The latest rage with digital photography is high dynamic range imaging. The problem faced by anyone holding a camera is that the dynamic range of their camera sensor is a fraction of that available to the human eye. Put simply, that gorgeous sunset and dark foreground you’re looking at simply cannot be captured with a single exposure from your camera.
This is where your Mac comes to the rescue with high dynamic range imaging, often referred to as HDR. Using HDR, you can take three shots of the same thing, one that is over exposed, one that is underexposed, and one that is just right. If you are really tricky and there is enough data in your image files, you can even make three copies of a single shot with different exposure levels. HDR software can then take these three images and combine them on your computer. This allows you to combine a gorgeous sunset with a foreground image. The results of this process vary from spectacular too surreal.
This week I’m taking a look at a software application designed specifically for the Mac to make HDR photography available to the masses. I’m talking about Hydra 1.6 from Creaceed Software.

Hydra is unique in that the $60 license gives you both a standalone application and an Aperture plug-in. Interestingly, the two iterations of this application are not identical. While I generally prefer to use the Aperture plug-in for its ease of use, there are a few additional tools in the stand-alone version of Hydra that I really like. Fortunately, the developer informs me that with the next major release of Hydra, the stand-alone tools will catch up with the Aperture plug-in.
One of the first steps of HDR image processing is to make sure the three pictures are aligned. In this regard, the Hydra developers did a very good job. The software or the user can pick specific alignment points and get everything straight. While generally you’re supposed to take HDR bracketed shots on a tripod, this feature allows Hyrda users to process images without assistance of a tripod. The software aligns the images for you. This could be quite handy when sun begins to rise and you realize you left the tripod in your car. My tests with this feature showed that it did actually worked and, generally, the automatic alignment did much better than my manual attempts.
Regardless, once your images are aligned, Hydra combines them into one image with all of the dynamic range data. This is where the fun really begins. The Hydra standalone application has a convenient histogram that allows you to blend the influence of your various images. While it’s not that easy to describe, it is very intuitive when you start doing it. The histogram is not in the Aperture plug-in yet but this is one of the tools the developer assures me will be in the next major update around the new year. Once your images are tweaked just right, you can export it to 8-Bit TIFF, JPEG, or 32-bit OpenEXR.
While the Aperture plug-in does not have the convenient histogram yet, it does have a variety of sliders and checkboxes to customize your HDR image. Because it is part of the plug-in architecture, all of this is done from within Aperture making the process of exporting images out for HDR and then dropping the finished product package back into your library quick and painless.
Creating an HDR images is much more an art than a science. Every picture is different and the tone map balance is never the same. For this reason, the real-time preview is a blessing. Also, like so many up-and-coming image applications on the Mac, Hydra takes advantage of your graphics card. The wait time to combine three RAW images on my MacBook Pro into an HDR image with Hydra’s Aperture plug-in was less than one minute. Obviously, your mileage may vary.
One problem I had was that Hydra stripped some of my metadata from its finished image. My lens information was gone and Hydra appended its name to my camera type. I understand the exposure information is probably no longer relevant but the lens information is very helpful and should remain. Again, the developers are already aware of this and a fix is in the works.
I think some comparison with the other popular HDR applicaiton, Photmatix, is appropriate. I own a license for Photomatix and have used it for some time. At $99, a Photomatix Pro license costs $40 more than Hydra. Having used them both I would say that Photomatix has Hydra beat with respect to the number of controls and adjustments. You can get very specific with the modifications to your image in Photomatix. With respect to the final product however, I couldn’t really tell much of a difference. This may be more a function of my lack of skill with Photomatix’s multiple controls but it also makes a point. If you are not looking for the most complex program but still want to make nice HDR images, Hydra may be in your sweet spot. Another point in Hydra’s favor is that it was created by a Mac developer and looks like it. It has a nice interface and doesn’t feel clunky like so many multiplatform applications. Fortunately, both Hydra and Photomatix have trial versions so you can give both a try and see which works best for you.
Hydra requires MacOS X running leopard 10.5.4 or later. While the developer says it can run on a Power Mac, they “highly recommend” you run it on an Intel Mac. Head over to their website and give it a try.
You can listen to this review on the MacReviewCast episode 172.