When I was using my camera, I set it to aperture priority mode. I noticed the exposure compensation dial. When I turned it from +1 to +2, the final photo became much brighter. Now I understand that this 'stop' actually represents a logarithmic scale.
nickjiang2378
How do you determine how much exposure should be considered "normal" vs +1 or -1?
kujjwal
Is there an intuitive explanation why exposure is scaled logarithmically as opposed to linearly or by some other factor? In phone camera settings for example, it seems somewhat unintuitive to have such wide deviations in brightness when changing exposure by small amounts. Do we use this formulation due to convention or is there an intuitive reason why exposure should scale logarithmically?
jinweiwong
@kujjwal I think this was mentioned in lecture but it scales logarithmically because our eyes perceive brightness on a logarithmic scale. So a +1 stop would be "twice" as bright and a -1 stop would be "twice" as dim. But it is interesting how our eyes have evolved to perceive brightness on a logarithmic scale, maybe it is to accommodate for the large variation in brightness in everyday environments?
llejj
Light and sound waves have some similarities. It's interesting that our hearing also scales logarithmically (the decibel scale).
emily-xiao
I thought it was interesting that natural perceptual scale of exposure is logarithmic so I did a little research. More info about Weber's Law: https://www.cis.rit.edu/people/faculty/montag/vandplite/pages/chap_3/ch3p1.html. It suggests the just-noticeable difference in a stimulus is proportional to the magnitude of the stimulus, hence why exposure doesn't scale linearly to the human eye.
AnikethPrasad
I would assume that the "normal exposure" for an image is what appears to be the most realistic. What are some of the strategies used to evaluate the lighting when calculating exposure?
ElShroomster
After reading and analyzing these slides, I notice that exposure is a really big issue when it came to my highschool/middleschool photo ids. A lot of the time, the IDs would either be too bright or too dark to be recognizable. Thinking back on that looking at this slide is kinda funny.
When I was using my camera, I set it to aperture priority mode. I noticed the exposure compensation dial. When I turned it from +1 to +2, the final photo became much brighter. Now I understand that this 'stop' actually represents a logarithmic scale.
How do you determine how much exposure should be considered "normal" vs +1 or -1?
Is there an intuitive explanation why exposure is scaled logarithmically as opposed to linearly or by some other factor? In phone camera settings for example, it seems somewhat unintuitive to have such wide deviations in brightness when changing exposure by small amounts. Do we use this formulation due to convention or is there an intuitive reason why exposure should scale logarithmically?
@kujjwal I think this was mentioned in lecture but it scales logarithmically because our eyes perceive brightness on a logarithmic scale. So a +1 stop would be "twice" as bright and a -1 stop would be "twice" as dim. But it is interesting how our eyes have evolved to perceive brightness on a logarithmic scale, maybe it is to accommodate for the large variation in brightness in everyday environments?
Light and sound waves have some similarities. It's interesting that our hearing also scales logarithmically (the decibel scale).
I thought it was interesting that natural perceptual scale of exposure is logarithmic so I did a little research. More info about Weber's Law: https://www.cis.rit.edu/people/faculty/montag/vandplite/pages/chap_3/ch3p1.html. It suggests the just-noticeable difference in a stimulus is proportional to the magnitude of the stimulus, hence why exposure doesn't scale linearly to the human eye.
I would assume that the "normal exposure" for an image is what appears to be the most realistic. What are some of the strategies used to evaluate the lighting when calculating exposure?
After reading and analyzing these slides, I notice that exposure is a really big issue when it came to my highschool/middleschool photo ids. A lot of the time, the IDs would either be too bright or too dark to be recognizable. Thinking back on that looking at this slide is kinda funny.