Stephen Frink - Eric, you normally shoot digital stills underwater with your Canon EOS1DsMKII in Seacam housing. What motivated you to try video for the shark encounters aboard Shear Water?

Eric Cheng - I've been thinking for some time now that I should develop a skill set in underwater videography. I've been on five shark expeditions aboard the Shear Water now, so I'm very familiar and comfortable with both the destination and subjects. It seemed like the perfect trip to shoot video for the first time.

SF - Have you shot much topside video before?

EC - Prior to this trip, I had done no underwater videography, but I am familiar with the equipment from sporadic topside use.

SF - What gear did you choose, and why?

EC - I chose to use a Sony HVR-Z1U HDV Camcorder, in a Light & Motion underwater housing. A lot of people use the Sony HDR-FX1, which fits in the same housing, but I wanted a camera with the additional features that the Z1U offers.

For a long time, I resisted HDV because of its relatively low bitrate (high compression), but it's become clear that the quality of the picture is amazing given its low price point compared to professional HD gear.

The Light & Motion housing is a beauty, offering near-perfect ergonomics and handling in the water. There was almost no learning curve--all the controls are right under your fingertips.

SF - I'm assuming that if you know what the controls are meant to do topside, using it underwater in the Light and Motion housing will be easy. It is a comfort to know it handles so well in the water, for with video proper balance and buoyancy translates to smoother shots.

Obviously, sharks are subject that easily translates to underwater, making this the perfect choice for the variety of sharks off West End, Grand Bahama. Have you migrated to video, or is this the kind of thing you will restrict to certain subject matter?

EC - Given my partial migration to video, I think that I will always be conflicted about whether to shoot stills or video. Even though this was my first trip shooting video, the response to the clips I've posted on the web has been amazing. The movement of large animals in shallow water (with light rays dancing around everywhere!) and animal interaction with divers is something that is much more difficult to capture with still photography. I'll probably aim to do some of both when it's feasible to bring both rigs to dive destinations.

SF - I guess price is kind of a "relative" thing, but I see the Sony HVR-Z1U with a street price of around $4000. Many "objects of desire" in this realm are kind of expensive. However, I see there is also a Sony A1U now available for under $2000, and no doubt Light and Motion has housings for it as well. How does this camera compare to single chip mini-DV, for example? A camera with its feature sets at the $2000 price point seems quite a bargain in the HD arena. Does it truly perform?

EC - Price is indeed relative. I was referring to the low price point of the Z1U when compared to prior HD offerings which are well into six-figures! I chose to use the Z1U underwater, which is quite a bit more expensive than the A1U is (at $4,300 street), but uses three large chips in contrast to the A1U's single chip. The sensors are different too (CCD for the Z1U and CMOS in the A1U). The general consensus on the web seems to be that the A1U is challenged in low light, and one of the reasons I chose the Z1U was that I want to be able to capture clean footage even when light starts to fail. I do have an A1U as well, which I will use topside when the Z1U is sealed up in its housing and unable to come out to play.

But even in less-than-ideal conditions, the A1U produces images that are so much better than any mini-DV offering that there is really no reason to compare the two!

SF - I know the Light and Motion housing is rugged and well built. How are the ergonomics for a first time user, being thrown in with the sharks (so to speak)?

EC - The ergonomics of the Light & Motion HD are fantastic. Even I only took a few minutes to familiarize myself with the housing before jumping in the water, before long I was shooting and manipulating the controls by feel only. It only took three dives to get the trim weights positioned properly; the housing and camera are now only very-slightly negative and easy to handle in the water.

It was only when I was hanging on a line in 3-knot current that I felt like the camera I was desperately trying to keep a hold of felt a bit foreign compared to the familiarity of my Seacam. :)

SF - Here's the wild card for me, and the reason I've never really shot much video ... Is all the editing a pain in the butt? I'm assuming that software has come a long way in the past few years, but is it a huge deal to turn the raw HD captures into manageable projects, either for TV or the web?

EC - Editing is a pain in the butt! I use a PC notebook running Windows XP, which is generally considered to be sub-par when it comes to editing video. People always tell me to get a Mac, but all new Mac notebooks run Intel chips, and Final Cut Pro (the preferred Mac software for editing) doesn't even run on them yet (at the time I'm writing this--but its release will no doubt be soon).

Despite the problems, I was able to capture, edit, render, and upload small video clips to my website--all from the comfort of the Shear Water (when we had wireless connections at the dock in West End, and by using my Blackberry as a modem when we were at immigration coming back from the Bahamas). My videos were online before I even left the boat! Acclaimed filmmaker and photographer Norbert Wu was here visiting me in Oakland yesterday, and he was blown away by the quality of some of the stuff I had posted (for such small files).

SF - OK ... For those of us (like me) who will never be able to really walk away from stills, how is the resolution from single frame grabs if you really need to use them for print?

EC - HDV cameras capture HD video at 1080i, which is supposed to be 1920x1080, a 2-megapixel image. But it isn't quite that simple. 1080i is interlaced video, which means that only every other horizontal line is captured in every frame. Even worse, HDV cheats and only records 1440x1080 pixels and uses 1.33:1 aspect ratio pixels, which means that some interpolation is necessary to achieve the 1920x1080 output resolution. Interpolation combined with interlacing produces single-frame grabs from HDV cameras that aren't as stunning as you might think they would be.

Another issue is that the standard shutter speed for video is 1/60 second. The motion blur that comes with a 1/60 second shutter speed actually helps to make motion in video seem smoother. With faster shutter speeds, the resulting video can have a strobing effect when played back. So, screen grabs will only be sharp if subjects aren't moving, or if the videographer selects a faster shutter speed.

But given all of these caveats, a screen grab from an HDV source will yield an excellent, sharp image for the web use, but only a fair 4x6" print. Still, impressive, considering that HDV cameras are going for under $1,700 these days!

I've put some jpgs of some quick, screen grabs online, so you can see for yourselves what the quality is of a screen grab from HDV source. Remember that these are interlaced screen grabs taken from video not optimized for screen grabs. Better screen grabs from video can be accomplished by pulling only one field (all odd or even lines) from a frame and interpolate the missing lines.

SF - Thanks, Eric. Sounds good, and we'll be looking for the video from those white sharks in Guadalupe in August!