Barrie, three differences between the tg5 and tg870. TG5 shoots raw, TG870 only jpeg. Lens on TG870 has slightly more range. Big difference in price.
Here's what happened with me....My daughter and I were going on a shark diving trip. I had a tg4 and she had a gopro. The gopro died right before the trip, and gopro wouldn't help with a replacement since it was only a 4 black...So i scrambled and bought the TG870 a couple of days before we left. With the underwater presets the 870 performed well, and shot great videos as well. Since I wasn't doing much post processing to either camera's pictures, they both seemed really good to me. I also don't like housings..the one time I used one it failed, so now I just use the dedicated underwater cameras. Look at the reviews, whichever you choose, olympus makes the best dedicated underwater cameras. My daughter still wants a gopro for equestrian training work, so I am selling the 870 to fund it. So yes I am trying to sell my camera, but if you read up on the reviews, the 870 is very highly regarded, as long as you don't need raw. As I said above, I found the underwater preset to work really well so I didn't have to do much in post processing to get good jpeg images or videos out of it. Sorry for the long winded answer, hope this helps.
