I am Ubik...

iPhone 4 and HDR

One of the new features in the iPhone 4 is the ability to take high dynamic range, or HDR, photographs.  The way that this is achieved is by taking one normally exposed image, one over-exposed image, and one under-exposed image, then digitally blending the three together.  The ultimate goal is to give you detail in both the shadows and the highlights.  After all, film and digital photography has a relatively narrow dynamic range and it has to trade detail in one for the other.  By contrast, your eyes can capture details in the deepest shadows and brightest highlights without much effort.

I’ve been playing around with it for the last few weeks and I am mildly impressed.  For a cell phone camera it turns out a surprisingly good image.  Take the above images, for example.  I was shooting into a sunset on a partly cloudy, late summer evening.  The brighter image is how the iPhone’s camera would normally “see” the image.  The second has been processed using the HDR feature.  Notice how much more detail there is in the sky, how much more dramatic an image it was.  Given the conditions in which I was shooting the darker image is more like what my eye could (and did) see.

What it didn’t do so well is preserve shadow detail.  The HDR image lost some detail and darkened up the field and the stands more than is necessary.  It also introduced some strange motion artifacts around the moving players.

But after playing around with it for a bit in iPhoto I was able to get the results seen in the third image.  Here I boosted the exposure about 1/3 of a stop, then pulled the contrast back just a bit.  This lost me some detail in the sky, but kept the pitch (aka “soccer field”) about as bright as the original photograph.  Is it art?  Hardly, but it is a usable image that I can post to Facebook or Flickr without too much shame.  And it more accurately captures what the scene looked like than the normal image would have.

So while it is not a perfect imaging solution, the iPhone 4’s HDR capabilities do a pretty good job of producing quality images in tricky lighting situations.  While I wish the quality was better, it is a nice little tool to have in your meatball photography tool kit.