Photo Details: Giraffe (Giraffa camelopardalis) at full stretch, using its long tongue to pluck choice green leaves from upper branches, Kruger National Park, South Africa.
Camera: Canon EOS 450D (Canon Rebel XSi 12.2MP); Lens: Canon 70-200 F2.8L IS USM; Focal Length: 200mm; Shutter speed: 1/400; Aperture: f/8; ISO: 400; Exposure compensation: +2/3; Date: 28 Oct 2009, 8.49am.
Additional Info: The giraffe has a long, prehensile tongue (i.e. adapted for grasping, especially by wrapping around an object) that can be up to 45cm (18″) long. This, combined with a dextrous upper lip, allows the giraffe to manipulate the branches so it can get its tongue in between thorns or twigs and strip only the succulent leaves. In this way it can feed selectively while still consuming the quantity of foliage needed to sustain its massive bulk.
In the above image, the sky is totally washed out with no detail as I over-exposed by 2/3 of a stop. It was overcast yet reasonably bright, conditions in which the camera’s meter can easily be fooled when aiming up at a subject with plenty of sky in the background. In these circumstances, the meter can be unduly influenced by the bright area, expsosing for the sky and under-exposing the subject — so you end up with a nicely exposed sky and a giraffe in silhouette.
But I wanted the giraffe correctly exposed, showing detail in its face, and to achieve this I was happy to let the sky blow out. Although our eyes can adjust to see both the detail in the foreground subject and in the backround (or in the shadows and highlights), digital sensors (and film) don’t have sufficient latitude to show both correctly, so compromises have to be made.
Exposure compensation, where a degree of over-exposure is selected (the + side of the indicator), is usually necessary when aiming the camera upwards where there’s bright sky in the backgroud, as when photographing a giraffe’s head or, more commonly, a bird in the upper branches of a tree. In the same way, you may need to under-expose slightly ( – side of the indicator) if you want to make your subject darker, as when photographing a wet elephant.