Handling Moving Subjects In HDR Images


Bombs Away - Underside of a B-1 bomber at Kingsville Naval Air Station

For the past several years I’ve taken my family to watch the Blue Angels perform in Corpus Christi. This year my family was out of town during the performance but nonetheless I made the trek to Kingsville Naval Air Station to watch them this year.  I carried two lenses:  a 70-200mm to capture some of the aerial performances and a 10-20mm wide angle which I used for 80% of the ground shots.

I took only a few pictures of the Blue Angels performance this year (I really like to *watch* and didn’t want to be overly distracted always trying to get the best shots).  However, I took plenty of shots of the static displays on the ground.  I bracketed many (shooting handheld) in hopes of generating some HDR images from the show.  On side note, I did try the panning IS mode on my 70-200mm lens and it did an amazing job capturing jets screaming past.

The image above was generated from three handheld exposures and shows the underside of a B-1 bomber with it’s bomb doors open — and a couple young girls doing some modeling.  It was quite a processing challenge (for my skill level anyway) due to the movement in the crowd.  In a night shot I’ve found masking in crowds to be far simpler because the darkness of the shot generally gives you a lot of leeway.  With a day shot like this I found it very difficult because when you mask in a moving subject from a particular exposure you often bring in bits of background (previously hidden by the moving subject in the tonemapped image) which severely differ from the tonemapped image.  Adding to my difficulty was the smoke in the background sky from the Tora, Tora, Tora performance.  As I worked to fix the background after masking this smoke created challenges in cloning in some sky…a great exercise for improving my skillset.

Here’s the rough outline of my processing on this image:  Tonemapping in Photomatix and lots of masking to get the people looking OK.  On a duplicate layer I played with exposure and contrast to adjust the sky to my general liking then I masked it in where I could — I wasn’t able to mask in everything around the people because of them being in a different position.  To get around this I used the clone stamp to add sky where needed (had to do this a bit on the ground as well).  I used Topaz Adjust to modify another duplicate layer and masked portions of that in.  Exposure/Levels/Curves followed that.  Finally, I tried a new sharpening flow which I picked up from @TipSquirrel today.  It involved using “Stamp Visible”, converting the new layer to a smart object, then using unsharp mask with that layer set to luminosity blending.  Probably unnecessary for this image but I wanted to learn something new.

I’m pretty happy with the image — my first handheld HDR (though it isn’t too hard to get decent exposures in broad daylight) and certainly the most challenge I’ve faced relative to the need to mask moving subjects.  Do you like it…?


6 responses

  1. Michael Currin

    Looks great. I might try some HDR with people and mask them in.

    Here is what I’ve done with Photomatix trial. It’s not as a amazing as some of the stuff I’ve seen, but I think my Waterfall looks pretty cool.

    March 30, 2010 at 11:56 am

    • I agree — the waterfall *is* cool.

      I tried using a single exposure but the background sky and flightline was so blown out that I couldn’t get anything back. The darker exposure brought in so much color noise that I decided not to mess with it. Who knows, it might have been less work in the end 🙂

      March 30, 2010 at 6:18 pm

  2. Michael Currin

    Here is an action photo I found on DeviantArt that was taken with one RAW file rather than a few.

    March 30, 2010 at 11:58 am

  3. Michael

    Trust me, after you do a few more images with moving people, you will find dealing with it second nature. At this point for me it isn’t even an issue, except that it’s one more step and takes some time. I usually find — whether it’s a night shot or a day shot — that I have to adjust the brightness of the source layer for the people to match the tonemapped image. Than, as you’ve already figured out, do the people first before adding any other edits or effects. In particular, I’ve noticed that adding effects, from Topaz or nik, etc, usually covers up any remaining evidence that the masked in people came from a different image than did the primary tonemapped image.
    The work here is seamless, and looks like it could have come from a single image.
    One last bit: I think you will find daytime handheld HDRs very handy. I even sometimes do so when I’ve got my tripod tight there with me, because I’m impatient. It means more time in post, but less time per shot in the field. The only downside I’ve found is 1-2% of the time the software won’t align them properly. Night time handhelds are another matter.

    April 3, 2010 at 2:50 pm

  4. I am amazed by some of the HDR portraits I’ve seen on DeviantArt. I’ve got a friend who’s going to model for me and I figure that if she sits really still I can use rapid shot and bracketing to get my 3 shots in half a second, to prevent blur.
    Otherwise I’ll do the RAW exposure trick.

    Do you reckon flash HDR would work? I mean like take a photo of a nature or city scene at night on a tripod, using 3 different flash power settings and aperture values instead of exposure.
    That would give a variety of dark to light shots but might be limited by the fact that a low flash setting will only get details of things up to a few metres away.

    Maybe combine with long exposures or slow synch?

    I’m busy for a few weeks, but let me know if you get the chance to try out the flash HDR or find examples online.

    I read that for tourist shots of large buildings and such, if you take enough shots you can mask out all the crowds to make the place look empty.

    If you did that with HDR you would get ghosting, but with 5 shots instead of 3 maybe they would disappear and you can paint over what remains with the 0 layer.

    April 4, 2010 at 7:08 am

  5. Michael Currin,
    I don’t know about the different flash settings, but it is generally a bad idea to change aperture settings in bracketed sets because it alters the depth of field so the images do not match up properly. Part of the scene will be in focus in some shots and out of focus in others.

    April 4, 2010 at 8:29 am

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