Olympus TG4

  • It Used To Be Not If, But When!

    Anything taken underwater that has an air-space within it will have a tendency to leak. This sad fact of life used to be never more true than with cameras. There was even the once ironically named Society of Nikonos Flooders! So the philosophy of underwater photography combined with the realism of the likelihood of a flood coined the advice, “It’s not if, it’s when.”

    So why does something that is designed to keep the water out, let the water in? Well, it’s all down to the fact that you need to access a submarine housing from time to time, whether it is to renew a battery or replace a memory card. The seal at the point of entry is usually effected by an O-ring that sits it a groove and abuts another surface when the unit is closed up. If the point of contact between the O-ring and these surfaces is not scrupulously clean and smooth, free of any foreign bodies like hair or grit, the seal will be broken and water at the pressure of depth will hose through the so-caused gap.

    The O-ring must be lightly greased. This does not help it seal but simply allows the O-ring to flex and move as the two surfaces are offered up to each other. Too much grease can in itself cause a leak. You should just put on enough to make it glisten.

    Passing a clean O-ring between your lips can help you detect if it has any grit or hair clinging to it and you might do this before you re-grease it. O-rings are often supplied with camera housings as spares but the original will never wear out. You would need to damage it with a sharp object for it to need replacing.

    So keeping the opposing surfaces smooth and clean and placing a clean lubricated O-ring between them should maintain a perfect seal – but bad things can still happen. Using the wrong type of grease can cause a leak. If you use silicone grease on a silicone O-ring, it can cause it to swell or start to dissolve. Use the right grease - an environmental silicone - even on neoprene O-rings.

    Don’t leave your rig in a fresh water rinse tank. Other divers may not be so careful about your precious kit and a careless collision with another object being rinsed could cause some catches to come undone.olympus_tg4_package_1

    Isn’t there a better way? Well, yes there is. If you want a compact camera, what about the Olympus TG4 in an Olympus housing? You will need to maintain the main O-ring of the housing in much of the same way as you would any other make of housing but the TG4 has a second line of defence in the event of an ingress of water into it. The Olympus TG4 is itself an amphibious camera and can be used down to 15 metres deep just as it is. Put it inside it’s housing and, should the housing be found to leak, you will only need to ascend to 15 metres deep and later, open the housing and rinse it in some fresh water and dry it, before you are ready to reinstall it in its housing, first having discerned what caused the leak in the first place.

     

    nauticam_na_g7xIf you go for a compact in a more elaborate housing, buy a Nauticam and spend the additional £191 on a vacuum leak-test kit. These vacuum leak test are available on bigger more expensive Nauticam housings for bigger and more expensive cameras and nobody in their right mind would eschew the chance to never suffer another leak again.

    The vacuum leak test as an integral part of a housing was first introduced by Hugyfot. These housings are available only for more expensive cameras but when they were first introduced many years ago, several owners suffered flooded cameras. The problem was that these housings are securely sealed and locked using bolts. These bolts were sometimes not fastened tightly enough and when the clamshell housing was pushed together by the intense pressure found at depth, the bolts could work loose. When the diver ascended to a lesser pressure, the two halves of the clamshell housing could become loose and a flood was the result. The Hugyfot vacuum leak-test was the answer to this problem (now included as standard equipment on all Hugyfot housings) and Nauticam has more-or-less adopted a similar system.hugyfot_canonmk3_front

    This is how it works: The camera is sealed inside the housing with a lightly lubricated O-ring to seal out water, as usual. A pressure sensor within the housing confirms it is working and a (red) LED signals that the air inside the housing is at the same pressure as outside.

    The air is then vacuumed out of the housing via a special one-way valve using the pump provided. The pressure sensor inside detects that the air pressure is suitably reduced and a green LED shows. Green is good.

    The user then waits to see if the green light remains or whether a red light will show instead. It is recommended to wait around 20 minutes. If no air has leaked in, no water will leak in. Depressurizing the interior of the housing has a secondary benefit. Outside air pressure pushes the two parts of a clamshell housing together so firmly that you need not do up any bolts or close catches (should you forget) and you literally cannot prize the two parts apart without letting air back into the housing via the valve provided.

    nauticam_5dsrSo this cured at one stroke, the problem of Hugyfot users not fastening the housing bolts sufficiently, as well as ensuring there was going to be no leak. Hugyfot cured this design/user defect at one stroke.

    Underwater photographers find that winking green light to be very comforting on a dive and never open the valve to let air into the housing until they are out of the water and done using the housing. Now it’s not not-if-but-when, it’s green ensures your costly camera will survive!

     

     

     

  • Close-Focus Wide-Angle

    A new buzz-word expression that has developed among underwater photographers is Close-focus Wide-angle or CFWA. What is it and how do you do it?

    Terrestrial photographers have been using wide-angle lenses for years and some caught on to the idea that by getting really close to your subject with a very wide-angle lens on your camera gave you  the steep perspective that added drama and put the viewer right in with the subject. Doyen of war photographers, Don McCullin was a great exponent of this technique. He used to say that you need to get close to the action, then closer still.

    Photographers often talk about the quality of the glass - their lenses. Underwater, the one aspect that tends to ruin the quality of our pictures is the poor quality of the water we are in. It's full of detritus and plankton. 30-metres of horizontal visibility is thought to be gin-clear whereas if that was all you had in air it would be considered a heavy mist at least. It's a great leveller and sometimes buying better quality cameras can be fraught with disappointment. We need better quality water first! So we use wide-angle lenses not often to get a wider shot but to allow us to get close to our subject without cropping out any part of it.

    Olympus TG4 with i-Das Fisheye lens Olympus TG4 housing with i-Das Fisheye lens attached.

    Whereas a fish-eye lens would be a strange choice for a terrestrial shot, underwater it can make complete sense, allowing you to get really close. The dome at the front makes a virtual image by the refraction of the light as it passes from water to the air inside the dome and it's this the camera focuses on. It used to be the province of only very expensive DSLR cameras in tailor-made housings but now you can get an i-Das fish-eye lens for many compact cameras and the route is open for CFWA pictures. Look at how the steep perspective of the close camera-to-subject position translates into much more interesting pictures! Here are some examples.

    Firstly I show you the final shot that was first published in many diving magazines throughout the world and later published in Shark Bytes after the background was simplified by computer retouching in Photoshop.

     

     

    A Great Hammerhead shark a few centimetres from the camera lens _FFF5723 _FFF5724 A Great hammerhead shark searching for prey (stingrays) hiding under the sand.

    With moving subjects, the trick is to hold your nerve and let the animal come to you. This Great hammerhead shark was searching for its natural prey, Southern stingrays, hiding under the sand in the Bahamas. The water was so shallow I was able to use natural light and shoot a series of pictures in quick succession.

    I didn't need to wait for any underwater flashgun to recycle and get ready for the next shot that can take one or two seconds, which is far too long a delay when recording fast moving subjects.

    The shark was maybe 6-metres-long from front to the tip of its tail and that length translates into an interesting perspective when the nearest part is only around 10-centimetres from the camera lens' dome.

    Naturally, you need to use a fast shutter-speed (I used 1/500 of a second) to freeze the movement, together with a small lens aperture, and I achieved this by increasing the ISO setting to get that. I simply adjusted the camera in advance to be sure the sand was correctly exposed, checking the result on the camera's LCD screen. I then shot a fast sequence of pictures as the animal passed.

    If you shoot in RAW mode, you can adjust the files at leisure later on a suitably equipped PC to get the exactly result you want.

    The i-Das fisheye lens will screw directly to the front of an Olympus  Tough TG4 camera's underwater housing or it will need an adapter ring to fit it to any housing that has a 67mm thread at the front of its port. It works best with the 28mm (equivalent) lens of the Sony RX100 Mk2 in its housing but you may need to zoom in to that equivalent setting with some later cameras such as the Sony RX100 Mk3 and Mk4. Come in to Ocean Leisure Cameras, the store within the store, and discuss your options with the experts. If you want to know more about the techniques of underwater photography, the Ocean Leisure book department has a wealth of resources and if you like the shark pictures you see here you can read about what it took to get such images, including plenty of pictures, in the new book Shark Bytes, also available from Ocean Leisure!

     

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