water well in natural cave

A natural water well with dripping water in a limestone cave.­ The well was created by erosion from the underground water infiltrations.­

Spotted in this natural cave in Gunung Mulu National Park (Borneo)

Photo processed in True Tone HDR with Tone Mapping from a single RAW exposure.­

caving clearwater cave system gunung mulu national park natural cave spelunking turtle cave water well

Photos processed in True Tone HDR.­

Those are High Dynamic Range (HDR) photos processed to represent the scene as observed by the human eye, i.­e.­ without some of the surreal effects that can be obtained with "heavy" tone mapping of HDR images.­

See also related series: HDR Photography (High Dynamic Range).

I sometimes do HDR processing from a single RAW exposure, since my camera has about 6-stop dynamic range in RAW mode.­ This is the only possible way to do HDR when shooting a moving subject.­

For those wondering about the technical part, here is some information about my workflow for producing tone-mapped HDR images from a single RAW exposure:

- The RAW image is used to generate 3 images using exposure compensation with Photoshop using Adobe Camera Raw: -2EV, 0EV and +2EV.­ This allows to capture about the entire dynamic range stored in the RAW file.­ You could also use Lightroom to do that too, or any software than can process those RAW files.­ In my case, I need to first convert the RAW files into DNG format (using the standalone Adobe CameraRaw Converter) because the version of Camera Raw that I can use with my Photoshop is not compatible with the RAW format of my (recent) camera.­ But you don't need to go through the DNG step if you have the latest Adobe software.­

- The 3 images (-2EV, 0EV and +2EV) are then merged into one HDR image using Photomatix (you could also use Photoshop to do that).­ This is basically an automatic process with no parameters to adjust.­

- The HDR image is then processed with Tone Mapping to obtain a displayable image.­ I use Photomatix for the tone mapping.­ There are many knobs that can be adjusted, but in general, to get a True Tone realistic image, I use 25% to 50% intensity in the Tone Mapping dialog.­ I then save the resulting tone-mapped image in TIFF format.­

- If needed, I then correct Chromatic Aberrations using the free and automatic Photoshop plugin from Photoacute, which works very well most of the times.­

- I then use standard Photoshop layers to do the usual final adjustments (Level, Curve, Saturation, Color Balance).­

Photo taken in the Clearwater cave system, during the so-called "Clearwater Connection adventure caving tour" in Gunung Mulu National Park (Borneo).­

View the Clearwater Connection Cave Map and a map of the entire Clearwater cave system. Our guide that day was Roland Gau, and we were 4 visitors in the group.­

The Clearwater Connection circuit is about 8 Km long and 6 hours of walking, scrambling, crawling and squeezing.­ No rappelling or technical climbing is needed, but knotted ropes are used at numerous places to pass difficult obstacles.­ The tour enters by Wind Cave and exits by the Clearwater River Cave.­ This is one of the most interesting caving tour that can be done by park visitors in Mulu.­

The Clearwater System is believed to be the largest interconnected cave system in the world by volume and the 9th longest cave in the world at 189 Km (as of 2011).­ For more information, read www.­mulucaves.­org.

View my other photos of Gunung Mulu National Park.

Photos taken in Gunung Mulu National Park (Borneo).­

For more information about Gunung Mulu National Park, read en.­wikipedia.­org/­wiki/­Gunung_­Mulu_­National_­Park

Photos taken in the Malaysian states of Borneo island (Sarawak and Sabah).­