very good

very well done. I understood most of this, but still ended up learning something new and useful.

everyone serious about filming something should see this.

thanks, the relationship between depth of focus and depth of field now makes sense in mind. Can you explain though where the naming convention for lenses comes from? I understand that a low mm lens will have a wide angle and a high mm lens will have a telephoto angle, but what is this based on?

this is great it explains it so well

I need an Advil, becuase that gave me a headache. I'm new to photography and filming concepts, and that blew my mind. If all that can't be explained any simpler, then I'm in trouble! But I do appreciate the resource and that I'm able to watch it a few times until it (hopefully) clicks.

Nicely presented and very well explained. Other explanations tell you about the problems but this gives you the reasons.

awesome... much appreciated