Friday 21 January 2011

DPP Exercise 9 - Scene Dynamic Range

At last a forecast of a sunny day albeit in the middle of the Country as opposed to where I live. Decided to visit a City I know well - Nottingham as I thought there was a fair chance of getting the conditions needed to do the Exercise.


This scene had a high dynamic range with the sky being very bright and the dark colours of the two figures in the bottom right hand of the image providing the deepest shadow area. The building on the left was in deep shadow although this was relieved by the light colouring of the stone. I estimate that the tonal range was approximately 10 stops. When transferred to the Camera RAW conversion software all the sky was shown as being clipped as was the dark clothing. Normally I would have taken an exposure for the sky and an exposure for the remainder of the image but for the purpose of these exercises I took a single shot and then used software to produce the final result.


This scene was 'flat'. It was in deep shade as the sun was behind the Castle rock and did not shine directly on the statue which is the focus of the image. Having transferred the image to the computer I found that there was less light and detail than I remembered presumably because of the ability of the human eye to adjust. I estimate the dynamic range as being less than two stops. The image shown is one that follows enhancement in Photoshop with the main effort put in to bringing out texture.


Another scene with a high dynamic range exceeding 8 stops. The sun is coming from the right and the small embankment with the trees on that side of the image was in deep shadow and was shown to be blocked out. The sky was bright by comparison and although not completely washed out had very little colour. The 'problem' was the building on the left where the middle section was brightly lit by direct sunlight and where the texture was not visible. It also had the effect of dominating the picture drawing the eye immediately to it. Opening the image in Camera RAW software I tackled the three main areas separately - I lightened the dark area on the left by about two stops; I darkened the bright part of the building by about 1.5 stops and then used a gradient to darken the sky.


A scene with an acceptable dynamic range with neither the highlights or the shadows being clipped. Some work has been done to improve the texture of the rock face above the Inn as this was in direct sunlight. Otherwise the image is as shot.


The challenge of this scene lay in the range between the brightness of the sky and the shadow of the canal basin and the adjacent building. Although there was clipping it was not as extensive as I anticipated when I took the shot. Again I tackled the desired changes separately and in the same way as described above,

I remain unclear about the purpose of this exercise. Although there is a need to recognise that a scene has bright highlights and deep shadows and that this will need to be taken into account in how the image is taken I do not see why the emphasis on numbers. I have spoken to a number of experienced photographers about their approach and I have yet to find anyone who thinks of the range in numbers relying instead on their experience and information provided by the camera's software to make decisions about the exposure(s) to use to capture the best possible image. The camera I use will show any clipped highlights and blocked shadows either by the 'blinkies' on the LCD or with the histogram. Whilst acknowledging that this information is not totally accurate it is a very good guide to what steps to take.






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