Wednesday, December 10, 2008

Autumn Bower

PHOTOGRAPHER'S DIARY: The shady place on the bright day is the photographer's nightmare. As shooting nightmares go, this is a pretty bad one, and I post it as much for technical issues as for any aesthetic qualities it may or may not have. I had timed my shoot to be in the orchard when the low sun lit up the red and yellow vines. Shooting from a distance as in yesterday's image could be handled with a single exposure. I didn't care if detail was lost in the dark boughs of the distant trees. It was their overall gawky form I needed.

In contrast, this close-up only works if we can see the leafy vines covering the shadowed side of the boughs. Standing there I saw those vines clearly. My photograph could not encompass that range. Setting the exposure to preserve the bright leaves left the shadowed area in black gunk. Fortunately, back in October, looking ahead to taking up HDR, I made a number of images in bracketed sets.

However, processing this set of images for HDR created new problems. There was a constant wind that vibrated leaves and branches of a certain length. When I processed my images for HDR the software was unable to resolve some of this movement. Along the left foreground especially, leaves that were frozen in the individual pre-HDR images appeared multiple times in the combined HDR. You can see a bit of this remaining about 1/8th of the way across the bottom from the left corner and in the far right corner.

Even more damaging was the way HDR processing spoiled a key detail of the shot. In very bright sections the original photos showed crisp veins in leaves rendered translucent by the bright sun. In the HDR version these details were smudged unacceptably.

HDR created a few less significant problems as well. In the right corner and in shadowed areas there is more noise than I expected. This is a result of not making a high enough exposure to get the darkest tones of the image into the mid-range tonalities. I've since read that it's advisable for the left third of the histogram to be blank in the highest exposure to get the dark tones well exposed.

To resolve the problems in the photo above, I found it was possible to combine an HDR and an ordinary image, making use of the parts of each that showed details best. Most of the image is a regular, unprocessed image. I chose one that handled bright areas well. The HDR version is the source of dark areas and good transitions to the lighter areas. Using an eraser with a soft, gradient edge I removed sections of the top, non-HDR image to expose the underlying HDR. The areas of the HDR exposed are along the shadowed areas and some sections where shadow and light mingle.

It's very easy to use HDR to stretch tonalities in very extreme and unnatural ways, and it can be useful for creating surreal or expressionistic distortions. My aim here, however, was only to open up the shadows and restore what was missing. I could have brightened the shadow considerably, but chose only small adjustments. Too much HDR and highs and lows are saturated but compressed. To me such images scream "HDR."