A certain wildlife photographer puts up photos of bears online. To use those for any purpose you are supposed to ask for permission and most likely to pay for it. The question is, what if I copy the photo by drawing it (it'd be accurate, but looking obviously like a drawing, not a photo.) Can I use it for my purposes then? Or does it depend on how good of a drawing it'd be?
This is a derivative work and the right to make derivative works rests solely with the holder of the copyright in the photo.
If you make a drawing of the photo without permission then you must only use it in ways that meet the fair use doctrine if you are in the USA or the similar but more restrictive fair dealing doctrine in Commonwealth countries (do your own research if you are somewhere else).
Making the drawing to improve your skill and hang it on your wall is fair use - selling it commercially is not.
