Salt water/spray , constant banging up and down for hours at a time., continuous motion in the frame pushing the codec to the limit.
Considering my 1st HMC152 lasted only 3 mths shooting these conditions, I'd say it's pretty harsh for a camera with no internal weather seals or protection. I guess we have different perceptions of extreme.
This was originally posted in the HMC 150 Footage thread, mod must have moved it because it's a 152 PAL model ??