Thoughts On Image Quality II

In the last installment on the topic I led off with an image with direct sun, average room bounce-back, some sky without any modifiers. Your typical garden variety scene presented to you day in and day out. Shot wide open with no DR tricks and IQ was fine in my book. I ended that post with an image similar to the one at the left with lots of what could be considered a flaw. A bunch of contrast reducing flare. Something I play with here and there if the context feels right. I would argue that in many cases the fact that I can provoke flare of various types, characters, and intensities can be considered quality enhancing. It certainly imparts a feeling that is different than perfect contrast. It's just another tool to manipulate in the infinite variety of variables possible in-camera.

If there is way too much flare no big deal. Camera angle, how much of the light source you include in the frame, your aperture, flagging some of that source off the front of the lens, and a million other things dictate how it actually looks. I shot a couple dozen shots in fly-on-the-wall mode here and there all with variations in flare from horrible no contrast to fairly mild like the one on the right here with not a whole lot of control over where I was standing, where Mika was, or anything else about the scene. I had to stay out of the way of the session in progress.

The one at the top was actually shot closed down a stop at f/2. The latter at f/1.4 to grab a bit more flare-y-ness with this framing and angle. The variations I have go from A-Z. If I can do it while skulking around anyone can control this without the need for some esoteric super expensive glass. Would I want a lens that offered exactly the same rendering across every scene no matter how it was used? Probably not. I like the level of flare provoked in both shots. Different but both actually add to the image quality in certain ways. Do you define every image you take based on some arbitrary contrast rendering? I certainly don't. Here's another with even a bit less flare but I still like that halation on the right.

I'll bet you can guess where the opposite halation/flare is coming from on the left too… Another window. Truth be told, if I could move a hair closer I would have as a variation. Too bad I would have been in what could be considered the photographer's session working space. I did mention last time that the light coming in the windows was a mix of sky and direct sun right? How can this be? They probably look a bit different than your direct sun shots. Why is this? You definitely know the answer already but it's control of the lighting ratio of the scene. In this case that's done with a setup I suggested based on what the photographer wanted from a look point of view. Here's the setup…

You can see the direct sun from this angle clearly. That thing on the right with the sandbag in front is a 4x8 hunk of foam insulator board from Home Depot that's standing in until our foamcore order arrives. It's less than $10. You can see how different the lighting ratio is where Mika is situated compared to the rest of the scene. With something as cheap and simple as a reflector you can pretty much make any light you want. Want more drama? Move it back. You can use them as flags too – more on that another day though. Here's a quick snap without all of the context that's a bit more dynamic based on my suggestion that the photographer try a couple with Mika moving a bit. You know that's my thing right? Hope they worked out for him.

What, you don't have a reflector or you left it at home, or someone stole it? Just move your subject around. Works the same. Here's my point regarding image quality; The notion of some sort of magic dynamic range improvement noise performance, minor bump in lens resolving power, MTF, Auto-HDR, etc, etc is absolutely not going to absolve anyone of paying attention to the scene, reading what's going on with the light, making decisions on how to use that light, or modifying it. All of this stuff can go very wrong not because the image quality isn't good enough but because of lack of attention, lack of decisions, or just having too narrow a definition of the notion of image quality fueled by idiotic discussion in the interwebs.

Grabbed this one on the fly as the photographer was changing up his gear for a different setup. Note that the whole f/1.4 thing plays completely different if you include more variance in depth in the frame. Obvious but worth mentioning again. As for wide open IQ… meh. I'm good with this. I could make a print of just about any size from this from a sharpness point of view. Also note that Mika is a bit farther forward away from that reflector a bit in this shot. Big difference in ratio but still in the realm of what I will call photographic-medium rendering range. No matter what your camera actually captures for you to muck around with as you push decisions down the road you are still left with the realities of rendering it on a screen, or a piece of paper, or whatever to actually view it. This is actually the constraint when it comes down to it.

Trust me you are not going to want a camera that captures everything at crazy low contrast and then just dump that out on a piece of paper. That's actually pretty easy and very ugly. It's all about scene contrast – scene being flexibly defined as what you choose to be framed and what part of the scene you would like within photographic medium range when it's rendered to view. If parts of the scene fall out of that then making decisions on how that will play from an artistic POV is pretty important too. The lighting ratio in that last scene was just about perfect as defined arbitrarily by Nikon's Matrix metering. If you feed stuff like this in it does a great job… perfect. It all fits in Nikon's definition of the way the world should be.

Next up we'll talk ISO, noise, etc, etc and mix in some views of what would be considered horrible shooting conditions, lighting ratios, and no ability for me as fly-on-wall/coach/assistant to influence those for my BTS shooting. Just as an aside. I actually added fake film grain to all of these shots just to give them a hair of a more casual feel.


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