I thought I'd post an update to this older thread, since I recently made a little video when I was selling one of my sewing machines. I had just gotten an new iPhone 6 and wanted to try out close-up video shooting and editing capabilities of that phone.
You can see the video in all its 1080 HD glory here: https://www.youtube.com/watch?v=Dg12IXhcqkU
The video was filmed and edited entirely on my iPhone 6 using the built in software that comes with iOS 8. The superimposed text elements were added in the youtube annotation editor.
Other elements of this little production were seriously low-tech, though. I used scotch tape dispenser as a stand for my phone. I think it's important to lock in focus and exposure for these kinds of close-up shots, otherwise the exposure and focus will change constantly as you move in front of the camera. On my phone, you can touch the screen to lock focus on a specific area and adjust exposure for the duration of that particular video snippet.
I hope this helps.