Thursday September 21, 1944 collision with tanker British Harmony, then with freighter Voco ( 5090 tons) while at anchor, then with tanker Empire Garrick - no casualties
By well-lit, what I mean is situations that fall within the normal range of your camera's exposure program. This is a combination of ISO (film) speed, shutter speed, and aperture which will result in capturing a desired image. On land, such situations occur all day long, but underwater they are rare. Clear shallow water with a bright sun shining overhead is the only environment in which your camera is likely to work unaided, as it would topside.
An unremarkable ambient light test shot, at a depth of about 100 ft. Note the loss of colors, even close-up. Flash would bring out all the hidden colors.