The Art of Photography: Chapter 4: Light

Exercise 1

I've uploaded a few bracketed photos along with their final high dynamic range or HDR image to illustrate the difficulties cameras have with dynamic range. the HDR is courtesy of Photoshop as I'e lost my photomatix key.. I have to say Photoshop has come a long way in this regard . Somewhat more realistic and it gives you more 'useable' control over how to manipulate the image... less gaudiness, so to speak. For whatever reason HDR remains an emotive issue. However I do believe it has a place in photography and I suspect that over the coming years the debate will settle down and much like the debate over whether colour photographs could ever be considered art now seems a non sequitor, so too HDR will take it's place in photography as a legitimate processing tool in photo production.

The first photo is in the courtyard at the British Museum. this is a composite of 7 exposures (I took one photograph in RAW format and then created 7 DNG images in Photoshop ranging from -3EV to +3EV and combined the 7 images using the Automate function in Photoshop. technically not a bracketing exercise but with similar results. the resulting image has captured the full range of details but this shortcut method is not without pitfalls: because the images combined are artificially created by exploiting the EV tool in Adobe Camera Raw, digital noise can be problematic and this can be seen in the shadows of the windows in the central building. I suspect that if I had contained the process to a maximum of 3or 4 images closer in EV say -1, 0, 1 and 2EV the total difference in range between them would not have picked up on the noise but it is nevertheless a god example of what can be achieved by combining a number of image of different exposure values.

The next set of photographs were taken in Girona in the Cathedral. I used a tripod and took 3 separate photographs using my camera's bracketed exposure function. the images were then combined in Photoshop to produce the top image. You will see that despite the high ISO, digital noise is well contained and the final image produces a pleasing mixture of lights and darks across a broad range of light. looking at the actual photographs that were taken in situ none of the 3 could be said to provide an accurate reflection of the detail in subject matter. The photograph containing details in the shadows has blown highlights... this is easily seen the histogram where the graph is skewed to the right. the opposite can be said for photograph containing details in the highlights (the dark photograph). That photograph has virtually no detail in the shadows. but the highlights are well defined and not blown. The histogram for that photograph was skewed to the left showing a loss of details in the shadows. The photograph in the middle, whilst capturing a good range of detail, somehow feels flat and still suffers from clipped highlights- the same can not be said of the combined photograph though.. it really does feel like you are there, taking in all the details of the scene.