full day rates tend to be discounted against 2x half day rates. Same as a ½ day rate is often discounted against the hourly rate. The basic premise is to encourage the client to book the longer time slots. Also when you do an hourly job or ½ day job, the setup times (which are effectively non-productive time) for the shoots take up a lot of that time and you have to build that cost in. As you increase the time purchased, the setup (non-productive) time become proportionally less, so you can discount your rates a bit.
As an example, if a client where to ask me to produce some product and pack shots of a single bottle, it might take me two hours by the time I've set everything up, got the lighting right and taken the photos. If they had 7 bottles to shoot in hourly shoots, then it'd cost them 7x 2hrs if they did it over a few shoots. Now, once setup, i can get through the shots for 7 bottles in far less time - it wouldn't take 14hrs! So, the opportunity cost to them of going to half a day and giving me seven bottles to do in a single session is worth it. They could still give me everything, ask for hourly and take a risk I can do everything in 2hrs, or it might take 4hrs or 14hrs

...
Hourly rates push the risk onto the client - if the allocated time isn't enough for the project, they have to cough up more. It's a risk for them, do they try and be cheap and take the risk of one or two hours, or do they pay the little bit extra for the ½ day and reduce the risk, and maybe even go the full hog and buy in the day and be totally safe? By buying the ½ day or day rate, the client can 'lock in' the cost for a project and feel bit more certainty against cost and time over-runs. At the same time, it's off benefit to you as a business to have ½ or full day as you can allocate your time with greater certainty, knowing you (should) have that funding coming through.
The key (and difficult bit) is to making your hourly, ½ day and full day rates work sensibly without giving too much away i.e. making them enticing and worthwhile for
both you
and your clients.
The reality of pricing is what your local markets will support... it's great talking about this rate and that... but if you're wildly different to others in your area and can't offer any USP over and above theirs, you won't get the jobs.
Degrees in this & that don't matter too much other than adding (slightly more) credibility for some customers. If you're talking about supplying photos and video, then it's more about your actual skills and ability than about what you have on paper.... your actual photo and video portfolios will be what will bring customers in over time, and your professionalism and ability to deliver is what will keep them coming back. A degree in marketing would certainly help tho' as they know what buttons to push to attract punters, and how to reel them in once they're got in touch.
I think that all that makes sense...

.... now time to go get some work done
