Get the technical stuff right and you'll find your camera (whatever it is) might be better than you ever thought possible.

From "James and the Giant Peach." A Zach Theatre Production.

I guess it's not hard to imagine that a lot of my close friends are photographers and filmmakers. In some of our down time between projects we have a tendency to meet at the local coffee shop and discuss a wide range of topics related to our work. It's nice because it provides and information feedback loop that helps keep us current. Everyone seems to have their own point of view and their own assessment of the value, and the balance of, technical and artistic considerations.

One of the discussions that came up this week concerned video cameras but is cogent to all cameras. My friend had shot some video with his Sony A7Sii camera (a really good DSLR for shooting video) and was observing that the 8 bit files from that camera were more "fragile" than the 10 bit files from his other video camera, a Sony FS7. I asked him to explain and he told me that he is able to color correct much more aggressively with the bigger files and that smaller changes to the 8 bit file cause those files to quickly "break" and lose image quality. He said that the same was true when it came to correcting exposure or lifting shadow and recovering highlights. Much more latitude for correction in the bigger camera.

As I struggled to understand why one camera could be so much better than the other I asked a few questions about his shooting habits. It turns out that he is not as concerned about getting a good white balance prior to shooting because he feels that he can correct a great deal in post processing. He does not use a light meter and has similar beliefs about exposure correction in post processing. That's fair; everyone works in a different way. But my point of view is different.

Rather than depending on the latitude and flexibility of the final files from a still or video camera I tend to take the approach that most cameras can give very convincing results if you are able to fine tune your shooting parameters to optimize your files at the time of shooting.

Whether your camera shoots in 8 bits or 10 bits as long as the files are not raw a certain amount of color shifting is permanently part of your files if you are not making custom white balances. I'll admit that I was more reticent to take the time to custom white balance with my Nikon cameras because the procedure was complex and I would sometimes forget the process without my cheat sheet. But, if you shoot a Jpeg file and the file is too blue that means some of the yellow color information has already been thrown away and the best you can hope for in post processing is an interpolated and non-linear, subjective reconstruction of the file color. You are basically trying to boost the yellow channel and replace the lost yellow; working from memory. The information is already lost. And the loss of information in one channel overloads the color balances in the remaining channels.

Remember too that color balance also effects exposure! At some point, if too much color from one channel is discarded it is impossible to get back to a neutral balance which would have been the starting point in post processing, if a custom white balance had been done.

In my workflow at shoots the color balance precedes every other step. I always custom white balance before I set exposures.

But even in the custom white balance process there is ample room for error. While a so-so custom white balance beats auto white balance in many situations the truth is that most people are sloppy with their technique here too. The problem is that people see all white as "white." They aim their cameras at typing paper, seamless backdrop paper, a white cotton shirt, white paint, white boards and tons of other "whites" which have UV brighteners, which fluoresce, which have various color casts, etc. The use of UV brighteners makes paper look brighter and more highly reflective but it also causes magenta and purple color casting. Some papers are warm and some are cold in color. White boards have a lot of blue included in their spectrum which makes them look "cleaner" to the human eye.

The solution is to use known targets for WB that are designed with neutral white in mind. The use of the same target for every situation gets you a giant step closer to consistency and color matching between shots and between takes. Whether you use an Expo disk (lens mounted white target diffuser) or a Lastolite pop-up target or a Macbeth card, or some other known target engineered for neutral response your use of a consistent target will eventually give you greater and greater confidence in getting good white balance and will make your time correcting color in post much more enjoyable.

Buy a good white target and your camera becomes more color accurate than a more expensive camera that is poorly white balanced. Neutral is nice. It's one way of being happier with the camera you already have in your hands.

The same thing is true about exposure. The closer you get to optimum exposure the better looking your final files will be and the less work it will take to get them all to both match and show good detail in highlights and shadows. A camera with a limited dynamic range is scrupulously set to a correct, metered exposure will have more overall latitude than a more expensive camera that is set up to over expose or under expose. And even if you can "lift" the shadows with that miraculous Sony sensor you are losing detail and potentially introducing shadows banding whenever you make the lift.

I tend to use a meter because I trust an incident meter more in tricky lighting than the histograms in most cameras. And I trust the histograms in most cameras much more than I do the LCD review images. But my latest technique for good exposure setting comes from having worked a lot in video lately with cameras that have zebra stripes. I set the cameras I use to have the zebras indicate when a highlight is at 100% or higher. I aim the camera at the white balance target placed in the plane where I'll have my subject. Then I shift exposure settings until I see zebras. Then I bring down the exposure until the zebras on the white balance target just disappear. At that point I know that my whites won't burn out and that I've exposed as brightly as I can without the danger of overexposing my main subject.

A perfectly white balanced camera, set to the optimum exposure will yield the widest range of tones and the best image quality, regardless. If you have a better camera then the same holds true. The tighter your command of technique the better than camera becomes.

Once the essential camera parameters are set you are then welcome to knock yourself out and be the beret wearing, espresso sipping, monocle adorned artist you always knew you were....

Next up I guess we should look at working in a location with mixed color light sources. We've got a plan for working with that as well.


Mike Rosiak said...

So, THAT'S why, when I'm too lazy to go get the white target, and use a piece of "white" paper instead, the resulting colors sometimes get weird.

Thanks, Kirk. One of a number of reasons I read your blog every day.

Brad Nichol said...

So true Kirk, it seems many shooters of both stills and video miss the concept of getting things nailed up front. I always tell my students that its pretty hard to be creative when your fighting the gear and technical limitations (of your own making).

A couple add ons regarding colour reproduction, I have always found it way easier to edit the files for good colour reproduction if your WB is spot on, not just because you have better data (in compressed files) but also because it can be tricky finding the right adjustments in post as you lack the reference point of the original scene and your eyes and brain can play some crazy tricks on you once you are sitting in from the screen (or maybe that is just my brain and eyes messing up).

A little more off the wall and something very few photographers have ever explored, when shooting RAW stills it is possible via lens filtering to even out the native exposure across the three colour channels, exposure times become far longer but the improvements in detail, colour quality, noise, DR and file flexibility are very significant. Not easy to do, each camera is different in how it responds and it takes a lot of sorting with the RAW convertor profiling initially but having done this for many years I can say with confidence it is the ultimate technical tweak. (PS: This can also be applied to compressed video files as well)

My point is there is much more on offer even with pretty average cameras if the shooter knows where to look and takes the time to optimise things. In all honesty I think the improvements in gear have allowed quite a lot of laziness to creep into the system.