Pushing the Limits of Photography

I have been discussing HDR photography with friends and colleagues for the past few weeks, but it seems what everyone needs is a really good example. I have published a bunch of HDR photos on my Flickr page. But the real question is where do you really need this. Since discovering this technique, I find my self looking for shots where the dynamic range is beyond that which my camera can handle. I set up these shots just to see how it will look. This past weekend I succeeded in finding an example where HDR really makes a difference.

Below is a picture of a room and a window. Most photographers know that this shot is going to be difficult at best. The exposure either needs to be set for the room, or for the outside, but you never will get both. So I set up the camera, and took a normal shot. Here is how it came out:

Natural DR Shot

Please click on the photo to see the full sized result. What you clearly see is that the scene outside the window is considerably over-exposed. Note how the colors outside are almost completely lost as the brightness nears the maximum that the camera can record. At the same time, the room is dark, and again in the dark the colors the colors are similarly indistinguishable. This is using the camera’s on-board color conversion capability. Normally, I would use a flash with this kind of picture in order to bring the level of light to be nearer that of the outside. But a flash brings its own quality to a picture, drowning out the shadows, and making things look flat.

The camera actually can record more dynamic range than the JPG format can carry. JPG is limited to 8 bits per channel, and my camera records 10 bits per channel, which should be a factor of 4 more range. So I took a single RAW format picture of the scene, and converted it using the same post-processing that I did with the rest of these, only it is a single photograph. It certainly carries more dyniamic range, but the result is decidedly unsatisfying:

Single Exposure RAW

Then I took the picture again, with three different exposures, -2, 0, and +2ev. Here was my surprise. This is not enough for this scene. It is clearly better, but still the outside is a bit over exposed, and the interior colors of the couch are noisy. Three pictures was simply not enough. Here is what I got:

Three exposures RAW

OK. I am going to have to go set up again. This time I take 7 different exposures ranging from -6 to +6 in 2EV increments. Very dark to capture the colors outside, to very light to get the colors inside. The result of the combined picture looks like this:

The HDR version

Finally, that is a great shot. Please click on the photo to see the full scale photo. Of course there is a dramatic difference: you can see the colors of the garden outside the window, as well as the details within the room at the same time. This photo has tremendous dynamic range that could not be captured in a single photo. Go back and look at the original.

Isn’t this a dramatic difference? Anyone want to guess how long until camaras exist that will do this automatically?

2 thoughts on “Pushing the Limits of Photography

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