Now that iOS 4.1 is out for my iPhone 4, I loaded it up to try the feature I was most looking forward to: [HDR photos](http://www.apple.com/iphone/features/camera.html). HDR stands for [High Dynamic Range](http://en.wikipedia.org/wiki/High_dynamic_range_imaging), and is a way to get a photo where neither the shadowy areas or the bright areas are overexposed. It can also be used or “abused” to commit crimes against good taste. I’ve been using two iPhone HDR apps for a while, [Pro HDR](http://itunes.apple.com/us/app/pro-hdr/id347104281?mt=8) and [TrueHDR](http://itunes.apple.com/us/app/truehdr/id340741871?mt=8), and now that Apple’s thrown its hat in the ring, it’s time for a comparison.
Here are the examples, and below them, my thoughts. The following photo was taken in my driveway last night (sunsets are generally good fodder for HDR photos). The four shots are, in order:
1. The original “non HDR” photo that iOS 4.1 optionally saves when you take an HDR shot.
2. The Apple iOS 4.1 HDR photo
3. The Pro HDR photo, taken in “Auto HDR” mode
4. The TrueHDR photo, taken using “Take Pictures” mode.
All photos are unretouched, uploaded at full resolution (available on my Flickr – click to embiggen) directly from my iPhone 4.
###Original iPhone 4 Non-HDR Photo
* __The Good__: Fast, easy, and simple. Colors captured pretty well.
* __The Bad__: Shadows and dark areas underexposed. Could have touched the dark areas to get them exposed correctly, but then the sky would be overexposed and blown out. Hence the need for HDR.
* __The Verdict__: The iPhone 4 still has an amazing camera with great saturation and color. Unless you really need HDR to make a photo better, this is all you need.
###Apple iOS 4.1 HDR Photo
* __The Good__: Fast and subtle. Takes three exposures (instead of two, like Pro HDR and TrueHDR), and takes them near instantaneously (within two seconds or so). It’s still possible to get motion blur/ghosting, but it’s an order of magnitude faster than the other apps. Seems to go for realism rather than the over the top “ZOMG HDR!!1!” look. Free (if you have a device that can run iOS 4.1).
* __The Bad__: Subtle. May not give as much of that “HDR” effect you’re looking for. Colors aren’t as bright, and the image can appear a little washed out. Dark areas are still really dark (compare the grass and balloons on the left side).
* __The Verdict__: An great capability added to an already amazing camera. Will make a lot of photos better for almost no effort at all.
###Pro HDR Photo, “Auto HDR” Mode
* __The Good__: Auto Mode evaluates the scene, decides which bright and dark spots to expose for, then takes the two photos. Manual mode (where you pick the bright and dark spots) still available. Nice slides to adjust contrast, saturation, etc. available after the merge is complete. Does a better job handling the extremes of bright and dark than the iOS 4.1 HDR mode. Colors are bright and not too “unreal”. Only $1.99.
* __The Bad__: Even Auto mode isn’t fast enough for moving subjects. A “halo” is sometimes visible where two areas blend together (see where the trees meet the sky on the right). Sometimes the colors just _go wrong_. Merging the photos takes a few seconds (longer than iOS 4.1, but not as long as TrueHDR).
* __The Verdict__: If you’re a photography nerd like me, iOS 4.1’s HDR mode probably won’t be enough to scratch your itch. Pro HDR is a great tool for the virtual camera bag, and I recommend it without hesitation. If iOS 4.1 had never added HDR, I’d still recommend Pro HDR for taking cool HDR shots on your iPhone.
###TrueHDR Photo, “Take Pictures” Mode
* __The Good__: Often more subtle and realistic than Pro HDR (see the balloons and grass on the left side). Doesn’t exhibit the “halo” effect as much. Does what it says on the tin. A little birdie tells me that an “auto” mode might be coming in a future update. Only $1.99.
* __The Bad__: Slowest of the three to process/merge the two photos. No adjustment sliders for contrast, saturation, etc. Colors don’t “pop” as much as Pro HDR. Sometimes the colors just _go wrong_.
* __The Verdict__: Still a great HDR app, and future improvements could move it right into parity with Pro HDR.
What I’ve written is based on these four photos, plus the experience I’ve had using both Pro HDR and True HDR for a couple of months in various situations. The differences between those two apps are small, and sometimes performs better in one situation than another, with the opposite occurring under different conditions.
In the end, if you’re an iPhone photography geek like me, you’ll want to use the built in iOS 4.1 HDR function _and_ one of the third party apps. Which one to choose is a tough call, though. If it came down to it, I’d say get Pro HDR. But software updates can change the landscape quickly, and TrueHDR is a great app, too. You won’t go wrong with either of them.