How to take pictures like photography's underwater wizards

(CNN)Seems like everyone's a halfway decent photographer these days thanks to better gear, flashy phones and clever digital filters.

When it comes to underwater photography, though, few people have what it takes.
Perfect sub-aquatic images involve a new level of skills, like framing a shot while maintaining buoyancy and not getting eaten by predators.
    So where to start?
    We asked some of the planet's best underwater shooters for tips on the technique and equipment they use to make superlative marine photography.
    They shared their secrets and some of their best shots.

    Brian Skerry

    Patience is key to good underwater photos, says Brian Skerry.
    For the past 18 years Brian Skerry has traveled the world on assignment for National Geographic -- better known as every outdoor photographer's dream job.
    In three decades, he's racked up more than 10,000 hours down below, scuba diving under polar ice, dodging sharks and spending months on fishing boats.
    Spending so much time at sea has shaped his environmental awareness and he hopes his photos can help bring about change.
    "The oceans are in trouble," he says.
    CNN: What's the most significant change you've seen in underwater ecology during the past 30 years?
    Skerry: The depletion and degradation of marine ecosystems are among the most significant changes I've seen throughout my career.
    I couldn't have imagined when I began diving that the large schools of fish I regularly saw or the healthy coral reefs would now be nearly gone.
    The decline has been dramatic.
    Still, pockets of tremendous biodiversity remain and it's these places that I believe must be preserved.
    If you had to give one tip for capturing compelling images, what would it be?
    Patience.
    The best images of wildlife rarely happen quickly or soon after you arrive in a location.
    Watching and learning animal behavior and waiting for nice light is key.
    What camera setup would you recommend to the scuba diver just getting into underwater photography?
    If a beginner photographer can afford to put a DSLR inside an underwater housing, this is what I would recommend.
    This type of system will allow for tremendous flexibility and creativity and allow the photographer to grow.
    If the budget is tight, there are amphibious cameras available that can produce nice results as well.
    What's your favorite go-to photo gear?
    I've been a Nikon shooter since I started and their latest D5 camera is amazing.
    So good in low light and very responsive to every situation I've encountered so far.
    It has quickly become my go-to piece of gear.
    Have you ever been in a situation that was so dicey you asked yourself, "Why am I doing this?"
    I've had several.
    Being lost for a few moments beneath polar ice is one that immediately comes to mind.
    I was photographing a story about harp seals and diving in 28.5 F water (-2 C), where the ice was about 20 feet thick.
    The pack ice is always moving with wind and tide and during one dive I looked up to see the hole I entered through close.
    I found another way out, but for those moments while I was searching, I definitely wondered why I was doing this.
    But in reality, I've had a handful of dicey situations and countless magical experiences.
    The beautiful moments are what I most remember.
    See more of Skerry's work at www.brianskerry.com

    Adriana Basques

    Basques is known for her split-image photos, half above, half below water.
    Brazilian native Adriana Basques spent years as a business executive until a 1996 scuba diving course persuaded her to trade her briefcase for an underwater camera.
    Since then, she's traveled the world channeling her creative energy and using her art to speak to the importance of marine conservation.
    Today Adriana's work regularly appears in top nature magazines such as National Geographic, GEO and National Wildlife Federation.
    She's had exhibits in Smithsonian Museum of Natural History and her photography has been used in books and movie brochures and printed on swimwear.
    CNN: What's your favorite underwater destinations for guaranteed incredible photos?
    Basques: It all depends on what I'm looking for.
    Wildlife, especially big [animals], are never a guarantee.
    Although coral reefs are in decline, places like Fiji and Indonesia offer amazing reef scenery to build innovative images.
    If you had to give one tip for capturing compelling images, what would it be?
    First of all, be an excellent diver.
    What camera setup would you recommend for beginners?
    It's always easy to start with a point and shoot camera.
    They don't provide the complete array of features as contemporary state of the art SLRs, but do offer excellent features for certain applications.
    The learning curve can be much longer -- and spending a big budget on top-of-the-line photo gear without the knowledge of how to use it might be more wasteful -- until the skill level improves.
    However, if money is not an issue, purchasing the best camera gear and lighting system you can afford is a giant step in the right direction.
    What's your favorite go-to photo gear?
    I am known mostly for my split images.
    I love to give people that perspective of half-land, half-ocean.
    For that, I use a super-wide-angle lens (8-15 mm) in a full-frame camera with a large glass dome port.
    Lights are also key and for this setting I use two strobes with specially designed dome diffusers.
    For coral reefs, I add two more strobes for a total of four.
    What's the most significant conservation issue facing the oceans now?
    Climate change and ocean acidification are by far the most important.
    Overfishing, and pollution, like plastic and runoff from land, is strangling and killing the very source we rely upon for our survival as a species.
    Your photo, Big Mouth, is probably your best known. How did everything come together for that amazing shot?
    Knowing the behavior of an animal is always important.
    I needed something new to try since there are so many wonderful images of whale sharks.
    I anticipated the animal feeding on the surface and positioned myself in front of the mouth having the fishing platform behind me.
    Everything happened so fast and I only took a single shot.
    At first I thought I did not get the image correct because the shark was touching my dome port.
    Even with a super-wide lens it was too close to get the entire mouth.
    Breaking the rules can often lead to a more appealing image as turned out to be the case.
    See more of Basques's work at www.adrianabasques.com

    David Fleetham

    David Fleetham's advice: Picture the image you want. Get it.
    I met David Fleetham 25 years ago in Truk Lagoon on a diving expedition.
    We were exploring the World War II Japanese ships and submarines littered at the bottom of the sea floor.
    David was already a well-known and exceptional underwater photographer.
    That year, 1991, one of his shark images appeared on the cover of LIFE magazine.
    Since then, his photos have appeared on more than 200 magazine covers and in galleries in 50 countries.
    He's now one of the most published underwater photographers on the planet.
    A native of Canada, David moved to Maui in the 1980s and never left.
    CNN: What's the secret to getting on so many magazines covers?
    Fleetham: Determination.
    Back in the film days that meant sending out pages and pages of slides continually.
    Now it involves hours each and every day with my computer working in Adobe Lightroom, Photoshop and on my website, along with Instagram and Facebook, to get my images out all over the globe.
    Oh, and periodically I get to take my camera underwater and shoot new images somewhere in the world, or in my backyard, which continues to be a rather fascinating latitude.
    What's the hardest aspect of underwater photography?
    If you told a professional above-water photographer that you wanted to hire him to shoot, but you can't be sure what the subject really is or if the subject will be there, he must select his lens before he begins, carry all his camera and lighting equipment during the entire process and would only have an hour to shoot before he runs out of air -- this would be where you hear a "click" on your end of the conversation.
    If you had to give one tip for capturing compelling images, what would it be?
    Picture the image you want to get.
    Get it.
    Check everything on the display on the back of your camera to be sure and then continue with the same subject, changing angles, backgrounds, anything that you can think of.
    Use that unlimited number of exposures and then try what you don't think will work, or what someone told you would not work.
    You might surprise yourself and the rest of us.
    What camera setup would you recommend to the scuba diver just getting into underwater photography?
    I have shot with Canon SLRs for 40 years and continue to recommend them.
    I use Ikelite housings and strobes because they were the first company to really nail down the electronics to utilize TTL strobe exposures, which make a huge difference in many cases underwater.
    That said, I did a trip to shoot great white sharks off Guadalupe Island last year and the guy beside me in the cage got some great shots with a GoPro on a stick.
    Is there a place you've never been or an animal you've never shot that's still on your wish list?
    I have been to Africa, but just to photograph great white sharks.
    I would love to spend more time on the east coast and out into open ocean to experience the sardine run and all that goes along with that feeding frenzy.
    See more of Fleetham's work at www.davidfleetham.com