Depth of field is important in photography because it adds drama to photos and draws attention to a subject. Typically this effect is achieved with good old fashion SLR cameras, but manufacturers have found a way to bring it over to mobile as well. You have your Nokia Refocus app, the HTC One (M8) Duo camera, and most recently Google's standalone Camera app, which comes equipped with a feature known as Lens Blur. They all promise the same thing, but which one is the best? We performed a few simple tests to find out.

In our tests, we obviously wanted to see how each performed under similar circumstances. We took three photos: one of Android figures staggered in a kind of rule-of-thirds setup, one of a closeup of a tree, and the last one of our Managing Editor, Roy Choi, disguised as our Editor-in-Chief, Sean Aune.

Nokia's Refocus and Google's Lens Blur are executed similarly by snapping multiple photos, and then taking that data to create the bokeh effect. If the right data is captured, users will have the ability to focus and re-focus a photo even after it has been taken. It's worth noting that Lens Blur is a tad bit trickier to execute because you have to press the shutter, and then raise the camera to acquire the desired data; that's not the case with Refocus, however.

The Duo camera in the HTC One, meanwhile, uses its second sensor to capture depth data, which is capable of analyzing distance and position of elements within a photo. That generates a depth map, giving users the Lytro-like ability to focus after the shot has been taken.

These are all just artificial replications of what can easily be achieved with an SLR camera—and not quite as smooth or convincing—but it's great to see more powerful experiences brought over into mobile cameras. The "shoot now, focus later" approach might not be something you'll use regularly, but it's definitely nice if you want to add a bit of drama to a photo, and really bring attention to your subject. Mobile photography has evolved at an incredible pace over the past few years, and this latest trend is a testament to just how far we've come.

Below we'll have galleries of each example arranged in the same way. So we'll have a regularly focused shot first, the foreground in focus second, and the background focused third. As you'll be able to tell, some of the experiences don't quite match up in certain shooting situations, or are much more subtle. With Refocus, for example, a shot needs to be setup in a particular way to achieve optimum results. When it works, however, it looks great.

What do you think of the results?

Google Camera Lens Blur, Studio

Nokia Refocus, Studio

HTC One, Studio

Google Camera Lens Blur, Android Figures

Nokia Refocus, Android Figures

HTC One, Android Figures

Google Camera Lens Blur, Tree

Nokia Refocus, Tree

HTC One, Tree

Google Camera Lens Blur, Sean Head

Nokia Refocus, Sean Head

HTC One, Sean Head

UPDATE: We are adding another gallery to provide a better example of what the Nokia Refocus app can do. You can actually play around with the photo here via this link. For whatever reason, Refocus was much more subtle in our other testing, and we're not sure why it couldn't handle the scene with the tree (at the very least). Maybe the community can shed more light on this. But to provide another example of the three different experiences, you can check out the additional gallery below.

Google Camera, Kindle and Toq

Nokia Refocus, Kindle and Toq

HTC One, Kindle and Toq