About Light Tone Curves and Exposure

As photographers we have to be into light and how it works and more importantly how it looks. No matter if you shoot film or digital this is pretty important. I write a lot about shooting StupidCrap™ in a tongue in cheek sort of way. For the most part us photo-nuts do shoot a lot of stuff that never sees the light of day - or at least it shouldn't but that's debatable with instant worldwide publishing direct from your camera to the web. I am a big fan of playing and shooting subject matter that has no purpose other than visual exploration.

I do it all the time. After a while this usually has some sort of purpose - even if it's not readily apparent to anyone other than you. That purpose can shift and mutate and change depending on what's on your mind at any given point. In my case one of the things that I have continuously done for more years than I care to remember in one form or another is to keep a little note book of light. That really started way back when testing various black and white film and development for purely technical reasons in terms of process calibration.

Over time it mutated to a more aesthetic purpose and then back to a technical analysis of why certain things looked the way they looked. This endeavor never ceases to amaze me in little ways as well as big. It continues to vacillate back and forth between aesthetic an technical as the two are somewhat intertwined in this photography endeavor.

Lately I tend to use my Fuji X100 as my little visual notebook. Every once in a while I actually shoot a worthwhile subject with it as well. It's small enough to have with me all of the time and has quality that doesn't feel too compromised. The device doesn't really matter - cell phone - whatever. The image at the top of the post is pretty interesting - at least to me and I thought I would share it along with a couple of thoughts on things that could be learned from it. I shot it while having a short cigarette/coffee break and noticed something that is pretty important technically and visually that sort of floats my boat.

Take a careful look at the light and specifically the shadow values created by the hard source (sun) blasting through railing balusters onto a light dusting of snow and concrete. Notice anything strange and wonderful? Probably but if you can't put it into words here it is…

One would expect the highlight and shadow values on the two surfaces to have different values but unless you have been looking at this stuff a long time you might not expect the relationships between highlight and shadow to be as different as this image shows. Especially between something as similar in the mind as light colored concrete and snow in the same light with the same fill ratios. Interesting huh?

This will look this way to one degree or another no matter whether you shoot film or digital. It has to do with tone curve shape as mid tones go into highlights and how real light is compressed for display on a medium of lower contrast. That's not really important - how it looks is quite important. How it looks is also completely dependent on how you choose to expose. Choice being the key word. The shadow highlight values would be much closer to the same if I chose to put the snow more toward the mid-tones. I thought this was interesting since perceptually the two surfaces are pretty darn close to each other when viewed directly in person. Maybe a stop different in terms of reflectivity - if that.

Notice how that ratio varies between the wet and dry parts of the concrete as well. Pretty amazing huh? The purpose for me of doing stuff like this doesn't end with - "pretty cool huh?" For me it serves to inform and refine how I use light and exposure in both natural light conditions and notice things and react to them when shooting a real subject. It also informs how I might choose to light something and how I might expose it when I create the light myself.

What kind of visual notebook do you keep? Have you ever gone back and looked at what interested you in the first place when you took the shot. Brick walls and "is my camera working properly" types of shots not withstanding - looking at other apparently purposeless shots from your past that you somehow just like can be pretty informative and educational in retrospect.

More later. I make all kinds of little things in my visual notebook that are pretty interesting to me.


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