Dynamic Range And Other Holy Grails

An eBuddy of mine asked me to write a post based on some crap that I gave him in a comment on his blog. He posted a nice pretty picture and I gave him a bunch of crap on semantics. All in good fun mind you. I wasn't trying to be mean and nasty. Rarely is that my intent. My focus was on a term that seems to have lost all meaning in internet use. It's usage is fast and loose and uttered along with a bunch of other wholesome goodness type words without much consideration. There are a bunch of them - the one I want to examine at the moment is one of those holy grails out there in photo utopia. The one the only dynamic range.

I hate this term now. I really do. I think I just might strike it from my vocabulary immediately after this post - or the next one if it devolves into a two-parter. Chuck it right in the dust bin with such dreck as capture. Dynamic range is good right? I mean why not seek gobs and gobs of it. Why can't camera manufacturers just make a god damn camera that has all of it - as in all the dynamic range there can possibly be. Is that what we want? Sure why not - heck that's the problem with digital right? Well not quite exactly as I hope to illuminate for a moment.

I have to stop and issue a warning here - this is going to be long and a bit circuitous. A long winding road of part fact, part rant, part hyperbole, and part of me playing fast and loose with dividing the world up into two camps then reassembling it and dividing it into maybe another two camps, on and on. Two camps for illustrative purposes. It's easier if you draw very hard lines in the sand and box everything and everyone into one side of that line or the other. Black and white. You've been warned read on at your own risk.

Film is great right? It has shitloads of dynamic range. Ooops not really - how about slide film? Honestly it has about 4 stops of useable dynamic range. Of course it renders stuff that falls outside of that. How come it looks so good? How come all the best shooters used it with such a limited dynamic range? Well that's easy - it has a ton of contrast in those few stops where it renders detail well which make is look good. What you definitely do not want is low contrast and low dynamic range.

Here are a few disjointed thoughts to chew on while you let the above paragraph seep into your subconscious. Photography is an abstraction. It has to be. At the end of it all we are rendering a three dimensional world onto a two dimensional surface. It's just as much an abstraction because we are rendering a world with insane amounts of contrast from the darkest to the brightest things that exist in our world onto a medium that has nowhere near the capability to be as dark or as bright at the same time and I am not even going to talk about putting it on paper - that's even worse in terms of how bright/dark paper's maximum capabilities are. Hence it's an abstraction.

Okay back to dynamic range of the capture medium. What has "good" dynamic range? Can we agree that negative film of various types has good dynamic range? I am assuming we can. Let's take black and white film - especially more modern linear response black and white film for a moment. Doesn't matter what kind or brand - it's a theoretical kind of film right now.

Let's pretend for a moment I went outside and found a bright sunlit scene. In that scene was the entrance to a coal mine that peered strait in and down into it's dark depths but no sun was shining in as it was 90 degrees off axis. So we have a coal mine - some nice landscape trees and stuff - some blue sky on a spring day - nice white fluffy clouds being lit by the sun - and finally the actual sun that we'll put in the frame.

Let's pretend I could take this film and expose it a lot. So much so that I rendered the inside of the coal mine perfectly exposed. I had the ne plus ultra of detail on a black lump of coal inside that mine. Let's also pretend that I could develop that film in such a way that I could see the actual detail of the surface of the sun as well. I have captured all of it. All the detail there is - the surface of the sun, the shadow side of a lump of coal inside the coal mine at the very very bottom of the coal mine. I have it all right there on my film. Perfectly - so much so that I actually could take that negative and print it on grade 2 paper and all of that detail would render. The absolute darkest little dot on that lump of coal would be at the paper DMAX black and the absolute brightest little tiny tiny tiny hottest atom of hydrogen that had just undergone fusion into helium was the white of the paper base. Everything else between the two points would be rendered with differing tones if analyzed. In fact so perfect there were not even two identical shades anywhere.

Is this what we want? Hell no. I will assure you this will be one ugly, unattractive print. Horrid beyond horrid. It will also be the most "perfect" but flat print ever made or conceived. We hate flat as photographers. We love our contrast - guess what guys/gals high contrast = low dynamic range. No if's and's or but's.

Okay while that little bit of embellishment sinks in I'll take you off on another tangent. I'll give you a secret. The pictures you like - all of them. Every single one digital, film, movies, whatever. There's a good chance they are higher contrast renditions of a scene that in some way has been manipulated to be of lower contrast than the real world. I am talking about the scene being manipulated not the resulting shitty "capture". This is the secret - the one all of you searching for that ultimate camera are hoping just goes away somehow. The pragmatic accept this - landscape guys use graduated filters. They have for decades and decades. Maybe centuries. Now they do the multi-expsoure thing instead if they can. The good ones usually blend them by hand not some crappy ass tone-mapped horse shit. People have been doing this for eons as well - the anal ones have done it with ruby lith masks that are hand cut in the dark room. Others of us search out little tiny pieces of the world that are low contrast scenes and use high contrast mediums to make them sing. Hollywood brings in hundreds of thousands of watts on a scene, shoots everything low contrast and ramps it up in post… On and on.

So what's all this dynamic range stuff anyway? How about digital? More is better right? Sure but at the end of it all what we are all trying to do is render a scene onto medium that has a fixed and somewhat lower bright to dark range than the real world attractively. This is the exercise and can be approached two different ways (gross division into two parts again) capture it all and figure out how to render it later in post (dark room) or manipulate the scene in such a way to make it look great on a higher contrast medium.

Measuring dynamic range is a bit tricky - don't bother. Sure you can be scientific about it. I am sure DXO's methodology is sound enough to compare one camera against the next as long as that criteria has any bering whatsoever on things that might actually affect what you make images of, how you make them, how you post process them, and ultimately how you like them to look. Too bad that's not the case - translating measurements into meaning for your pictures has always been fraught with peril. Digital for a long time as had pretty decent dynamic range from one perspective. As long as you underexpose mids and shadows you can extract an amazing amount of detail from the dank murky mess that pops up on your screen. Too bad that looks like shit. Always did and now looks a little less bad.

Don't believe me? Have a new wonder-cam. Any that are lightyears ahead of the predecessor which is lightyears ahead of it's predecessor? I do. Let's take the D600 or D800 - both at the top of the charts in dynamic range and lack of noise by anyone's measure. I will leave it as an exercise to you to prove but trust me when I say if you under-expose them at the very lowest ISO - or optimal ISO - or whatever by two stops and bring it back up in post there is a ton of noise.

Here's what's worse. The way digital works is that all those 14 bits of tones are all used up in the upper highlights - well the vast majority of them. If you start pulling shit up from the shadows you will find that you actually have not a whole lot of tones down there. The reality is you really want things that should be in the mids to be exposed in the mids - especially if you are going to increase contrast there - which is what you are going to do for a pretty picture. So what's my beef - honestly it's not been dynamic range for dynamic range's sake. I want no part of rendering detail in the coal mine and the surface of the sun. I have no interest. It's all about how the highlights look for what I want.

In a nutshell my beef was until recently that I had only two choices - under-expose my mids and boost them in post which renders sub-optimally in a lot of cases. Or lower the contrast of my scene even further for a lot of real world conditions that are not even close to being the coal mine/surface of sun kind of thing. Furthermore even when I frame and take care to make sure that everything I care about in a picture is in a nice region from a contrast point of view and highlights I don't care about are taking up only very little space they look horrid when I let them go. A situation handily rendered on negative film. It wasn't that there was massive detail rendered in a print it was just that they looked good when you did things like back light your subject with the sun. Only very recently have cameras started to approach a point where I can do things like that and not have highlight transitions look like shit. This is why I like the D600 and D800 so much. Is that because they are rated very high in dynamic range? Don't know. Don't care.

Let's take the image at the top. A challenging scene? Not really. Not a coal mine/surface of sun kind of thing in the least. Tricky post processing - nope. Honestly this is a high contrast rendition of a subject in fairly low contrast light. The scene itself as whole is actually fairly high contrast. Yep - take a look over on the right side of the frame. You see the brightest stuff - that's the sun. The real sun - not one of my fake ones. The subject is obviously in the "not sun" part of the room. Fairly large room - no close by reflectors - no scene modification. I rendered the skin on the side facing the camera extremely high - where I wanted it. I did pull the highlights back -35 in LR for reference. Look ma the highlights over there in the sun don't look like some god forsaken mess of artifacts and I can clearly see the white wall where the sun is hitting and not hitting. Good for me. I am happy. A few years ago I would have been scared to death to render the skin on my subject at this level in camera.

One more illustration as an example of extreme sensor abuse. I think I used another from this set a while ago on a different but related topic. This was early in my D600 torture testing. What if I take the same subject and shove her into that sunlight but shoot from the other side and expose it the way I would with color neg. What will happen? Well here we have it…

I pushed in so much exposure from the shadow side funny. I actually had to back off it a half stop in post using the exposure control as it was just too too light. Look what happened to the sunlit parts, the whites, the specular reflections, this was a true revelation in digital for me. It doesn't look too too bad. Forget the detail - the composition is such that even if I under exposed it the highest highlights are meaningless anyway. There's nothing to see there in terms of detail - could I extract even more? Maybe - who cares. There is plenty of detail there and all that stuff you see in the white curtains - not just the brightest spot but all of it was gone according to the blinkies in the camera and before I ratcheted the exposure down in post. Point is it doesn't look like complete digital dog-doo.

I guess it comes down to this - for me and what I want the dynamic range I give hoot about is between mid point and highlights and how when they don't fall into an acceptable range what they actually look like if I choose my mid-tone exposure to be where it "should" be. Why do I care about that? Well that has to do with a lot of the diatribe above and where I have found what I like to make pictures of and how I like to make them at least a good portion of the time.

Let me leave you with this. Another division of the world into two camps. In one camp are the fighters in a constant battle with the shortcomings of the medium no matter what it is. Whatever the state of affairs is it is never enough. They reject the limits of rendering the world without detail everywhere, some of them even relish the idea of being freed from the limits of the two dimensional rendering we are shackled with. The other camp embraces those limitations and likes infinite challenge of rendering a 3d world on a 2d surface and the abstraction that provides. They like that the camera or the material cannot render detail everywhere all at once and embraces that fact as a property of the medium.

I fall into the second camp. But what about your struggle with the highlight thing you ask. Well I over-blow that a bit. I was fine and am fine in most circumstances with modifying the scene to produce what I want. Or seeking out scenes that will render the way I want the subject to appear. Or even adjusting my outlook in such a way that I use the fact that the medium at hand cannot possibly render detail and will go black in the shadows.

It's all been done for ages - it's the secret even now. There is no magic button really. No magic answer of rendering a high contrast world on a lower contrast medium. I've used slide film - far worse than digital nowadays in terms of rendering detail everywhere. Geographic photographers used it's high contrast by embracing the way it renders in their compositions forever when making images in sunlight or they sought out conditions to shoot portraits that work well with that medium - like the famous Afghan girl (honestly don't know what all the fuss is about there). My pet peeve is that I just didn't like a set of characteristics in a limited set of circumstances that was super easy to handle before. All I wanted was what I had along with the virtues that digital brought to the table.

RB

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