Developer: eyeApps LLC
Price: $1.99 Download on the App Store
For the uninitiated, HDR photography is all the rage, supplanting tilt-shift photography as the trendiest way to manipulate your photos and earn your Flickr feed a little extra attention. Previously the domain of only high-end digital SLR cameras and pricey photo manipulation software, it has now come to the Apple iPhone, in the form of a handful of competing apps. Pro HDR is among the most popular of these and easily among the top iPhone photo apps, too.
So, what is HDR photography anyway? HDR stands for "High Dynamic Range." The "range" refers to the luminance of the photograph, specifically the difference between the lightest and the darkest parts of the picture. A typical photograph is at the mercy of the lighting conditions of the time and place at which it was taken. A skilled photographer might be able to reduce glare or squeeze a little more detail out of the shadows, but the result will rarely compare to the range of luminance recognized by the human eye. HDR photographs, on the other hand, more closely recreate the experience of being there.
The way HDR photography accomplishes this is a bit of cheat: HDR photographs are actually the combination of three exposures. Each exposure will capture a different level of detail, and then the exposures will be combined with an algorithm designed to retain the greatest degree of detail in each photograph. It is a complicated process, so any reader who wonders whether an iPhone app will be capable of pulling it off is justifiably skeptical. Pro HDR, however, will make short work of that skepticism.
Here is a great way to put Pro HDR to the test: using the default iPhone camera app, take a picture of a room filled with objects that are backlit by a window that is facing the camera. There are two possible ways this picture will turn out: either the objects will be clear and the window will be a square of undetailed white light, or the window and the objects beyond it will be clear, but everything in the room will be visible only in silhouette. Now try Pro HDR. You will see the room, the window, and what's beyond it. It actually works. For an app that costs only $1.99, this is a small miracle.
Pro HDR doesn't stop there, however. The app is packed with features. When first launched, Pro HDR will allow the user to choose between three modes: automatic, manual, and library mode. Automatic is sure to be the most popular. When this option is selected, the user may just point and shoot, and Pro HDR will take care of the rest. It will take three exposures, make adjustments, merge them, adjust them, and save the shiny new HDR photograph to the photo library. The user will also have the option to upload or e-mail the photograph. The manual option is essentially the same, except that the user may control the three exposures and the amount of detail captured. In library mode, the user may select previously-captured photographs, so that they can be processed into HDR photos.
Much has been made of the new, built-in HDR technology available to iPhone 4 owners running iOS version 4.1. Users who have tried both still seem to prefer Pro HDR, but if you own an iPhone 3GS or simply can't upgrade to 4.1 because it will disable your jailbreak, the choice is an easy one: Pro HDR is definitely worth the modest price.