I think that we can expect every DSLR and compact camera that is launched from this point on to have video and stills capability. And this lots of people are going to want to shoot both on each dive.
One way to achieve this is to use filters and shoot video in ambient light and to either shoot stills the same way or with flash, using the white balance to overcome the effect of the filter (as Mike V showed in 2005).
But this is not suitable for many subjects, many lenses (macro) and many dives. And understandably, many people are going to want to light things up. Now strobes are no use for video, obviously. So many people are going to think about shooting stills with video lights.
It is perfectly possible to shoot stills with video lights, but there are several limitations compared to strobes. Afterall strobes were designed specifically for stills shooting (continuous underwater lights were available long before strobes were - but people still wanted strobes). The main problem is the continuous nature of the lighting, which means that shutter speed can no longer be used to independently control ambient light relative to foreground. They also prohibit long exposures - where the near instantaneous flash of strobe light will render a subject sharp. In my experience continuous lighting shots need to be at least 1/60th ideally 1/125th to be reliably sharp.
There are other issues too - and it would be good to see others contributing what they have learned. I know a lot of compact users have shots stills with their diving torch or video light. It would be good to hear from them.
Most underwater stills shooters are not experienced with shooting stills with continuous lighting. I know that I am not. So I thought it would be interesting to start a discussion thread on the pros and cons of the techniques. Please post examples if you have them.
Alex

