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High Dynamic Range

June 25, 2007

It seems quaint now, but, back in my high school days, I learned photography the old fashioned way, with film cameras, darkrooms, and projectors.  At the time, digital photography was very much in its infancy, and the best cameras around still used 3.5" floppy disks to store their whopping 11 images.

My experience in the darkroom, however, taught me that actually taking an image is only one part of composing a truly great photograph.  Back in those days, post production was handled in a darkroom, with the projector and the various developing chemicals.  These days, it’s done on computer, with Adobe Photoshop or some other photo editing application.

But digital photo editing hasn’t just supplanted the darkroom, it has actually opened up the door to a whole slew of options that no projector could ever possibly handle.  Case in point – High Dynamic Range.

So what, exactly, is high dynamic range?

Basically, when you look out on any particular scene, your eyes adjust across a dynamic range of light.  Whatever point you focus on, your eyes adjust to bring it into the proper "exposure".  Thing is, cameras can’t match this dynamic range.  This is why you can take a picture, get a building in perfect lighting, and find that the sky is completely washed out.  Or, conversely, why the clouds look perfect, but the building looks dark and underexposed.

HDR imaging combines multiple exposures into a single image, the idea being to create something that more or less mirrors what the eye actually sees. 

I’ve been wanting to experiment with this technique for a long time, and, yesterday, I finally gave it a shot.

Here are the two images that I started with.  Nothing special, right?

House 2House 1

One more or less gets the house right.  The other, the sky.  But neither, by themselves, makes for a compelling image.

Click on through to see the final HDR that resulted from combining these two.


HDR Test

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6 Comments leave one →
  1. June 25, 2007 11:54 am

    That is incredible! I am just now getting “real” camera and have always been jealous of the terrific pictures that you, Dad and Tim have always shot. The Mac makes it so much easier to really work with photos and video (My PC did alot – but it was nothing compared to the mac). How did you merge the two photos and what program(s) did you use?

  2. June 25, 2007 2:50 pm

    I used a trial version of Photomatix Pro (http://www.celestron.com/c2/product.php?ProdID=203)to do the HDR merge and tone mapping. The initial HDR output is nasty – it’s the tone mapping that really turns it into something.

    Once I had it about where I wanted it, I saved it as a JPG and took it into Photoshop, did some tweaking of the curves, and that’s what I got out of it.

  3. Dad permalink
    June 25, 2007 6:39 pm

    Matt, awesome results. Question – how long did it take to do 1 image & could I
    do it without to much pain?
    Dad

  4. June 25, 2007 8:42 pm

    Dad (and JB and anyone else interested)…here’s a quick rundown of what you’ll need to do.

    1 – Find a subject, preferably one that’s not moving. Get a tripod.
    2 – Set the camera to bracket three frames, at the highest EV setting (2.0 on the D80).
    3 – Take three pictures.
    4 – Download Photomatix Pro demo (do a google search, you’ll find it).
    5 – HDR–>Generate will open a dialog box. Browse to your three shots, stick with the program’s default selections, and hit OK
    6 – You’ll now get a nasty-looking image. Go back to HDR on the top menubar and select Tone Mapping. Mix and match the values, experiment to see what they do, and when you’re happy, make sure the output is on 8-bit and hit okay.
    7 – Save image as a JPG. Edit further in Photoshop, iPhoto, etc as desired.

    It doesn’t take that long. I put together three more HDR shots this evening in the span of about half an hour, from first shot to being said and done.

  5. Tim permalink
    July 8, 2007 11:09 am

    Isn’t it possible to do it by only taking one shot?

    I was talking about this with a graphic designer the other day, by chance … and they talked about doing it by taking one shot, digitally over/underexposing versions, and then letting the computer work through the details.

    I may have gotten the details a little off .. but it made sense when she explained it through.

  6. July 9, 2007 9:26 am

    It is technically possible – and I’ve seen a few examples floating around on the internet – but every time I’d tried to do HDR by saving a RAW image into multiple exposure settings, it comes out screwy. It’s too time consuming to fiddle with as much as I’d like, but I think the problem may be Photoshop’s embedding the EXIF data into each file.

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