High Dynamic Range

After stumbling upon a few breath-taking high dynamic range (I’ll call it HDR from now on) photos on flickr^â„¢, I’ve decided to make HDRs myself. Since I use a consumer-grade camera called Pentax Optio S55, where there is no in-built auto-bracketing feature (which helps you to take 3 photos of varying degree of exposure), creating one HDR image is not easy feat. So what I’ve used is a sturdy tripod, and the auto-timer feature of my camera. I took 7 photos, each 2 f-stops apart (2/3 EV spacing apart, in other words), from -2.0 to 2.0. By doing so you’ll get 7 photos that when combined, with give you a high dynamic range.

For dSLR users, if your camera allows you to save captured images in .TIFF or RAW format, do so to prevent excessive loss of data (since .JPEG uses a lossy compression algorithm) and to enable easier editing of images. Since my camera only saves images in .JPEG format, I’ve tweaked the settings so that the images are captured in the highest possible resolution and the highest JPEG quality – this necessitates the need of a tripod.

After transferring the images to your computer, you can use either Adobe Photoshop CS2′s automated HDR generator, or download Photomatix Pro, which is a dedicated HDR generator. Both programmes have their own strengths and weaknesses, but one point to note is that Photomatix Pro inserts a watermark in your HDRs if you use their tone-mapping feature.

HDR is said to nearly accurately represent what human eyes perceive the surrounding – the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows, as mentioned in Wikipedia. For example, in a landscape photo, the blue skies will not be white-washed but full of details, and the shadows in the valleys and vegetation will not be pitch-dark as well.

After all that talking, here are 2 HDRs I’ve created during my Penang trip, each of them merged from 7 differently exposed photos. They’re all clickable, larger images will appear in the lightbox :razz: have fun!

The photo above is the scenery taken behind my uncle’s house. Note the details of the sky and the shadowed grass under the trees .

Usually after generating the HDR (which will take quite some time, especially if you’re working with photos of huge resolution), tone-mapping will follow, and then you’ll be allowed to save the tone-mapped image on your harddrive after processing. I usually save them as 16-bit .TIFF files, because .TIFF does not use lossy compression techniques and every bit of details in the final HDR will be conserved (but that generates huge file sizes!) – this will make editing the HDR in photoshop way easier.

One point to note – since HDR images are usually saturated with colours, I usually tone them down in photoshop during post-production. The above two photos have their colour saturation slightly downtoned, but as you can see it’s quite obvious that HDR boosts the original saturation.

More HDR will follow, stay tuned!