Large video won't transfer from iPhone 4s to Mac

I have a 35 minute video in my iPhone 4s camera roll. It plays Ok on the iPhone but when the iPhone is connected to my MacBook Pro, neither iPhoto nor Image Capture can see it. Does anyone know why this might be and how I can transfer it?

Oddly, while trying to sort this problem out, I updated the iOS and somehow recovered three other shorter videos (one up to 18 mins long) that hadn't even shown up in my camera roll before. They transferred OK but the 35 minute one remains marooned on my iPhone.

Any clues?