The people from the norwegian spearfishing shop Frivannsliv have measured the horizontal/vertical viewfield and the volume of several masks.
Frivannsliv - spesialist p fridykking og undervannsjakt
I thought it might be interesting:)
I apologize for not being a very active member otherwise..:nono: Anyhow I do have some interesting footage from my recent trip to Norway, I will sum it up and post it soon.
Safe and happy diving