PROJECT: Highlight Clipping

Highlight Clipping basically boils down to exposure and is a bi-product of the linear way in which our camera’s sensor captures light.  This is exposure at it brightest, where tones not only become pure white, but also become featureless and past recovery within our post-processing procedures.  This issue is less apparent when shooting with film, as with its eye-sight-like behaviour, the brightest of highlights tend to shade more gently towards a more detailed white.

There may be some examples where clipping, also known as blown highlights, are okay such as when photographing reflections in water or direct light sources such as the sun, lamps, or candles, and in these circumstances clipping is probably unavoidable due to the subject matter, or the need to increase exposure levels for other areas within the image; such as can be seen in the sunset shot below:

With Clipped Highlights

With Clipped Highlights

Without Clipped Highlights

Without Clipped Highlights

But examples of where clipped highlights are not acceptable, and are easily avoided, like in the photo below, are due to incorrect exposure used at the time of shooting.

Example of Bad Highlight Clipping

Example of Bad Highlight Clipping

Freeman (2011 p.48) suggests that when shooting, we should pay particular attention to our histogram display and to any available warning displays for clipped highlights.  As we can see in the examples above, which have been taken from Adobe Bridge, but are also available in most modern digital cameras; when clipped highlights are present within our image a flashing red block appears, highlighting those areas where tone has been lost to brightness completely.

Highlight Clipping is mostly avoidable if we adopt an optimal exposure strategy within our photography, but there are shooting techniques that could be adopted to assist in eradicating this such as; exposing to the right (ETTR) of our histogram, this is where an image is exposed as far to the right of a histogram as possible, without clipping the highlights.  This method increases the number of recorded tones within our image, which in turn reduces the image noise, due to the image being lighter, but the disadvantages of this shooting technique is that it could take longer to get the shot due to the time it takes to check and possibly re-check the histogram, and as the image could need a higher ISO to brighten it, there could be a counter balance in the reduction of noise previously gained by lightening the image.

Adopting to slightly under-expose your image is another way of avoiding highlight clipping as by doing this safeguards against blown highlights and clipped colour channels and requires less light to entre the sensor, enabling the use of lower ISO’s.  Disadvantages include the increase in possible image noise, due to the production of a darker image, and fewer discrete tones are captured by the camera due to the lack of highlights.

So, as stated at the beginning of this post, Highlight Clipping basically boils down to incorrect exposure and it is up to us as photographers to adopt the exposure strategy that we are most comfortable with to avoid this bi-product of linear sensor capture.

Source:

Reference:

Freeman, M.  (2011) The Digital SLR Handbook.  Revised 3rd Edition.  East Sussex: The Ilex Press Limited.

 Bibliography:

Freeman, M.  (2011) The Digital SLR Handbook.  Revised 3rd Edition.  East Sussex: The Ilex Press Limited.

Freeman, M.  (2008) Mastering Digital Photography.  East Sussex: The Ilex Press Limited.

Cambridge in Colour.  (n.d.) Digital Exposure Techniques [Online Article].  Available at: <http://www.cambridgeincolour.com/tutorials/digital-exposure-techniques.htm&gt; [Accessed 29 April 2013].

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