Tue, 04. June 2013 – 10:02
Now that everybody is back from the trip to Turkey, the big run on the multimedia recorded has begone. Though Already having started uploading photos at the evening of the very first day, it was only this morning that I sent out an email to the rest of the S[&]T crew, pointing out the picture-set on Flickr. Only took a short while for the first first feedback with a question came in:
What kind of camera and/or lenses and filters did you use?
Some look sort of ‘surrealistic’, very cool!
As almost to be expected, the question was with respect to the HDR pictures published in the set, e.g. such as the one below of one of the archaeological sites in Side:
Since a) the question has been coming up multiple times and b) I think the reply actually is quite readable, here what I have been sending in as an explanation:
I guess you are referring to the HDR portion of the pictures. I am employing a technique called High Dynamic Range Photography (HDR), which aims at capturing a wider gamut of colors and brightness level as possible with a single exposure. Since the dynamic range of most scenes goes way beyond what the sensor inside the camera is capable of recording, the Ansatz is to essentially scan through dynamic range; this is done by taking a series of images of different exposures, centering the exposure measurement on subsequent intervals in brightness. In the case of most of my HDRs from the trip: I am taking 9 exposures in the range -4 EV to +4 EV (in steps of 1 EV), metering on the darkest to the brightest elements in the scene. Afterwards the frames are combined off-camera, yielding an image of dynamic range superior to the individual frames. What then comes into play is a process called “tone-mapping”: as the HDR has a dynamic range beyond the rendering capabilities of a computer display (and I guess even most printers), the HDR needs to be transformed back into a representation which indeed can be rendered. This step then typically is responsible for the surrealistic look, as there exists a multitude of mapping algorithms, each of them with several parameters that can be tuned to get the desired outcome.
For the capture I find that working with a wide-angle lens produces the most engaging compositions (i.e. framing of the scene) and final pictures: for almost of the HDRs I have been using a Tamron 10-24mm on a Nikon D300.
I am pretty sure that there are countless more detailed and more technical explanations out there, but if asked for a simple summary, the above comes pretty close to how I would try out the basic process.