calculation. So as long as the reading of the incident meter makes the camera replicate the mid gray tone from the mid gray tone in the actual scene, other lighter or darker areas falls into its place naturally. Am I correct about that ?

It's a stupid question, but i haven't find any satisfying results on the internet, so the idiot starts to ask! :) there's something i don't understand about incident meter: We know that when we use the reading from the spot meter, the measured area will be rendered 18% middle gray regardless of the actual reflectance of the area, so we open up or close down the aperture and get a proper exposure. But when we use an incident meter, which takes an average reading of the incoming light onto the object, we don't have any actual reference or benchmark like 18% grey for it to calculate, how could the meter "know" which part is lighter and which part is darker? I see some people answered "using the reading from an incident meter makes a gray card in the same light settings falls into ZONE V" but i got more confused because it kinda explains nothing... Let me be more specific, E.g. How did incident meter calculate the light distribution on an Caucasian face and gives out a reading that replicates the same tone as we see? there may still be misconceptions and errors in my understanding of zone system or both meters, can some one explain it to me in an easy way? That would be very helpful, thanks! :lol: