HDR or Manual Blending?
21st July 2011
Getting the full dynamic range in a high contrast image can be tricky and you can either resort to graduated filters, High Dynamic Range (HDR) software or manual blending. I knew I had to adopt one of these procedures for this image of Loudon Hill in Ayrshire as I would either have had a burnt out sky or an underexposed foreground.
Since filters offer a linear transition from light to dark the use of one in this case would have darkened the hillside as well as the sky, not an effect I wanted, so I was left with the other two options. Both HDR and manual blending require exposures for the highlights, mid-tones and shadows, so I took multiple exposures of the image, bracketing up to 3-stops either side of the metered readings. In this case the three-stops of underexposure was sufficient to capture the highlights in the sky. In order to make these exposures the camera needs to be tripod mounted and the frames taken quickly to avoid too much movement between exposures.
Back at home I had the option of photomatix HDR software or using photoshop to blend the images manually. Although manual blending is much more time consuming I feel the results are more attractive and controllable, so that is what I opted for here. I overlaid the 3-stops "underexposed" image over the image best exposed for the foreground and then used the erase tool to delete the underexposed foreground and reveal the underlying correctly exposed layer, whilst leaving the correctly exposed sky over the hillside. This is relatively simple and straightforward but requires patience along the horizon line, particularly where trees and foliage extend into the skyline. I think the image is an accurate reflection of what I saw at the time and I'm pleased with the result.
Note that there are some occasions where manual blending would be almost impossible, mainly where shadow and highlight areas overlap and interleave, such as sunlight through leaves. In these circumstances HDR software is just about the only way a full dynamic range can be achieved. Just be careful with the sliders - overcooked HDR images are a bit of a cliche these days and many are positively ugly in my view.
Since filters offer a linear transition from light to dark the use of one in this case would have darkened the hillside as well as the sky, not an effect I wanted, so I was left with the other two options. Both HDR and manual blending require exposures for the highlights, mid-tones and shadows, so I took multiple exposures of the image, bracketing up to 3-stops either side of the metered readings. In this case the three-stops of underexposure was sufficient to capture the highlights in the sky. In order to make these exposures the camera needs to be tripod mounted and the frames taken quickly to avoid too much movement between exposures.
Back at home I had the option of photomatix HDR software or using photoshop to blend the images manually. Although manual blending is much more time consuming I feel the results are more attractive and controllable, so that is what I opted for here. I overlaid the 3-stops "underexposed" image over the image best exposed for the foreground and then used the erase tool to delete the underexposed foreground and reveal the underlying correctly exposed layer, whilst leaving the correctly exposed sky over the hillside. This is relatively simple and straightforward but requires patience along the horizon line, particularly where trees and foliage extend into the skyline. I think the image is an accurate reflection of what I saw at the time and I'm pleased with the result.
Note that there are some occasions where manual blending would be almost impossible, mainly where shadow and highlight areas overlap and interleave, such as sunlight through leaves. In these circumstances HDR software is just about the only way a full dynamic range can be achieved. Just be careful with the sliders - overcooked HDR images are a bit of a cliche these days and many are positively ugly in my view.
