As an actor or a model, you trade in your visual appeal. Your headshot is not just for identification, it is your calling card and the best way to make a first impression. 
Your headshot is a way to convey your personality at a glance. Yes, people make snap judgments based on appearance and you want that to work out in your favor. Even for experienced models, it helps to get effective direction from the photographer because you can’t see yourself while you’re posing 🙂
Very often in castings, the headshot photo will determine whether or not an actor/actress/model makes the first cut.
For new talent, it is especially important for the photographer to be able to guide and direct the model. Part of growth as a model is being able to learn from photographers and to get to a point where they know their “angles”. This makes it necessary for the photographer to actually have the knowledge to pass on. Otherwise, it is a case of the blind leading the blind. For more experienced models/actors, it is a lot easier but they still need some guidance, especially if the goal of the session is to achieve a particular look.
Other considerations are the photographer’s skill at lighting especially when in comes to being able to handle indoor and outdoor locations, to make use of natural and artificial lighting and to blend them when the occasion calls for it.
It is always advisable to take a good look at the photographer’s portfolio to get an understanding of their competence with lighting, checking how much work they have had published and if they have worked with agencies. If you are looking to get your portfolio built, you want someone who has a good sense of what agents/clients look for. A phone call or in-person meeting would be a very good idea. Get in touch with me at photo@pixyst.com if you need help with this.
Pixyst 