Fish-eye lenses

  • Photographing Sharks

    It’s easy to impress your non-diving friends and neighbours with the photographs you might take of sharks. Shark encounters come in a number of types: Chance encounters such as you might get ocean-roving oceanic white-tip sharks, encounters where currents attract requiem sharks that enjoy surfing on the flow, encounters with bottom feeding sharks such as nurse sharks and leopard sharks that like to lie up and rest during the day, and where sharks are feeding.

    The normal rules of underwater photography apply, in that it’s best to use a wide-angle lens and get as close as possible. Reduce the amount of water between your camera and the subject.

    Oceanic white tip shark Ocea-roving oceannic white tip shark

     

    Ocean roving sharks tend to be close to the surface so it’s quite possible to get reasonable pictures without an underwater strobe or flash but these are ambush predators so designed as to offer a low contrast image to intended prey. A correct flash exposure can give contrast and add drama.

    They tend to swim around 6m deep, constantly investigating anything that might be the source of a meal. That is why they approach divers, often only to turn away at the last moment when they consider us to be animals too big for them to take on. Sharks appear to judge size by height rather than length so if you want a shark to come close, present as small a frontal area as possible by being horizontal in the water. Go vertical and you will almost certainly scare off such a shark.

    Those sharks that lie about during the day such as nurse sharks can be approached with caution so as not to disturb them and you will have time to get more than one exposure adjusting the lighting and exposure to suit. The same can be said of white-tip reef sharks, although these are much more skittish. They lie about on the seabed during the day because they are able to force oxygenated water through their gills without forward motion like most other requiem sharks, but be aware that because they are grey and again designed for ambush, they need careful lighting just the same.

    Scalloped hammerheads at a cleaning station Scalloped hammerheads at a cleaning station

    Then there are the cleaning stations. Find out from the local dive guide which fish are the resident shark cleaners and find where they are aggregating. Then you just need to be patient, keeping as still as possible, waiting for the sharks to approach for a visit to the manicurist. It’s the only way to get pictures of scalloped hammerheads because they are so skittish. You need to sort out your overall exposure so that the background is reproduced an acceptable blue, adjusting the power of the flash (or strobe) to suit the foreground shark.

    When it comes to feeding sharks, things become a lot more frenetic. You need a fast shutter-speed but you will be limited to the fastest speed with which your camera will allow you to synchronise your flash.

    Sharks feed in two distinctly different ways. When chasing live prey they become very agitated and it’s best to keep clear at this time, even exiting the water. Sharks have more senses than we do but it’s a fact that they have a nictitating eyelid that covers their eyes to protect them at the moment of biting so that they virtually do the last part of an attack with their eyes closed. Mistakes can happen. Anyone who has attended a night dive at Manuelita Island near Cocos will attest to the fact, it can be chaotic, and that’s when it’s only little white tip reef sharks start hunting small fished by the light of the divers torches. Bigger sharks can explode with energy when they sense a live prey.

    White tip reef sharks competing for live prey at night. White tip reef sharks competing for live prey at night.

    On the other hand, when sharks sense there is a meal of carrion to be had, they are much more leisurely in their approach. There are no vibrations of injured or dying fish to excite them or ring their dinner bell, just the odour of an easy meal wafting on the ocean currents. So they tend to swim round in an orderly manner.

    Staged shark feeds such as they often do in the Bahamas and some parts of the Caribbean will give any diver witnessing the event that sharks, although impressive beasts, have a pecking order and act in an orderly manner so that they do not risk injuring each other. They still move quite quickly so you will still need to choose the fastest shutter-speed you can, in order to get sharp pictures. If you do not, the flash will record a sharp image but there will also be a less sharp ghost image due to the daylight exposure being too long.

    Using twin flashguns can also be counter-productive because those guys in the grey suits need a bit of contrast to light them up with plenty of shape and contour. It’s one occasion when the single flashgun reigns supreme.

    Caribbean reef shark at a staged shark feed. Caribbean reef shark at a staged shark feed.

    With plenty of sharks attending a staged feed, you won’t be able to judge where any are at a given moment. You’ll need to take a lot of pictures because inevitably one animal will obstruct your view of another, many times when you release your camera’s shutter. If you shoot RAW files, you’ll be able to adjust these after the event and not have to keep adjusting your flashgun’s output to account for sharks being at different distances from the camera.

     

     

     

  • Dome Ports for Underwater Cameras

    Serious underwater photographers shoot their wide-angle pictures from behind dome ports. What’s that all about?nauticam4.33domeport

    A dome port has no effect when viewing through it with the same medium (air) on both sides but once you put the outer surface in contact with water the refraction between that and the air in front of the camera lens comes into play. What happens is that a virtual image is formed ahead of the dome port and the camera lens is allowed to focus on that instead of the real subject some distance ahead. The effect is to produce an image that is more saturated in colour. The problem comes when you realise that this virtual image is curved and the distance in front of the lens is quite close.

    Some photographers get disappointed when they find that their expensive wide-angle lenses are no longer giving images that are sharp from side to side and resort to fitting them with high-strength dioptre close-up lenses in order to get them to focus close enough to get this virtual image sharp.

    That’s because most expensive wide-angle lenses are rectilinear designs that have a very flat field-of-view, something that is admirable when using them solely in the medium of air. At the same time, few focus close enough.

    That’s why you’ll see top underwater photographers using full-frame fish-eye lenses behind dome ports. Often these give very disappointing results in air but in conjunction with a dome port their aberrations actually become an advantage. A curved field-of-focus is a positive bonus where trying to make a sharp record of a curved virtual image.

    Dome ports come in different diameters with a different radius to their curve. The bigger the dome port the further in front of it the virtual image is formed and the easier it is to get the camera lens positioned at the right point behind it. That said, big dome ports can be unwieldy to use, hence the popularity of mini-domes. The smaller domes produce their virtual image much closer to the front of the port and it’s really important that the front node of the lens is positioned in the correct place relative to it.

    The front node is not something you can see. It’s an optical term. Camera housing manufacturers have done empirical tests with most popular lenses to confirm what spacer ring might be needed to allow the dome to be positioned in the right place relative to the camera. They provide lens/port charts for this purpose and your underwater photography equipment dealer will have that information if you cannot find it on-line.9inchzendome

    Dome ports can be made of acrylic material, polycarbonate or glass. Glass is the most expensive and the most hard wearing but if you are unlucky enough to scratch or chip it, there is nothing you can do apart from clone out the unwanted mark in your pictures, later with software on your computer.

    Polycarbonate is inexpensive and lightweight but the same applies as glass should you damage it. Acrylic ports have an advantage in that the material has the same refractive index as water so minor scratches become invisible in your shots underwater unless you happen to take a picture into the sun. Acrylic is very easily scratched but in the same way it is very easily polished.

    Simply take a piece of fine grade abrasive as used in finishing the paintwork of cars and gently cut back the scratch until they are has become an evenly matte surface. Then polish it back to clear acrylic using some proprietary silver polish wadding. It takes some elbow grease but you will be rewarded with a dome port that is immaculately clear of marks.

    Some say that glass ports are optically superior to acrylic ports. I have owned and used both including an optically coated glass port that I imported specially from Japan and can tell you that the pictures taken with both this and a top quality acrylic dome are indistinguishable.

    A manufacturer like AOI makes a range of glass and acrylic dome ports for Olympus system compact camera housings so the choice is yours.

    You may find that a large glass port is easier to use for those over-and-under shots taken at the surface because droplets of water are less likely to cling to the glass. A large dome port certainly helps get those type of pictures because, remember, the lens has to focus on a nearby virtual image for the under part and the over part is in air, probably at infinity. You need to use very small lens apertures to get the huge depth-of-field needed or a split close-up lens that affects only the bottom part of the lens. These rarely fit on fish-eye lenses.

    Some underwater photographers report good results using smaller domes for these over-and-under pictures but invariably they are in bright sunshine that allows them to use the smallest lens aperture with perfectly calm water, but they normally need to make an exposure adjustment in digital post-processing to get both halves of the picture in balance.

    The important thing to remember is that when buying a port, you will need the right extension ring to position it correctly relative to the lens. Alas, it’s not something you can confirm by taking a picture when in the equipment sales room and not underwater.977685_632320780114194_1262934048_o

  • How to Get Clear Sharp Pictures Underwater

    VerdeIsland5191There are some basic rules to getting clear sharp pictures, whether it be video or stills, while under water because it is the water that ruins so many good photographic opportunities. Firstly, the clearest water is not clear. Well, it's not as clear as clear air might be. If you could eliminate the water, think how much clearer your pictures would be!

    How do we do that? Simply by getting as close to your subject as possible and thereby eliminating as much water as you can between your camera's lens and your subject. That's why inexperienced underwater photographers have most success initially photographing macro subjects. Because they are small, it's easy to get the camera up close and personal to them. You only need to enable the camera to focus on them. Those with top-of-the-range DSLR cameras can equip themselves with a macro lens specifically designed to focus very closely. The lens merely needs to be installed behind a flat lens port or 'macro' port. Those with cameras that have a fixed lens (such as most compact cameras) will need to fit and auxiliary macro lens to the outside of their housing. The same can be said for GoPro POV cameras._DSC5564

    But what about bigger subjects? That's where a wide-angle lens comes into play. Again, a DSLR user will need to fit such a lens and mount it on the camera behind a suitable dome port. Dome ports produce a virtual image just ahead of the camera so you must be sure your choice of lens will focus close enough on that. The advantage is that a dome port keeps the angle-of-view the same for the lens as it would be if used in air. Wide-angle lenses are not used to 'get more in' but to allow the photographer to move closer without 'cutting more out'.

    Again, compact camera users will need to fit an auxiliary wide-angle lens to the outside of their housing. There is a variety of choices but you should be advised by an expert as to which will suit the fixed lens of your camera if it is not to vignette the photographs. The advantage of fitting lenses to the outside of the housing is that these wet lenses, whether macro or wide-angle, can be interchanged at will, whilst submerged.

    Water has another property that makes the life of an underwater photographer a little complex. It absorbs light so that as you go deeper it gets darker, but it also absorbs light selectively. The longer wavelengths of light (red and green) get soaked up first so that very soon, at a depth of no more than a few metres, everything will look blue in your pictures. What can you do about that?_DSC8326

    One way to look at it is to see it as a surplus of blue light and if you can reduce the amount of blue light you will allow the camera to make the most of the red and green light that still penetrates the water to the depth you are at. Some cameras allow you to "White balance" and provided the software designer has provided enough range to account for the excess of blue light, this can be very effective. It's best to point your camera at something neutrally grey to do this. A piece of white Perspex is ideal but failing that, the palm of your hand underwater can usually be good enough. Canon compacts are especially good at white-balancing against an excess of blue. Sadly for underwater photographers most software designers are thinking in terms of white-balancing against incandescent light, which tends to have an excess of red and green but those who work for Canon seem to have it nailed.

    Of course, some cameras do not have the facility to white balance, so what then? A red filter will make the most of what red light is present but of course you will need different degrees of red according to the depth you are at. You can fit alternate filters to a GoPro camera or you can fit a Backscatter Flip Filter 3.1 system. This gives you the option to flip the appropriately coloured filter in front of the lens and make a judgement by looking at the image on the LCD screen. If you have a Hero 4 Black or an earlier GoPro 3 you can fit an LCD back available as an accessory.

    A better way to get good colour in your pictures is to take some white light with you. In the case of video a constant light source is necessary and can vary in price from a basic Big Blue rig to something more ambitious. You cannot have too much light but it needs to be of the right colour and exceedingly even in its spread, or your video camera will try to look into the shadows and the lit areas will burn out. You will need a lot of light to get good still photographs even for macro subjects when the light source is very close indeed. Even a high-output Keldan light has a limited range. For good still pictures there is no substitute for an underwater strobe or even a pair of them. They emit a quick burst of light but it is many times brighter for that short duration than any constant light source. These can vary in price from the Sea & Sea YS-03 and Inon S2000 to the bigger hitters like the Sea & Sea YS-D2._FFF7119

    Professional underwater photographers shoot RAW files and there is a very good reason why they do this. RAW files allow you to do a lot of adjustments to your pictures after you have been under water when there might have been time constraints. Many compact cameras can shoot RAW files but because these files can be very large it can mean a significant delay of a few seconds between taking pictures. DSLR cameras have buffers of varying size that allow users to shoot a lot of RAW files without this annoyance. Depending on what you are photographing, the delay between shots might be worthwhile. Next week we'll show you the advantages of adjusting files from a RAW original long after the event.

  • Satisfied Customers Give Us Satisfaction Too!

    We received an email from Jakarta. It was from a family that had called in to Ocean Leisure Cameras while on their way to take their daughter to boarding school in Shrewsbury. It seems they don't have departments in Indonesian stores like Ocean Leisure Cameras so they wanted to get equipped with an underwater photography outfit to take home with them.

    Their message to us on returning home was that the results from the photography set-up we had suggested and supplied them with had exceeded their expectations in every way.  They were very happy indeed. In fact happy enough to write to us to tell us.

    So what did we sell them? The lady of the family wanted a camera that she could use in a fully automatic mode and was not going to be an imposition to carry on a dive with her. It appeared that cost was no object provided the camera and accessories would do what she wanted without her needing to develop much in the way of photography skills.

    The Canon G7X is a compact camera that employs a sensor that is among the biggest available in its class. This means it produces high quality files even when light levels are low and it can be set up for one button white-balance operation. An alternative might have been the Sony RX100.

    We combined this with a high quality Nauticam housing. nauticam_na_g7xThe lady and gentleman in question liked the idea of fitting a vacuum leak-test systemnauticam_vacuum_seal_check_system because it takes away the stress of wondering if the housing has been closed up properly and won't leak. The green light indicating this is very comforting.

    The lady expressed an interest in photographing whale sharks and we explained that the less water she had between the camera and her subject, the clearer her pictures would be. We supplied an i-Das UWL fish-eye lens that can be fitted directly to the front of the Nauticam housing via a 67mm adapter. This lens will allow her to get as close as possible and still include all of a whale shark in the picture. However we pointed out how the G7X needs to be used in conjunction with a short port and the zoom locked off by means of the lock on the Nauticam's zoom lever to stop it accidentally being zoomed forward. nauticam_n50_shortport2idas_uwl04

    At the same time, since they lived in Indonesia and were conveniently sited to visit its well-known macro dive sites where all manner of strange critters live, we suggested an AOI +12 dioptre macro lens. This too screws directly to the front of the housing.

    aoi_plus12_macrolens-1As for lighting, our suggestion that a Sea & Sea YS-D1 would be a good idea was met with the request to buy two since the gentleman of the family thought they would eventually progress to a double flash set up and getting an matching flashgun later in Jakarta might be virtually impossible. We were happy to oblige and provided a tray and arms with one-inch-ball mounting system.sea_sea_ysd1_a

    Of course this Indonesian family had an extensive budget but don't be put off by the cost. You could get equally satisfying results based on the economic Fuji XQ1 package fuji_XQ1_AOI_lensthat pairs the camera with a proprietary plastic housing, despite it being at an entry-level price. Be adding a lens mount base, this camera can be paired with the exact same auxiliary lenses and you don't need to have the top-of-the-range flashgun.

    If you want something in a price range between the two, what about the Olympus TG4? Its housing can too be combined with the lenses we mention (using a step-down adapter ring for the i-Das UWL fish-eye lens) and it confers the added advantage that the camera alone is water-tight to 15-metres deep so that takes a lot of pressure off the worry that you might not have closed up the housing correctly.olympus_TG4__fisheyelens

    However much or little your budget may be, we want you to go away with the equipment most suitable for your needs and that fits your budget. Come in to the store and discuss it with our knowledgable people. We take pleasure in making you pleased!

     

  • 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!

     

  • The Amazing Rhinopias

    _DSC8312 Rhinpoias Aphanes or Lacy Scorpionfish
    The Lacy Scorpion fish or Rhinopias Aphanes is found in the waters of Papua New Guinea and West Papua. Unlike a lot of colourful marine life, you don't need a macro set-up to get good pictures if you come across one because they can be up to 25cm in length. They are a benthic species in that they tend to rest on things rather than swim. However they often get about by hopping around on their pelvic and pectoral fins. Despite they fact that they appears to be very colourful in these photographs they are masters of disguise and although they often pose precociously atop sponges and coral heads, you can easily pass one by because under natural daylight they are quite hard to see. They were first brought to the attention of marine scientists by British/Australian diving pioneer Bob Halstead who after a career as a schoolmaster took to running scuba diving expeditions and later skippering his boat mv.Telita, taking divers on scuba diving charters around the waters of the Coral Sea, embarking his passengers at Port Moresby. Among other things, Bob Halstead has written several books on diving around PNG.
    Lacy Sorpionfish or Rhinopias Lacy Scorpionfish or Rhinopias Eschmeyeri
    After he started noticing these flamboyant fishes he sent some pictures that he'd taken to experts at the Natural History Museum in London who confirmed it was a previously undescribed species. In fact there are several sub-species. Bob is known for his insightful analysis of diving practises and also for his humour. One of his most well-remembered quotes is: "If you can't take a joke, don't take up underwater photography!" The first time I visited PNG I made it my business to photograph some examples of this keynote fish but after a lot of searching and no luck came back with an article for UK's Diver Magazine entitled 'The Rhinopias is Missing!' I kept my sense of humour. The next time I stayed at the Loloata, a resort on its own island in Bootless Bay run by Australian Dik Knight, the dive guides made it a matter of honour that they did not fail to find me an example to photograph. They took me to a reef called Dinah's Delight, named after Bob Halstead's first wife, also an accomplished scuba diver in her own right and it was if all the Rhinopias in various different sub-species had come out on parade. _DSC8421   To photograph these wonderful looking fish you need a a wide-angle lens so that you can get as close as possible and an underwater flashgun or strobe so that you can reveal them in their full spectrum of colour. The other things you will certainly ned is a pair of sharp eyes and a lot of patience whilst looking for them because in natural daylight they easily merge with their background.._DSC8406 One last point: Rhinopias are said to be the Holy Grail of marine aquarists who like nothing better than to keep one in an aquarium because these delicately coloured fishes are so pretty. Let's keep them in the ocean where they belong. (The pictures here were all taken with fish-eye lenses behind dome ports and with ancillary off-camera flashguns.)

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