ACR 4.1: Whats the difference between fill light and exposure?

Adding fill-light seems to do the same as bumping exposure so I am wondering what the difference is and when it is appropriate to use either ?

Fill light is supposed to increase just above the lower end (darks, shadows) of th ehistogram, while exposure increases the entire range of the histogram. When you use Fill light it seems like it affects the entire range because as you bump the lower range it moves into the upper range. But Exposure moves the entire range all at once.

Does that make any sense? It is really hard to explain.

It is like this.

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It's worth noting that exposure shifts the whole histogram to the right, and is used to set white point. Blacks is used to set the black point, and fill light just lifts darker tones, whilst leaving black and white points.

Thanks all.

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No problem, and if you want to get your hands on ACR 4.1 you need Photoshop CS3 - any EU buyers want a cheap upgrade? It's going cheap .
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