Do You Know What's Automated and How?

In working with students at workshops for a month, and then also dealing with some big questions that came in via email while I was off the Internet, I noticed a commonality in assumptions that I think I need to tackle directly:

       Not everyone realizes that something auto is making decisions for you

Take white balance, for example. Nikon currently has four different automatic white balances: Auto Keep White, Auto Keep Overall, Auto Keep Warm, and Natural Light Auto. Do you know how they differ? Do you know what your raw converter is going to do with each of them? Do you think that "auto" has no other consequences than for white balance?

I'm guessing that you don't. 

First of all, artificial light is different than natural light. Natural light is a form of black body radiation, which means that light spectrum is created continuously both in value and time. Most artificial or human-modified light tends to have spectral gaps and peaks, plus they often have a frequency component. I'm a strong believer that if you're outdoors during the day photographing in natural light, you should always use Nikon's Natural Light Auto. If you're indoors (or outdoors at night in a city area with artificial lights present), you can pick one of the other auto white balances, but I'd argue that you need more information and should be using that to perhaps make a different choice.

But beyond just what "auto" is doing to color information, there's the issue of histograms. The in-camera histograms are based upon JPEG settings, including white balance. I keep having people tell me that they photograph in raw and don't need to worry about white balance. They are wrong. Either that or they don't care whether the histograms and highlights displays on their camera have any accuracy whatsoever to what is actually recorded. 

But it doesn't stop there. On a Nikon we have Picture Controls (Fujifilm has Film Simulations, and every maker has their own term for their image profiling). The default Picture Control is Auto on a Nikon body out of the box these days. Auto in this context means that the camera can alter contrast, gamma (brightness), saturation, hue, and a host of other controls on its own. Like white balance, this impacts how accurate your in-camera histograms and highlights may be, but on mirrorless cameras these days, it also means what you think you see as "proper exposure" in the viewfinder may actually not be recorded that way in the raw file. Oops. 

Even the Nikon Standard Picture Control has some automatic response to it. Neutral and Flat are the best choices to avoid automation decisions on Nikon cameras.

Of course you're using matrix metering, right? Nikon's matrix metering is eerily accurate. But only to a point, and only if you know what things impact it. Matrix metering makes automated decisions based upon a great deal of inputs. Focus point, for instance. Worse still, things may change if a human is detected (Custom Setting #B4: Matrix metering face detection). 

A lot of you are using automatic ISO. This function works differently in different exposure modes, so do you know what it does in the exposure mode you use? I keep finding folk who use Auto ISO in Manual exposure mode—the only choice I think makes any real sense—who can't tell me what happens when the exposure gets outside of the parameter range they've set for Auto ISO (maximum ISO and minimum shutter speed). You've asked for "automatic," so something's going to happen ;~). 

Recently I had someone tell me that they had changed their Focus Tracking With Lock-on value while they were using 3D-tracking as the AF-area mode. Nope, they didn't. Focus tracking speed is fixed with 3D-tracking, an unannounced and often unseen change that catches people unaware.

I could go on, but I think I've made my point: you need to know what all the automation is doing and whether its going to impact other things you need the camera to do. So:

  1. Figure out all the settings you use that do automatic things in the background.
  2. Figure out whether you need that automation or not.
  3. Figure out what side-impacts the automation may have on your results.

That last bit brings us to post processing. 

Adobe and Nikon don't agree on white balance, for instance. While Adobe reads the EXIF data for white balance from your raw files, Lightroom and ACR interpret that information differently than does Nikon. Unfortunately, we don't know exactly how Adobe changes things, but you should note that the color temperature reported by Adobe products is way different than that reported by Nikon NX Studio. Something "automatic" is happening in the background.

I can tell you a bit of that, and it's not the best of stories. Adobe creates their profiles for cameras from two known-light exposures. One in carefully controlled artificial light, one in controlled daylight. Adobe appears to make the assumption that white balance is "linear," thus any temperature between those two known ones should be linearly placed between the exposures they captured. Likewise, if the color temperature is outside those two reference values, things are still assumed to be linear. 

Thing is, what do we know about differences in image sensor filtration? It predominately varies in the red and blue filtration. Even within Nikon cameras there are some significant differences. The pro bodies have tended to have slightly higher red response, the consumer bodies slightly blue response. I have to build a UniWB separately for every camera because of this. But technically, you should be profiling more than the two data points Adobe uses if you want to be even close to accurate with color in extreme lighting conditions. 

I could write a dissertation on all the "automation" that is undocumented or even mostly unknown that comes into play with both our cameras and our post processing workflows. The "average" user, on the other hand, wants to use automation as much as possible because there are too many variables that should be controlled to make you a perfect craftsperson (or deviant artist).  

Personally, I'm tolerant of some automatic bits in my photographic process, as long as I understand that they're there and I have some idea that what they're doing isn't going to contra-impact what I'm doing. 

I'm hoping that the camera companies don't think that FSP (fully self photographing) cameras aren't the real design goal in the future. While I know some of you want FSV (fully self-driving vehicles) and Elon Musk has promised you that for over a decade now, photography is personal and should stay personal. You show me your world, and I show you mine. They should not be automated to be the same.

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