exacting

Making great demands; difficult to satisfy.

His exacting taste required no small degree of outward perfection.

[H]e burst into apologies which would have satisfied a more exacting man than I am.

Of an action, task, etc., requiring precise accuracy, great care, effort, or attention.

Wolf's work, which, though not very exacting, had to be done single-handed, kept him to his post.

Every photographer of experience has his own theories and methods of working, but for the last 14 years I have used a Leica exclusively, and have found it best adapted to the somewhat exacting demands of railway photography, which is by no means an easy branch of the art.

Of a person or organization, characterized by exaction.

"He is a hard, exacting, money-loving man," was my remark.