Here are some images from two lakes in Austria shot with the Nikon D800E and Zeiss 21mm lens in a Seacam housing (no flash).
Fernsteinsee:
Fernsteinsee by Wild_Places, on Flickr
Fernsteinsee by Wild_Places, on Flickr
Fernsteinsee by Wild_Places, on Flickr
Quelltopf Fernsteinsee (this is the source point of the Fernsteinsee, diving is strictly fobidden there, but I was shooting from the edge without entering the water):
Quelltopf Fernsteinsee by Wild_Places, on Flickr
Quelltopf Fernsteinsee by Wild_Places, on Flickr
Quelltopf Fernsteinsee by Wild_Places, on Flickr
Samaranger See:
Samaranger See by Wild_Places, on Flickr
Samaranger See by Wild_Places, on Flickr
Samaranger See by Wild_Places, on Flickr