A group of divers come face-to-face with a school of deadly sharks, risking death or serious injury if one of the predators decides to strike.The freedivers - Carlos Estrabeau, 28, and 29-year-old Ocean Ramsey - got up close and personal with a variety of species including a Caribbean reef, lemon, nurse and tiger sharks.These images were taken by photographer Raul Boesel Jr who admits that these encounters can be worryingly unpredictable.He pointed to theories that sharks can sense fear by detecting electrical impulses given off by a diver's accelerated heartbeat, but said it was the adrenaline rush that drew him into such dangerous environments.Mr Boesel Jr from Curitiba, Brazil, travelled to West End in the Bahamas to capture images of the giant sharks.The 29-year-old said: 'When I'm photographing sharks, I only have so much control of the space between myself and them.'You have no control over distance if they want to approach you. Sometimes, the shark can be just inches away from the lens.'The way I choose to photograph certain dives will depend on a variety of variables including wind, tide, water clarity, current, depth and the shark's behaviour.'The brave photographer admits feeling scared when the predators circled around him and his two friends.He added: 'People ask me "How are you not scared of the sharks?" Of course I'm scared - I'm well aware of their capabilities as predators.'The adrenaline you get keeps you sharp underwater. Some people rely on being very relaxed.'This slows their heart down to give them a longer dive and they also feel the sharks can sense the electrical impulses given off by the human body.'There are theories that an accelerated heart beat can induce different behaviours from certain sharks, maybe even putting you in danger.'I like having the adrenaline; it keeps me on my toes. The day I don't feel that rush, I'll probably stop diving with sharks.'The freedivers do not use any equipment to help them breathe underwater which allows them to hold their breath for a more natural dive.Mr Boesel Jr added: 'You feel all kinds of emotions when diving with these beautiful animals. They range from happiness, euphoria, anxiety and fear.'I try to box up all those emotions and hide them somewhere deep inside as you don't want the sharks to know what cards you're holding.'If you show fear, they associate fear with weakness and weakness with opportunity.'They are opportunistic animals by nature, so they will test you if they feel like you may be a source of food.'I believe using breath-hold diving as a technique to photograph them is the best way to show the animal in its most natural state.'(dailymail.co.uk)ANN.Az