Tuesday, 23 November 2010

High Dynamic Range Photography - HDR

When we went to Brittany in June I took 487 images. This large number was mostly because I was doing multiple sequential images of rocky coastal scenes, for converting into panoramas later, but we were staying next to the sea looking westwards and so I also took several sunsets. With the idea of HDR at the back of my mind I did some bracketed shots as well. At least, I would have done if I had ever read the manual on my camera, so I set the camera to aperture priority and pointed it at the area which I wanted correctly exposed. I then held the setting while I recomposed the shot. The camera was handheld at a shutter speed of 1/60th second.
Later, after reading some articles in the photographic press, I wanted to try HDR digital technology for myself. The Amateur Photographer recommended Photomatix Pro, so I downloaded it here http://www.hdrsoft.com/download.html and then looked for some pictures to process. The Brittany seascapes looked promising. Here are the three images that I chose.

They are then loaded from within Photomatix Pro which aligns them, crops them and creates a 32bit image, for you to adjust if you want to, before moving on to tone mapping and creation of the actual output image. The three original images were jpegs with a file size of about 12Mb each. The tone mapped output file is a tiff of 33Mb. (I have reduced the images here to 540 pixels wide using Photoshop Elements, in order to avoid giving Blogger indigestion when I loaded them and so that they fitted better into my adjusted blog column width). You need a minimum of three images to give the correct exposure for the darkest, the lightest and the mid tone areas of the image. Some of the pros use seven exposures but that is not really necessary.

Having never used the software before, I was very impressed with the ease with which I could create a good result, starting from not very well planned images. (Much, much easier than using Mail Merge and Excel to create labels for Christmas cards, but that is another less interesting story). The illustrations here are very compressed and a lot of detail and sharpness has been lost compared to the original files.
The unreal quality, often associated with HDR tone compressed images, is definitely present, but with some adjustments that could be reduced.  It is also possible, using Photomatix Pro, to produce a result by exposure fusion, which leads to a more natural image, but it has less immediate impact when starting from these three original jpegs.
This looks like another package that I will have to buy!


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