Exposure Fusion: What is it? How does it Compare to HDR? How Do I Do It?
Today Mark Evans from Smash and Peas Photography Blog shares an explanation and starting points with Exposure Fusion.
Image by Seb Przd
‘Less is more’, or so the saying goes. But in this case, I guess its true; less effort and less time equals more productivity and and better results, what more could one ask for? So from where I’m standing, Exposure Fusion looks to have everything going for it, and then some.
What is Exposure Fusion?
Lets set things straight from the start, Exposure Fusion is not a kind of HDR.
Exposure Fusion is a fairly new concept that is the process of creating a low dynamic range (LDR) image from a series of bracketed exposures.
In short, EF takes the best bits from each image in the sequence and seamlessly combines them to create a final ‘Fused’ image. Or more technically, the fusing process assigns weights to the pixels of each image in the sequence according to luminosity, saturation and contrast, then depending on these weights includes or excludes them from the final image. And because Exposure Fusion relies on these qualities, no exif data is required, and indeed, if you wanted to, you could include an image with flash to bring darker areas to life.
Exposure Fusion Advantages over HDR
Using this process actually has a few advantages over HDR.
For one, no intermediate HDR image needs to be created, and therefore no tone mapping step is required either, making Exposure Fusion a far more efficient and quicker process. Not only that, but due to the algorithm used in Exposure Fusion, halos around objects that would otherwise ruin a nice HDR image have been completely eliminated, resulting in a more natural looking final image.
Exposure Fusion also has one other trick up its virtual sleeve. It can also create extended Depth Of Field images by fusing together a sequence of images with different DOFs. This could actually be quite handy, say if lighting conditions at the time don’t allow the full DOF to be captured in one shot, or if you’re just limited by the DOF of your lens. This process could also be used creatively to get different DOFs in one image.
Here are some examples of both methods – click to enlarge.
Exposure Fusion Software
At this stage Exposure Fusion is still in its infancy, so there’s only a handful of programs to choose from.
Enfuse is the primary tool for Exposure Fusion at the moment, and although it is a command line utility, there are ‘‘droplets’‘ (batch files) available that you can drag and drop a series of images onto to create a fused image.
Ingemar Bergmark has produced a GUI for it, not surprisingly called EnfuseGui, which can be a little easier if you aren’t too keen on command lines. If you’ve got Lightroom then one of the more convenient ways is to use the plugin. It still uses the command line utility in the background (you have to tell it where your enfuse.exe is), but the process looks more refined. However, the plugin is donation-ware so its limited to 500px final images until you donate to get the full version. There is currently no plugin for Photoshop. If you’re into photo stitching then PTgui and Hugin may be of interest to you. These programs utilise Exposure Fusion by stitching and fusing bracketed sequences together, with some pretty nice results.
Die-hard HDR fans may not be too impressed by this new revelation, but I certainly am. With no tweaking at all, a pretty reasonable final image is spat out of Enfuse. I must admit though, to get the images looking their best, a little ‘fill light’ in Lightroom helps, and adding contrast and saturation layers also helps bring out the best in the Fused images I created. I’d have to say though, it was a lot less arduous than endlessly changing settings in Photomatix to get things looking right, and I like the end result better, but I suppose on the flip side, this means less control and less creative input from the user, and on the odd occasion, you just can’t beat a nice HDR. Tough choice. I’ll let you decide.