Art Direction is an elastic term which causes a lot of confusion. Depending on the discipline, the term has different meanings.

Advertising, Web Design, Media
Art Direction has traditionally been defined as "translating an overall objective into a visual solution" which is simplistic but true. But there's a bit more to it than that with the advent of new media - creativity is great but without understanding usage across mediums and the limitations of each those fabulous concepts will never be fully realized.

In larger organizations Art Direction is subserviant to Creative Direction. Creative Direction entails interpreting a client's communications strategy and then developing proposed creative approaches and treatments that align with that strategy. Art Direction provides input to the creative process while bridging creative vision with the technical realities of production, ensuring and maintaining uniform output across varied mediums. Some things Art Direction would envelop are;

Graphic Design
Web Design
Illustration
Photography
Models
Collaberation with Copywriting
Stock image research and licensing
Creating and/or ensuring Compliance with style guides
Consistency with existing designs
Coordination with developers and QA
Print Management
Color Management
Coordination with audio/video production

Unless there is a necessity for separation of duties (i.e. project scope, client request) or we're hired exclusively for Art Direction under a Creative Director, G FACTOR performs both roles as a single entity.

Television and Film Production
Art Direction in TV and Film is predominantly an adminstrative task - assignment of tasks, budgeting, scheduling, liason to other departments - especially construction, and of course actual art/show element production & direction as the title implies - all to ensure fullfillment of the Production Designers vision. As with Advertising, a deep understanding of design and production processes makes Art Direction imperative to ensure a successful production.