While most code replacement usage appears to be for sports photography, I have found some other uses that work well for me.
In this example, I am using it to allow me to have an optional display of exposure compensation. In other words, it allows me to display "-0.7 EV" if I had set a 2/3-stop compensation, but doesn't display any EV info if compensation had been set to 0. Using the {comp} variable alone would result in "0 EV" in captions. However, using the {comp} variable along with code replacements I can have cleaner captions, only showing EV compensation when actually used.
The attached code replacement file has a list of all the various compensation values from -5.0 to +5.0 in half and third stop increments. This should work well for all situations I can think of, but if your camera can return other values, then they'll need to be added to the list. If you look at the file, you'll see that it's very simple to do so. Also, you'll note that I prefer to show the compensation in the form of "-0.7 EV", but this could be changed to suit your own needs as well.
However, it is worth noting the format of the first few entries of the file...
comp
comp0.0
comp+0.0
comp-0.0
Each of these entries, is followed by a tab and then a space character. This is the trick that provides for the "optional" display of exposure compensation.
To actually use these replacements in captions for slideshows, image galleries, contact sheets, etc. you need to include the following "pseudo variables"...
\comp{comp}\
\comp{fcmp}\
...which will insert the exposure or flash compensation, or a blank space if it is 0.
-Ian
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