Hydra 1.6

By: Erik Vlietinck - Last Updated: Sun 17 August 2008

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HDR is set to be the future of photography. Hydra is Creaceed's easy-to-use HDR application, but is it powerful enough for professional use?

HDR is the technique whereby you take three or more bracketed shots of a scene with a dynamic range that’s too high for any camera sensor to properly reveal the details in both the light and dark areas, and combine them in one image that shows all areas properly exposed. HDR reminds of the range of lightness values the human eye can bridge.

It’s also been said that HDR is the way of the future, because it can be used in a large number of applications. These range from photography for interior decorating magazines to panoramic stitching where some of the images that are used to create the panorama are much lighter than others.

A good HDR application will export to the OpenEXR format, which has been specially developed for HDR, has controls for compressing the High Dynamic Range data so it will fit into various output channel formats such as the web and printed copy, and enables you to simply combine the individual photographs using a blend method.

All of that is present in Hydra, but what makes this application special is the way in which the features have been implemented. For a start, Hydra exists as a stand-alone program as well as an Aperture 2.x plug-in. The plug-in was seriously updated in version 1.6, having gained a resizable window and the ability to re-import your HDR image in the Aperture library even if you save your image in OpenEXR format. Unfortunately, my Power Mac G5 wasn’t fast enough to have this process complete within a reasonable time, but Intel Macs shouldn’t have any problems with the plug-in’s performance (other Aperture plug-ins are also slow on my G5, so it’s definitely not a Hydra problem).

3D Interface showing LDR images and HDR image simultaneously

It can’t be resized and it should be bigger so you can see more detail. Luckily, the stand-alone version has a fully capable interface, with windows you can resize at will.

The stand-alone version shows you your Low Dynamic Range images in a column at left with the automatically created HDR image at right. The interface enables you to view the HDR image in two ways: upfront, flat, or in perspective with a nice mirror effect underneath. The regular view is good for detailed inspection, while the 3D view has its own appeal—some photographers will hate it, I’m sure.

Hydra has controls for merging the images correctly. The software uses a fully interactive technique for you to use when images don’t perfectly overlap. The technique is based on manipulating “nodes” that are automatically positioned by Hydra for best results. You can drag these nodes to different locations, add nodes, and then have the software re-calculate the images’ relative positioning until everything lines up perfectly.

Before you start tampering with the positioning, however, you should take a good look at your provisional HDR image that Hydra 1.5 automatically prepares for you: in 90% of the cases, the images are lined up either perfectly already, or as good as it will get. With HDR, the best still is to use a tripod so the camera doesn’t change position in-between shots, but if you don’t use a tripod and change the position inadvertently, you will soon see that you can’t improve on Hydra for lining them up properly—at least, I couldn’t.

Automatic results look good as they are

Generating the HDR is attempted fully automatically by Hydra 1.5 as well. Here I found you can improve on the software’s attempt quite a bit. That’s not criticism, because there’s one area where I couldn’t improve on Hydra’s automatic algorithm, and that’s when I tested the blending functionality. Although Hydra here offers a very cleverly designed control set to change the blending, the software is excellent at guessing the best blend of images to achieve a realistic effect.

If you do want to experiment, perhaps to create an absolutely over-the-edge effect, then you can by using Hydra’s histogram controls. In the Blend mode (called 8-bit in the Hydra interface), the histogram is shown with a vertical line representing each of your LDR images (each has its own label, like A, B, C, etc). Each line is positioned in a location on the histogram where Hydra “thinks” it will blend in the best. By dragging the line, you can alter the combined image’s looks.

In real-time you will see not only the image change, but also the histogram values. This gives you full control over the resulting image. The true HDR controls (32-bit image as a result) are less spectacular-looking, but just as effective and efficient. Two methods exist, of which one handles local adaptation.

These controls allowed me to fine-tune images with good results, and as Hydra 1.5 aims at making HDR output as easy as possible, I was perfectly happy with those results. However, I must add that Photomatix, which admittedly is more complicated to use—there are many more controls to get the HDR output just right—managed to get even better results. It’s not that Hydra’s HDR image wasn’t good, it is more that Photomatix’s result was excellent, and that it offered more granular control over the process.

Having said that, I truly believe that in 90% of the cases, Hydra 1.5 will suffice to churn out HDR images that look right. It’s only when you want to get the absolute best results, you’ll go for Photomatix and the steep learning curve that comes with it.