1/3 under/over

[Matt Jacobs]

Really just have a random question. When can your eye discern the difference in exposure? My teacher was saying exposure 1/3 under or over is not noticeable to the eye. Would it be right to say 1/2 also isn't very different to the eye than normal? This is of course with color print film.

 

I was just curious. I never (prob have had differences in exposure ranging from 1/3 of stop) underexpose/overexpose anything by that little and if I have haven't noticed anything.

[Tom Jensen]

I think 1/3 of a stop is the first point where a light change becomes noticeable.

[Adrian Sierkowski]

Me thinks it depends on the experience of the eye, and the quality of the eye in general.

Before he died, my dad could tell around 1/3rd of a stop, but glaucoma got the best of him first, and eventually it was just mostly blobs, according to him; so maybe 'round a stop then (let's just say he used his meter a lot more as he aged)

[Saul Rodgar]

Exposure is relative to what the cinematographer decides needs to be "properly" exposed in a picture, for whatever reason. So what looks like overexposed to someone may not to someone else, to a degree, obviously.

 

Unless you are talking about exposing for absolutely proper rendering of an 18% gray card / gray scale to be viewed in lab-like conditions, I think this really falls in the subjective realm.

 

But if someone showed you a series of bracketed exposures of the same picture one next to the other, I think a 1/3 stop exposure difference would be somewhat easily identified _perhaps not by laymen, but certainly by professionals and trained eyes.

[Satsuki Murashige]

When can your eye discern the difference in exposure?

Depends on the eye in question. Owen Roizman claimed in "Cinematographer Style" that he can see a difference of 1/10 of a stop! A friend of mine who worked with Hiro Narita a few years ago said he could look at a bunch of HMIs lighting a white wall and discern exactly how much green/magenta correction each light needed without a color meter. Douglas Slocombe was famous for never using a light meter.

[Chris Keth]

Douglas Slocombe was famous for never using a light meter.

 

But I bet he asked his gaffer for a key level of X footcandles.