Rambler Photo Tips – HDRi

One of the main weaknesses of photographic images is that the normal camera will not capture as much detail as the human eye is capable of seeing. Another issue with images, especially those viewed on a computer monitor, or printed on an ink jet printer, is that the range of tonal values is extremely limited. Using a technique known as High Dynamic Range imaging, a photographer can create images that have a much wider dynamic range than is normally available. This post is a brief discussion of my experiences with this alternative method of producing images.

To be correct, even the methods I will be describing here do not result in a true HDR image. You might say that the result is a pseudo-HDR image. In fact, there are purists out there who are vehement in their objections to calling what I’m about to describe as HDR. I’m not a purist, so you’ll just have to bear with me and understand that I will be describing HDR as I understand the image type.

The Original Image

"Correct" Exposure

The image above was captured in the early hours around daybreak during a recent visit to Isle of Palms, South Carolina. The “correct” exposure setting for the light conditions that were present when I snapped the shutter were used. By itself, this is a very pleasing scene of a marina at sunrise. But the colors are somewhat muted and there isn’t a lot of detail available in the image.

The HDR Image

HDR Image

The next image is the result of combining three separate exposures, tone mapping, and then processing the image to create the JPG file you see above. As you can see, there is a lot more detail in the picture, the colors are more vibrant, and the sky is very dramatic. The reason for the difference is the high range of tonal values that are present in the final product. In my opinion, it is just a more interesting image.

The Process

Creating a HDR image:

1. First, and most important, use a tripod to capture the multiple images to be used in the final product. Because the images are combined, it is important that the camera catches the same scene each time you click the shutter. The best way to do that is with a tripod, or with the camera resting on a stable base. If you have a cable release, or remote shutter release, it helps to use that as well.
2. Refering to your camera owner’s manual as a reference, change camera settings to set the camera for Automatic Exposure Bracketing (AEB), if that functionality exists. If you don’t have a setting for AEB, don’t panic because you can still manually change the exposure between shots. You will also need to find if setting AEB automatically sets your camera to take multiple exposures, or if that is a separate setting. In most cameras, AEB will tell your camera to take three exposures with a range of exposure settings that are in 1/3 step increments, up to +/- two stops. I usually set the range at the maximum which results in one image at the “correct” exposure, one that is two stops over-exposed, and one that is two stops under-exposed. (See examples below.)
3. If not done when you chose AEB, set your camera to take multiple exposures, which will allow you to capture the three images as described above.
4. If your camera does not have a setting for AEB, or a setting for multiple exposures, you can still create your three images by taking the multiple shots at different exposures. You just need to be able to manually adjust the exposure setting. Also, be very careful that you don’t move the camera while you are changing the settings and clicking the shutter.
5. Download the images and process them using the HDR imaging software of your choice. There are several good applications out there for creating HDR images, and my favorite is Dynamic-Photo HDR, by MediaChance. Currently at version 4.4, Dynamic-Photo HDR is an easy to use, versatile program that does a nice job creating HDR images. There are several built in features that are missing from some software packages, such as a post-processing image editor that has a nice feature set and is able to use Photoshop plug-ins. In fact, Photoshop itself has an automated tool for combining and tone-mapping images to create HDR.

Exposure Examples

Examples of +/- 2 EV Exposure Range

Final Thoughts

That’s all there is too it. The process is not all that complicated, and pretty much any photographer with basic skills can use this method to create some pretty spectacular images. Dynamic-Photo HDR also has the ability to create HDR-like images from a single exposure. The process works best with RAW images, but can also use JPG files to tone map and create interesting results. My advice is to download the free trial of whatever software you may be interested in, play around, and decide if this is a photographic technique that you might find interesting.

The bottom line here is to have fun. I always try to plan my images to share something I have seen in a way that others are able to share the experience the way I did. HDRi is simply another tool in the arsenal to let others experience my world. Even if you decide not to explore this particular area of photography, I hope you still get out there and capture the world in your camera and give others a chance to see through your eyes.

Dynamic-Photo HDR Screenshot

Dynamic-Photo HDR

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