Monday, September 01, 2014

The Redemption of High Dynamic Range (HDR) Software

Joshua tree in Hidden Valley, Joshua Tree National Park
When I captured the image above in early 2009, I used a Canon EOS 40D.  Although that was the first Canon camera marketed as producing 14-bit RAW files, it wasn't always clear from the results that it was producing the implied 4X more color resolution compared to prior models producing RAW files with 12-bits of information.  This is the original single exposure image, fully post-processed recently in Adobe Lightroom 5.  In that single exposure result I was frustrated by the relative lack of detail in the shadows, and the highlights are lacking in detail as well, so the dynamic range, the ability of the camera to capture a wide range of bright to dark light values, is clearly inadequate.

Fortunately the image was captured in a 3-exposure sequence, so as I revisit the images from that day now, over 5 years later, I can try post-processing it using a current version of Photomatix HDR software which offers a "natural" mode which produces fewer artifacts than prior versions did..  One thing that is clear is that there is a significant amount of shadow and highlight detail present in the scene which is brought back into the HDR result.

3 exposures post-processed in Photomatix HDR software

I had been unable to produce an acceptable result for this image in 2009, but using current tools, significant highlight and shadow detail can be recovered.  High Dynamic Range software is finally getting to the point where it can produce high dynamic range.

Six days before I had captured this photo, I had written a blog post including the following:
"Many people vilify HDR; I don't get it. Most people play guitar poorly, but that won't keep me from enjoying the work of many talented guitarists. Of course everyone's entitled to their opinion and their own tastes. If classical music fans want to say, 'Ugh, I think I hear a guitar in that piece!', or photography fans want to say 'Ugh, Galen Rowell used graduated neutral density filters!', that's their privilege. Surely HDR software will get better and better at expanding dynamic range while producing unobtrusive results, and as that value is delivered for more and more shots, I'll have terabytes of exposure-bracketed images to draw upon."
Why Would Anyone Use HDR? It's Unreal!
While the degree to which the HDR processing itself is still noticeable is open for discussion, I didn't care for the original which was overly light and dark at the same time, so this strikes me as an improvement.  It is also a good example of that concept I proposed which proposes that future advances in software may help us overcome current limitations in hardware, provided that you record more data than your camera can capture in a single exposure.  The way to do that is to capture an exposure-bracketed sequence, where you capture both darker and lighter exposures than your best attempt at a single exposure.

At that point in 2009 I was using HDR software roughly 80% of the time, in spite of its crude state and sometimes objectionable artifacts.  Shortly after upgrading to a Canon 5D Mark II, with a full frame sensor and much better dynamic range,  I was able to quickly drive my HDR usage down to 10% and then 2-3%.  HDR could still rescue images which could not be salvaged in single exposure form, so it remained one of many tools at my disposal, but it became more of a tool of last resort than a key piece of my workflow.  

Unfortunately by that point the use of HDR had developed negative connotations with many photographers, so in 2011 I felt the need to explain my rationale for using it at all:
"Some photographers have fallen in love with High Dynamic Range (HDR) post-processing, producing dramatic but strange results. Other photographers dismiss the often wacky-looking HDR results as 'technicolor vomit' and note that any monkey can move a slider in software to make a scene look strange, the talent lies in making a single, flat camera exposure look more like what we experienced onsite. Unfortunately, the range of light present, the dynamic range of the scene, is often far beyond what a single camera exposure can capture. So like so many polarized debates these days, the prudent path may lie somewhere in between. " 
HDR Isn't Just a Crutch, or a Crime 
As I look back now, with improved HDR software providing even more useful utility, as I try to process photos from my pre-2009 cameras I still have challenges producing excellent results from some of the lighting conditions I found myself shooting in.  So although my own pendulum of HDR use swung from strong support to a bias against it, as my use is rising again it's still a centrist view: I'll use it when it's useful, and it is becoming more useful.

Merced River Calm
HDR 2014, Canon Digital Rebel XTi photo captured November 2006
If you decide to buy Photomatix, you can get a 15% discount by using the coupon code JeffSullivan when you by it from its publisher HDRsoft: