Hello, could someone clarify a concept I still don't get about lens correction profiles?
NOTE: I know there are several "custom" profiles available made by users, but for this discussion I'm focusing on the ones already included in Lightroom (assumingly made from Adobe).
So, It's my understanding that these profiles are made to correct for the various distortions of a lens. But how precise are these profiles? Do they take into account the actual focal length at which the picture was taken (I'm thinking about zoom lenses here)? Because the amount of vignetting and (type) of distortion could vary between 17 mm and 70 mm.
If they really apply corrections based on the actual focal lenght, how do they know the amount of correction needed? To put it in another way, do the tech guys just calibrate a few sample points (i.e. 17, 35 and 70 mm for a 17-70 mm lens) and let the software interpolate the settings for the intermediate points or do they actually calibrate every single point in the range (17 mm, 18 mm, 19 mm, and so on)?
Hopefully some knowledgeable Adobe expert can unveil this mistery.