Lightroom 4 and HDR

A photo friend told to me once, that HDR is like alcohol. "You need to get horribly drunk a few times to understand what’s wrong with that" he said. Some people may get hooked, sure, but most find their personal threshold and then use HDR occasionally in socially acceptable doses.

Lightroom, however, is like crack for photographers. You had no idea what all the fuzz is about, but once you tried it there is no escape. It inevitably becomes the centerpiece of your entire workflow. Suddenly everything seems so easy, effortless and fun. Photographers in an advanced state of addiction don’t go out without their Lightroom library, even if it’s just on the iPad.

And now Adobe Labs cooked up Lightroom 4 beta.

This new version will let you
  • apply more targeted edits to selected areas,
  • manage videos (even edit them to a degree),
  • trace your steps on a GPS map,
  • create and order photo books from Blurb,
  • soft-proof prints.

All the features above are well documented in the DPReview hands-on Preview and Ian Lyons’ Digital Darkroom. I'll just concentrate on the part relevant to HDR.

What's with HDR and Lightroom 4?

Specifically, what's with developing RAW files to be merged to an HDR? That's still the primary use case, LR4 still doesn't support HDR directly. But it does have a new color engine under the hood, with better quality.

So, it's better?

Yes and no. Adobe shot slightly past the goal line. It’s true that Lightroom 4 extracts more dynamic range from a RAW image. And it's true that this is absolutely awesome for single shots. But when you have an exposure sequence, that's actually counter productive. For HDR the overexposed shots are supposed to look like way, because clipped highlights signalize the HDR merger to look at the next image for better data. But when every image is individually optimized with a smooth film-like shoulder for the highlights, that is throwing a big monkey wrench into the inner mechanism of HDR merging.

Show me!

Okay, here's a bracketing sequence is in 1 EV steps. If you drop the second and fourth shot, that would represent the typical 3-frame +/- 2 EVs most people shoot. No, it's not a perfect sequence; it just barely covers the dynamic range of the scene. In Lightroom 3 it takes some dirty tricks to squeeze the last bit of highlight data from RAW headroom of the first image.

In Lightroom 4 it's easier. The RAW headroom data is automatically squeezed out, but from every image. Even those that barely have any. That waters down the resulting HDR, and all highlight details are mushed together. Here's how that looks like after merging and tonemapping:

Highslide JS

Both images merged with Photomatix and tonemapped with identical settings (Default preset, +8.0 Detail Contrast).

Long story short: These are the development settings for Lightroom 4 to get optimal HDR results.

These settings will make sure the highlights (that LR4 recovers anyway) are not compressed so tightly together. They basically iron out the shoulder kink of the tone curve. I tried it with a dozen different images, and these settings consistently result in 1.5 to 1.8 EVs more dynamic range in the HDR.

Go ahead and give it a try! Lightroom4 is a free download from Adobe Labs. Free until March 31 (but of course, you’ll be hooked by then).

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