AQUATICA AD7000 features (continued).

Hydrophone:

First, a little background info: All materials (air, water, wood, etc.) have an attribute known as “acoustic impedance”, which is proportional to that material’s density, and to the frequency of sound trying to travel through it. When sound is travelling between 2 materials, the more similar their impedances, the more easily sound is transmitted. Microphones present in DSLRs have an acoustic impedance close to that of air, so they perform at their best when used in it (on land?). When that same microphone tries to record sound in an aluminum underwater housing, the results are usually inferior. Metal has a much higher acoustic impedance (because it is much more dense) than air and water, so only a fraction of incoming sound pressure reaches the camera’s microphone after traveling through the walls of the housing. Hydrophones are specifically-designed microphones with acoustic impedances very close to that of water, so they’re (theoretically) able to record sound underwater much more accurately.

Now, onto Aquatica’s hydrophone.

Aquatica is the only DSLR housing manufacturer to provide a hydrophone as a housing option – let alone as a standard feature. Located just above the zoom knob on the top-left side of the housing, it is installed through an extra hole, which can also accept their remote triggers (or potentially an HDMI bulkhead for using an external video monitor…). The cable coming from the hydrophone has a stereo microphone jack (despite providing only mono audio recording) and connects to the camera through an access panel on its left side. Unfortunately, when the access panel is open, it interferes with the housing’s main o-ring, so extra care must be taken when closing the housing with the hydrophone connected.

Around Dominica, there are 2 main underwater acoustic attractions that I’m aware of – the communicating cetaceans that populate the waters, and a dive site called “Champagne”. The latter has dozens of streams of volcanic gas bubbles fizzing from the seafloor, sounding like an open can of carbonated pop.

Getting into the water with their resident sperm whales requires a costly permit from authorities, so that got moved from my to-do list to my bucket list. However, I was able to dive at Champagne a few times, so I did some hydrophone testing there.

Audio captured with and without the hydrophone is very different – but not in the way that I expected.

When the camera’s internal microphone is in a very quiet environment (i.e. an underwater housing), its sensitivity is, by default, automatically increased to bring out faint noises. Then, when the relative silence is interrupted by the crashing sounds of exhaled bubbles, the hiss from inhaling through a regulator, or the whirr of an autofocus motor, the camera cannot re-adjust the sensitivity rapidly enough to prevent a sharp spike in the volume. This creates very harsh sounds with a hard-edged feeling.

I didn’t realize until after the trip that the sensitivity of the microphone can be locked at one of three levels (low, medium, or high), but I suspect any one of them will not deal adequately with the range of underwater sounds typically encountered.

On the other hand, when the hydrophone is connected, the sensitivity level remains constant, and a broad range of underwater sounds is recorded without any abrupt spikes in volume. The sound of exhaled bubbles is reduced to a faint gurgle, inhalations become a whisper, and the autofocus motor becomes almost inaudible, but the crackling sounds of the reef can still be heard. It was even sensitive enough to pick up the hiss of my leaky first-stage. Although sound levels are much more balanced and smooth with the hydrophone, they are also slightly less intense.

The difference between the microphone and hydrophone is somewhat analogous to a pair of sensors having different dynamic ranges. At a given ISO (gain), one sensor might be able record brighter highlights (high frequency sounds) and darker shadows (low frequency sounds) in a single frame (unit of time) than the other sensor.

Aqua View Finder:

If you’ve never used an external viewfinder on your underwater camera housing, then you really don’t know what you’re missing. I used standard housing viewfinders for a dozen years before finally getting a taste of the good life in 2008 - and now I can’t (won’t) go back. Standard viewfinders don’t allow the entire frame to be seen at once, so it can be difficult getting precisely framed images. I often had to resort to what I call the “Ray Charles Technique” for framing with standard viewfinders – that is, moving my head side-to-side to piece together the full image in my mind. While external viewfinders are often viewed as a luxury item, they are regarded as a necessity by most serious underwater photographers. Who wants to spend thousands of dollars getting to a tropical (or sub-antarctic) destination, only to waste time and miss opportunities underwater?

The 8-element, black anodized and powder-coated Aqua View Finder eliminates guesswork when framing an image, providing a bright, clear view of the entire frame, even with your mask slightly away from it. Just like the camera’s eyepiece, you can fine-tune the dioptric strength of the Aqua View Finder using a special tool provided with the viewfinder kit. It doesn’t obstruct the rear LCD at all, so you can review images and access menus without restriction.

Standard mounting holes:

Shooting videos with a rock-steady camera is vital to producing professional-looking material. So, Aquatica included 3 threaded (1/4”-20) holes in the base of the AD7000 to allow the attachment of any standard tripod (or TLC’s new tripod, released at DEMA 2010). Tripods are useful for videos, but are also helpful for keeping the camera still enough to take long exposures underwater.

Missing controls:

There are 3 camera buttons that have been excluded from the AD7000.

First is the bracketing button, located just under the pop-up flash button. I can’t remember the last time I used this function on land, let alone underwater, so not having access to it didn’t bother me at all.

Second is the programmable function button (“Fn”). Its location on the camera (the nook between the camera grip and the lens mount) is likely what prevented this button from being incorporated in the housing design. There are already so many gears/levers/pulleys/springs/shafts in that corner of the housing, that I can’t imagine how another would’ve been included. I rarely use any of the functions that it can be programmed to operate, so I didn’t miss this one either.

Last is the preview button (“Pv”), which, by default, is used to check the depth of field of an image before taking a shot. Tucked underneath the lens, this button is in an equally awkward location, making a housing control difficult to incorporate. It can be programmed to operate all of the same function as the Fn button, so also belongs to the “unmissed” category.

CONCLUSION:

Boasting a new autofocus module, new metering system, new image processor, and new sensor (amongst other things), this consumer-level camera probably would have been regarded as a pro-level camera if it had a full frame sensor and a pro-style body. The recording of HD videos isn’t my cup of tea, but it seems like this capability could be a very productive when placed in skilled hands. The Nikon D7000 is easily the best DX format camera that I have ever used (but don’t tell my D300 I said that…).

With regard to the AD7000, there is only so much that 3D modeling programs can simulate and predict, so prototypes are never perfect. That’s why it is so important to thoroughly test a prototype before production begins, especially for an expensive piece of equipment like an underwater camera housing.

The design problems that I encountered with the prototype AD7000 were immediately addressed and rectified by Aquatica’s design team, which demonstrated the kind of dedication to quality that is essential for a company’s survival in this highly competitive industry. Of the few minor inconveniences that I mentioned, related to button placement, stiffness, and type, they were all based on my personal preferences, and were rather insignificant. Overall, I was very happy with the AD7000’s performance.

Including a moisture alarm and a hydrophone as standard housing features was a very generous gesture, which I’m sure users will appreciate. And if the multifunctional port-lock/lens-release is any indication of the capability of Aquatica’s engineering team, they have a bright and innovative future ahead of them.

ACKNOWLEDGEMENTS:

EQUIPMENT:

This review would not have been possible without Aquatica loaning me their AD7000 prototype. But they didn’t just box it up and ship it over to me… Aquatica’s president, Norma Alonzo, hand-delivered the package, and made sure that I had everything I needed. I communicated by phone and email with several other members of Aquatica’s staff, who were very helpful when troubleshooting in the field. These members include Blake Stoughton (co-owner), Joe Bendahan (marketing director), Luc Beauregard (engineer) and Jean Bruneau (technical advisor, who also loaned me some of his personal camera gear).

For more information about Aquatica gear, visit the Aquatica website

ACCOMMODATIONS:

Located in a quiet area just south of Dominica’s capital, Roseau, and minutes away from the popular Soufriere Scott’s Head Marine Reserve, Castle Comfort Lodge is a very homey oceanfront facility with only 14 rooms that, once again, made my stay with them a great pleasure (this was my 5th stay). Their comfortable air-conditioned rooms, dipping pool, seaside bar, and spectacular sunsets made off-gassing relaxing and enjoyable. Dining at their on-site restaurant was delightful, with delicious nightly specials served by friendly staff. I am grateful for their assistance with my lost luggage – they tracked and delivered them to me all the way from St. Lucia – as well as for finding and supplying me with tools that I required. My thanks go to all staff, especially Arienne Perryman (manager).

DIVING:

Operated from Castle Comfort Lodge’s dock, Dive Dominica is a very professional dive facility capable of efficiently servicing both small and large groups of divers. They have 3 dedicated dive boats ranging in maximum capacity from 10-24 divers, as well as 2 boats for whale watching and/or snorkeling trips. Dive briefings were consistent and thorough, and either 1 or 2 divemasters would accompany the divers, depending on the size of the group. Whenever possible (almost every day), dive staff went out of their way to accommodate my shooting needs – modeling for me, carrying my second camera rig, and letting me go as slowly as I needed. Doing 2 boat dives a day was enough to almost fill my memory cards, but if I still had space, or energy, I took full advantage of Castle Comfort’s great house reef. Tanks for these shore dives are complimentary.

Dominica’s reefs are some of the healthiest I’ve seen in the Caribbean – table-sized barrel sponges, colonies of long yellow tube sponges, and countless varieties of soft and hard corals blanket the walls, pinnacles, and slopes of the marine reserve. Fish life was abundant, currents were uncommon, visibility was great, and every dive left me wanting more.

Special thanks to Gus, Stinger, Reggie, Thomas, Brad, Odelle, Kevin, Imran, and especially Daniel Perryman (manager) for helping me with extra effort and patience.

For more information about Castle Comfort and Dive Dominica, visit: For more information, visit their website

GENERAL:

Another big thanks goes out to two of Dominica’s most well-known photographers - Simon Walsh and Arun “Izzy” Madisetti. They generously drove me around the island to photograph some of Dominica’s waterfalls when I wasn’t able to dive. Check out their website.

ABOUT THE AUTHOR:

Although only 26 years old, Keri has already accumulated close to 16 years of underwater photography experience. Educated as a mechanical engineer, he currently designs and develops products for ReefNet and is part of DivePhotoGuide.com’s editorial team. Over the years, his work has appeared in countless magazines, scientific journals, field guides, books, and museums, and he’s won over 70 awards in major international underwater photography competitions. For more of Keri’s work, see his website, or visit DivePhotoGuide.