i've had a couple jobs where the guy wanted me to show up for only 15 minutes because he needed someone on a camera and i felt bad saying it but i will not do anything for less than $100 a day.
WOW id consider you very generous. My rates are based on half or full day, 15 minutes is half day min, I wont go into exact details. Being in Japan as well I have a home or away rate. Home is Tokyo area, away is in another part of the country. Anyway this is drifting off topic.
To original poster. Seriously at the level your at I would factor it as $25 per hour to shoot and edit, plus expenses so around the $1k mark. As this is your first job though dont think oh well I reached my time limit job done, give them a quality project where you can. I think this is about commensurate with your experience.