For a freelancer it is always difficult to quantify economically his work, especially if he works in the creative sphere.
There is, first of all, a discrepancy between “what should be” and “what is”.
In photography (but also for other creative professionals) my advice is to think more and to estimate, for each job, spending the time to reason well about costs and above compensation and to present and explain clearly to the client.
I personally I speak in terms of days (half a day costs 65% of a full day), course costs excluded, calculating always also the postproduction days.
Others prefer to calculate the hours.
The cost of a day varies greatly, according to various parameters, which I try to summarize below, but are subjective, my intention is to offer an example on which to build your method.
The type of service
It’s very different to take still-life images or being involved in an outdoor service, perhaps, tiring journeys by feet.
Counts, therefore, the location, but also the type of equipment required (and wear), the subjects, the interaction with them and, of course, your professional commitment and psycho-physical skills.
Obviously specialization and “fame” make higher rates.
A very important factor is also that of the buyer, which can be more or less demanding and present. Some devolved directly to the photographer around, others are very present, even on the set, which implies a subtle “ballet” between their desires and what you, as professionals, know to be truly effective.
It’s basically an accounting job, which can be done by your agent, but that implies, of course, additional effort.
Other professionals involved
Again, it is different working alone, or if other people are involved in a complex set, with a stylist, makeup artist, models, client and others. Such a situation is often complicated, from a practical point of view (perhaps the group is also multilingual), but also from a “diplomatic point of view”. If the situation and the budget will allow, is often welcome the presence of your agent on the set, which as a “filtering” function between you and others, so you can focus on your specific job.
Consider therefore always also the cost of your account/agent/agency (which I recommend you have) and assistant (other figure often indispensable).
There are then accessory costs, such as, for example, the time taken to request the occupation of public ground, in case of outdoor shooting, or the clearances for the photographed subjects. It’s a job that you can do (or rather your agent or assistant), but it must be quantified.
Please keep a percentage for any unforeseen situations. If you work outdoors, perhaps with a trip, it is customary, for example, calculate the “weather day”, the cost of the stop, in which you can not produce, but for you anyway imply a stop to other jobs. It should be done well understand the customer. Obviously, its cost is a little bit lower than that of the productive days.
The use of images
This is perhaps the most important factor and often the most difficult to make understand to the customer. It’s very different if you provide images (which always remain your property) for a website, for example, another if the client uses them for a book that will sell.
Two tips: never give in RAW files (attesting to your unique property) and always made clear in the budget that you will reserve yourself for later pictures’ uses.
Also in this case it comes to achieving a proper balance. It being understood, of course, that you can use them for promotional purposes (portfolio, your website, …), it comes to deciding whether, how and to whom you can sell them later.
If, for example, for a photo shooting for a tourist resort, should be no problem to publish a few months after some of the “advanced” shots in a magazine article, which would represent a form of promotion for the town itself.
Make clear it before, so as to avoid disputes.