Recording a maths tutorial video with iPhone I am making a series of maths video tutorials to put up on YouTube.

I have made a wooden crane that positions the iPhone above my desk looking down so that it captures an A4 sheet of paper. (I have an iPhone5s by the way).

The quality is variable however. Some videos come out reasonably crisp, others blurry.

Crisp-ish:


Blurry:


Is there anything I can do to the iPhone to improve the quality?

I am working in front of a window, so I am getting ambient daylight (I don't really want to use a lamp because that will give sharp shadows of my hand).  I tried outdoors but then the recording is vulnerable to wind-noise.

If I touch the centre of the screen after the record button it sets the focus. I'm not sure whether subsequently moving my hand over the paper forces some refocusing. On my android device I could force manual focus.
Use the AE/AF Lock. Tap and hold on the place you wish to focus on. That should stop the camera from refocusing when your hand moves.