Monday, 5 July 2010

Saving the shadows and rescuing the highlights.

A couple of months ago, I was driving along a road, when I saw a castle through some bushes. I didn't have time to stop so I made a "way-point" reminder on my car's GPS device and carried on home.

Later, I bought my GPS upstairs and looked through the way-point reminders I'd made and saw that the castle was situated in a town called Zwingen (  47°26'15.48"N  7°31'37.16"E  ). Some 48 kilometers from where I live.

As it was a beautiful day, I decided to take a ride there to make some images for Google Earth. I enjoy doing the Google Earth stuff as it gives me an incentive to get out the house, explore the area and take some pics.

I got there shortly after midday which was a mistake as the sun was behind everything that I wanted to capture.

Normally (if doing this job commercially), I'd have come back later when the sun was in a better place. However, as this was just for fun, I decided to go ahead and document it anyway.

When I got home after the shoot, I was pleased with about 80% of the images but lots of them were suffering due to the high contrast range from the strong sunlight. This meant that there were either very strong shadows or burnt out highlights. Burnt out highlights are usually not saveable. For this reason, I tended to underexpose the images where I saw this happening on the monitor histogram of my 5d.

I ran the images where there were shadow details, through my HDR programme, HDR or High Dynamic Range photography lets you combine three successive images together so that the details in one of the images which you have purposely overexposed, is sandwiched over one which is underexposed. This means that the details in the highlights from the underexposed pic are visible as are the details in the shadows from the overexposed pic. All pictures should ideally be taken in quick succession and preferably on a tripod (to prevent ghosting).

Although I only took one image of each subject, I was able to use a special feature of my particular programme (Dynamic Photo-HDR.) whereby one image is processed as a "fake HDR". it's best to use RAW for this as there is plenty of detail for the programme to use. Perhaps the best example of its use can be seen on this image of a crucifix. Standing in the shade, it is hard to see any details in the shadows but the HDR process has done a magnificent job of bringing them out.

Untreated image from the camera compared with the HDR version

In the second two images, look how the process has bought out the details in the sky and especially in the leaves of the trees in front of the building.

There are plenty of HDR programmes available including freeware versions. I'm using Dynamic Photo-HDR  download a trial copy and see which works best for you.

See you later.

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