An introduction to digital photography underwater

by Steve Warren

The last three years has witnessed nothing short of a revolution in entry level underwater photography. The arrival of low cost digital cameras and housings has made quality underwater imaging available to almost all divers. For the first time budget underwater camera systems are available that are versatile enough to tackle subjects that used to be the exclusive domain of professional SLR cameras. As with any aspect of photographic equipment, a certain amount of care is needed to ensure that you get the equipment you really need. This section of our web site is designed to guide you through getting started on your research into choosing your first underwater digital camera. It is really not meant to be anything more than an introduction. Once you've had a look through this information we would invite you to call us with your questions or, better yet, drop by our showroom and talk through your needs with one of the underwater photographers on the Ocean Optics team.

Key benefits of digital cameras are

Real Image Viewing

The LCD monitor on the camera back lets you see your subject exactly as it will be framed on your photograph. This does away with one of the biggest disadvantages associated with entry level film cameras : the separate viewfinder. Separate viewfinders see, as the term suggests, a separate image to the lens. Overcoming this to get accurately framed images requires practice. Often heads or tails are cut off, or part of the picture is excluded or stuff you didn't want in the shot strays in. The LCD monitor avoids these problems altogether.

Instant Playback

The LCD monitor also lets you see the picture you have just taken seconds after you took it. This instant feedback lets you confirm that you got the picture first time or spurs you on to try again. The instant playback also puts you on a fast track learning curve. You will quickly discover what works and what doesn't. You can see the effect instantly in the water. With film cameras it is often hard to get your results processed on site. The delay in finding out how your pictures are turning out tends to hold peoples learning curve back. For many divers who will only get to use their cameras abroad a couple of times a year, this is a very real disadvantage to film.

Versatile Lenses

Digital cameras usually have zoom lenses built in. The zoom affords you the flexibility to frame shots the way you want and to zoom in on shy subjects. Keeping your distance from easily spooked critters makes it much easier to capture them on card. The close up or macro facility that is also built into most digital cameras allows you to shoot very small subjects like cup corals or clown fish easily.

Autofocus is as reliable underwater as it is in air. It usually allows you to shoot subjects at any distance from a few centimetres away to infinity. If a subject moves away or towards you the autofocus can normally track it.

Entry level film cameras are restricted in their choice of lenses and how they can be used. In turn, this restricts the kind of picture and subjects that you can take. Most entry level film cameras have a semi wide angle lens fitted as standard. They may be fixed focus, typically operating no closer than 0.5 of a metre. This is too wide a lens and too distant on minimum focus to fill the frame with small animals like many reef fish. Some lenses have to be focused by guess. This should yield a sharper image, but creates additional problems. You need to guess the distance accurately and it takes time to do. If both you and your subject are moving it becomes even more difficult to get right.
Only a small number of entry level film cameras accept wide angle lenses. Without access to these lenses many subjects are off limits including close focus wide angle pictures, large subjects like Whale Sharks and Mantas and anything but close ups in low viz.

Most entry level cameras do accept close up and macro lenses. Normally these use framers to delineate the area that will be in the picture. These have to be placed over the subject. Not surprisingly many animals will not tolerate these and flee. You are also restricted to shooting this one image size. There are restrictions on how close you can get, precluding very small subjects that are easily handled by digital cameras.

Advanced Technology

Underwater film cameras tend to be pretty basic. They occupy a small, niche market. There is little money for development and consequently these cameras have lagged behind their terrestrial counterparts. Digital has widened that gap even further.
 

Taking advantage of the volume marketplace has enabled digital camera manufacturers to increase specifications while actually reducing prices to the consumer. So many digital cameras offer a choice of exposure modes, such as program for getting started, alongside shutter or aperture priority or full manual for those who wish to take more control. You'll often get exposure compensation for overcoming tricky lighting conditions and a choice of flash modes including slow sync for introducing movement to your images.

Control of the Final Image

Shooting prints has normally placed the photographer at the mercy of the developing and printing lab. Some are very good indeed. Others are not. The colour cast in underwater shots often seems to confuse automatic printers and the final results can be lacklustre.

Digital photographers can control the look of their images by using software such as Photoshop. Using simple programs you can alter the brightness and contrast of your images, enhance or change colours, remove or add subject matter and crop to your personal taste. They can also print their own pictures inexpensively.

Low Shooting Costs

Digital is a very low cost way to shoot underwater pictures. Storage media, unlike film, can be used over and over again. It costs only electricity to view your results on your computer. Film has to be processed, which can seem quite expensive for the number of shots you are likely to want to keep. 
 

You also have almost unlimited shots per dive. You can literally take hundreds of pictures on a single card. With film you are typically limited to 36 frames. If you want more pictures you need to take additional cameras down with you. With so few shots available, film photographers have to think very carefully about taking risks. The digital photographer has no such concerns. You can try for a shot that might not work out and simply delete it if it fails. But equally you might end up with a truly excellent image.

Building a System for Effective Underwater Digital Photography

Digital users can choose from a rapidly expanding range of accessories. These include flashunits, strobe arms, filters, macro, wide angle and even Super Wide lenses.

Before plunging ahead and investing heavily in accessories it is important to think through whether they actually offer significant benefits for the kind of photography you want to do.

At Ocean Optics we take underwater pictures ourselves using equipment that we sell. By working with a range of underwater cameras and accessories we can talk you through the strengths and limitations of different set ups. Especially if you are just getting started, you may be surprised at how often we advise our clients NOT to buy accessories!

The reason for taking the minimalist approach is that entry level digital systems are extremely versatile as is. So they are much less dependent on add on equipment to get good pictures. That said, for certain types of photography and in some conditions, additional equipment can make your picture.

Over the next few pages well provide a guide to some of the equipment available and its applications.

Do You Need A Flashgun? No, Yes and Maybe....

You don't automatically need to buy a separate flashgun or strobe. These shots were taken using only the built in flashgun on an Olympus C5050. Built in guns work very well for close up pictures, even in poor visibility. In clear conditions you can shoot over longer distances without incurring the dreaded backscatter.

Built in guns have their advantages. The light is always aimed at your subject, exposure is automatic and there is no additional bulk and drag.

Separate flashguns are needed in low visibility conditions. To avoid backscatter, light reflecting off debris between the light source and the subject, you have to move the light source off the camera. Typically you'll want to get the strobe 30 cm to 45 cm off the camera. "Built on" strobes provide a little additional power, but do nothing to reduce backscatter.

Separate flashguns may also be essential with some add on lenses that can obscure the built in strobe. For extreme close ups off camera flash may also be needed to light your subject evenly. 
Built in flashguns provide only one kind of light - full frontal. If you want to light your subject creatively to enhance textures or create a mood, then an off camera flash will let you do this.

Strobe or Video Light?

We supply our commercial diving clients with digital inspection systems. Typically these divers have to work in very poor visibility. Also it's the nature of the commercial diving world that divers are often presented with equipment with which they are unfamiliar and told to " dive it". It's also likely that the equipment will be mistreated.

We usually supply commercial operators with Kowalski video lights. They need little maintenance, require the minimum of assembly, as they are cable free and, in the rugged environment of working diving, have fewer failure points than a strobe system.

The downside is that a videolight that provides sufficient light for general photography (around 50 watts or so) for a reasonable length of time (say fifty minutes) will be heavy and bulky. This can make them a pain to travel with. Lights that are heavy in the water also require quality arms to properly support them - which are expensive. Video lights will also need to be recharged regularly, perhaps even between dives, and this will usually take a minimum of three hours. Many lights take much longer. If you make multiple dives this becomes a major consideration.

On balance we believe that most underwater digital photographers are better served by using underwater flashunits, rather than videolights.

Choosing a flash unit

Digital stills cameras don't automatically operate well with all flashunits. If you already own an underwater film camera then it is quite likely your existing strobe won't work well (or at all) with a digital camera.

Digital cameras present two problems for flashgun designers. Firstly, they don't measure the light in the same way as film cameras. That has meant going back to the drawing board for underwater flashgun manufacturers.

Digital cameras put out a series of pre flashes to determine correct exposure. Many digital cameras and housings cannot easily be wired to an underwater strobe. So the strobes have to be fired by a slave. The light from the cameras own strobe triggers the underwater gun. With film cameras it is relatively simple to slave a strobe. The triggering strobe fires once and the slave fires with it.

With pre flashes it is more complicated. The slave gun has to fire at the right time. So it has to fire in sync with the final flash from the built in gun. Complicating things further, the number of preflashes isn't standardised.

To get over this, some guns are designed with high speed recycling - they simply fire with all the preflashes and the main flash. Others offer a programmable feature that can be set to ignore preflashes.
Another issue is putting the right amount of light on to your subject. This is less of an issue with film cameras because print film is easily manipulated and corrected at the processing stage. So for entry level film cameras a simple flashunit with just one power setting is usually adequate.

Digital cameras require much more accurately controlled lighting. There are four principle methods of getting the right exposure with off camera strobes. It is important to understand the differences and to thoroughly check the small print to confirm the strobe you are considering really does operate the way you think it does. At the moment we feel that some manufacturers and suppliers are creating confusion by claiming greater degrees of automation than their guns strictly provide. It also does not help that the industry has not standardised terms to describe how strobes work and what they can and cannot do.

Ocean Optics Quick Guide To How Digital Strobes Work

Manual. Manual flash units do not provide automatic exposure. If you use a gun designed for a film camera, and can get it to sync with your camera, you may be able to get good exposures. However it takes experience and skill. Usually a strobe designed for a film camera has only got one to three power settings. This does not give you a lot of discretion for shooting at different distances or for adjusting for different shades and reflectivity.

A manual strobe for digital cameras will usually have six or more power settings. Like the dimmer on a light switch, having so many choices gives you lots of scope for lighting all sorts of subjects over a range of distances, from supermacro to distance shots.

To shoot with a manual gun, you take a picture, review it and then adjust the power of the gun until you have the exposure you like best. With a little bit of practice it becomes much less hit or miss than it sounds! You'll probably get the exposure right first time more often than not. However it is a problem with moving subjects that keep varying their distance, because you have to change the power settings in time to their actions.

Auto

Auto guns use a sensor built into the strobe or attached via a cable that measure the amount of light that the strobe puts out and quenches it when the subject has received enough light. Auto strobes were used on film cameras until the early eighties, but were not overly popular. They have only been recently reintroduced for digital users. Auto sensors have some limitations. You have to work with your camera set to a specific aperture. If you change the aperture setting you must remember to change the aperture setting on the gun as well so both match. There may be limitations on the apertures you can use and on the film speeds you can select. These may not be the best settings for your water conditions and subjects. The sensor can also be fooled by being poorly placed. For example turning the gun inwards to light a divers face who is slightly off to one side, while the sensors is pointing directly out into mid water. In this case it may not "see" the main subject and deliver a poor exposure. Backscatter can also fool sensors and create inaccurately exposed pictures.

Camera Controlled Flash

Our definition of a camera controlled flash is a system where the cameras own internal flash is used to control the exposure of the slaved gun. To do this a fibre optic cable is placed in front of the cameras own flashunit. When you take a picture the internal gun fires and triggers the external gun like an ordinary slave. The camera sees a burst of light and assumes it came from it is own gun. When the camera determines that the subject has been properly lit, it turns off the built in gun. This in turn shuts off the external gun, ensuring a properly exposed flash picture that is fuss free and consistent.

Because the sensor that controls the flashgun is built into the camera you cannot miss aim it. It is also less prone to being affected by backscatter as it is not normally in line with the strobe. A further benefit is that if your camera has a flash compensation feature, this will also control the external strobe as well. This can be useful as it allows you to customise the exposure to your taste. For example if you photograph divers it is quite common for the auto exposure to be fooled by dark equipment on their bodies. This causes the automatic exposure to boost the flash power to compensate. The result is that the divers face is often greatly overexposed. By setting the flash compensation exposure to underexpose a little, this problem is solved. If your camera does not have this feature you'll find it provided on some underwater guns. These are normally just selected on a dial and can be faster to use than a menu based selector.

Also because the external gun is controlled directly by the cameras own built in gun, adjustments made to the camera are automatically relayed to the strobe. If you alter the aperture or film speed there is no need to make any additional adjustments to the strobe. So there is almost no scope for making an error by being forgetful or narced.

Camera controlled flash is our recommended solution for working with currently available consumer camera and housing combinations represented by Olympus, Sony, Canon and similar own label suppliers.

TTL/D - TTL

TTL and D - TTL are the most sophisticated flash control systems available to digital underwater photographers. They are most commonly used with digital SLR cameras such as the Nikon D100, Canon D30, D60, D10 and Fuji S2 Pro.

These camera and housing combinations let you hardwire your flashgun straight into the cameras own hot shoe. The cameras through the lens (TTL) meter controls the exposure from the strobe. This is a highly dependable and accurate method of both firing your strobe and getting perfect flash exposures. Because metering is through a sensor mounted behind the camera lens it is unaffected by the field of view of the taking lens and it always sees the main subject.

Currently Nikon and Canon digital SLR cameras require that you use a Nikon or Canon D- TTL strobe in a housing for automatic flash control. The Fuji S2 Pro works with ordinary underwater strobes.

Because the flashgun is wired directly into the camera, rather than working as a slave, camera manufacturers expressly warn against using strobes supplied by other makers. Doing so will almost certainly void your warranties. Similar reservations were expressed when independently manufactured strobes were made available for the Nikonos range and when 35 mm SLR owners used unofficial strobes with their housings. Time will tell if these concerns are justified...

Masters and Slaves

Slave is a term you'll commonly hear bandied about by underwater photographers. It refers to any additional flashgun that is triggered by the burst of light from another gun (the master, which is connected to the camera). Slaves are often used to light creatively. For example you can hide a gun behind your subject for rim lighting, or you can give a slave to a diver who is modeling for you to make it look like they are holding a powerful torch. Cave photographers often attach rear facing slaves to other divers in order to light cave passages behind them and add depth to their images.

One Strobe Or Two?

If you are just getting into off cameras strobe photography, we always recommend that you work with just one gun. Two guns add bulk and cost and usually require more skill to shoot successfully. Basically, if you are new to underwater photography, two strobes are probably more trouble than they are worth.

Two guns are useful when working with extreme wide angle lenses in dark conditions, such as inside a cave. This is because a single strobe usually does not have enough spread to cover lenses wider than a hundred degrees. In this case the second strobe is used to simply provide additional spread to avoid hot spotting and dark corners.

In bright open conditions it ís often perfectly viable to light even a superwide lens with a single gun. Any fall off at the edges tends to blend with the sunlight and looks quite natural.

For creative lighting using a pair of guns can let you light from two angles to create or reduce shadows or to use back or rim lighting. Getting creative with your lighting angles can lift a picture by providing much greater impact.

Finally, many top underwater photographers swear by one or two strobes and won't be swayed in their opinions. So there ís no cut and dried answer as to how many you should use.

Strobe Arms

Often overlooked and undervalued, strobe arms deserve some careful consideration. Basic strobe arms are often supplied with strobe packages to keep the purchase price low. Typically they place the gun to one side of the camera lens and slightly above it. This works fairly well in clear water, but will create backscatter in turbid conditions. This fixed position provides little benefit over using the built in gun for shooting with the standard lens or close up accessories. If you use wide angle lenses in clear water it does work quite well in our experience. Built in guns do not usually work satisfactorily with wide angle lenses as the coverage is not matched and often the lens obscures part of the flash. Both scenarios lead to dark patches in the final picture.

If you want more flexibility to light your subjects you can either hand hold your strobe or use a more versatile flashgun arm. Some basic arms cannot be updated and you'll need to buy a new arm altogether. Others are designed to accept extension sections and clamps, allowing you to build on your system at relatively low cost as and when you feel your photography requires it.

Wide Boys

Wide angle lenses serve three main purposes. They let you shoot large subjects, operate in low visibility and manipulate perspective.Water has two main effects on underwater photography. It isn't really clear. Even crystal clear water only equates to a foggy day topside. The debris in the water column physically obscures your subject, making it look soft or out of focus. The more water you have between your camera and the subject, the worse the picture looks.

To keep the picture sharp, you need to get as close as possible to your subject. By reducing the water column between your camera and your subject, you also reduce the amount of detritus you have to shoot through. With large subjects like whale sharks and wrecks, a wide angle lens is essential for good photography.

The second effect of shooting through water is that it quickly absorbs colour. Youíll only get bright reds, for example, in shallow water over short camera to subject distances. To counter this flashguns are often used. However flash has a limited range through water. So getting close, even with flash or video lights is also vital to capturing vibrant images. Wide angle lenses let you get close enough to large subjects, like other divers, to get good colours.

In low visibility, wide angles become vital for anything other than macro and close up photography. In the typical conditions found in the UK, you might have to photograph large subjects like your buddy from under a metre away. Wide angles let you do this.

Wide angle lenses also let you play with perspective. Close focus, wide angle, is an example of this. By placing a smallish subject in the foreground a few inches in front of the lens you can make it tower over a diver just a little further away. Half and half shots or split levels are also possible with some set ups.

For consumer cameras, wet lenses are readily available. These either screw directly into the housing or mount via an adapter. They can be fitted and removed underwater in a matter of seconds, providing great flexibility. Holders let you store your lenses safely, usually on your strobe arm.
Wet lenses can sometimes be used in air. Typically they cover 85 to 100 degrees - roughly equivalent to a Nikonos 20mm or 15 mm lens. The exact coverage will depend upon your cameras own lens.

Prosumer cameras like the Nikon D100, Fuji S2, Canon D30, 60 and D10 use normal land lenses placed behind special ports attached to the housing. You need to choose your lens before the dive.

Macro Lenses

Most consumer digital cameras have a macro or extreme close up facility built in. This lets you photograph tiny subjects like Nudibranchs or Porcelain crabs for instance. However there may be limitations on how close you can really shoot underwater because of flashgun limitations. Some cameras donít permit the use of flash at very near distances because the flash cannot light the whole frame evenly. In this case an off flash will not work because there ís no flash from the camera to
trigger it.

Macro lenses usually attach to your housing via a screw thread or an adapter. They allow you to shoot from further back while still filling the frame. This lets you use your built in flash or an off camera strobe as you prefer. You can also use much of your zoom range for more control over the final composition. Keeping your distance also helps to avoid damaging coral and can make shy creatures easier to photograph.

Prosumer cameras use macro lenses that are designed to provide a continous focusing range from a few centimeters away to infinity. For even higher magnification Prosumer camera owners may add teleconverters or close up lenses.

Buying from Ocean Optics - What to Expect

If you buy from Ocean Optics and can call in, we will want to spend time going through your housing set up with you. During your visit we will check that all the controls on your camera and your housing have linked up properly and are operating correctly. Optics has decades of experience of working with housings, both as retailers and as manufacturers. Based on our knowledge of housed cameras we don't assume everything will match up perfectly first time. Especially if this is your first underwater camera, we will also want to spend time demonstrating the steps you will need to follow to ensure the ocean stays out of your housing and camera. We'll also explain the rationale behind the precautions that we recommend. O ring handling and pre dive testing are just two of the subjects we will cover with you.

This is also a good opportunity to ask us any questions that you have about shooting techniques.
Typically going through all of this will take around 20 minutes.

Ocean Optics do not supply cameras. We honestly feel that there are people out there who can offer a much better service on land cameras than we can. We recommend that to discuss your shortlisted cameras in detail before making a final decision you should talk to a local camera specialist that, above all else, you trust!

A good camera specialist will be able to offer three important benefits. A fair price, which is self explanatory, product knowledge and aftersales. We'll expand a bit on these last two qualities. At any given time Optics can house over forty different models of digital stills camera. The lifetime of most of these cameras is measured in months. It simply isn't possible for us to know all of these camera types as well as a good camera dealer with access to product training and dealer support. We can advise in terms of which models work well under the water. But most of our clients will use them more on land. So it ís often very important to ensure the cameras you are considering will meet your topside requirements in full. This is where a specialist dealer can prove invaluable.

Aftersales is something that is regularly overlooked. We like to consider ourselves to be very attentive to the needs of our clients long after they have bought their equipment from us. We generally do not work with Britsh distributors. Usually we import equipment direct from the manufacturer. By removing the distributor from the chain we do not have to depend upon them for aftersales. Our experience of dealing with UK distributors was that while equipment might be readily available, parts for carrying out repairs and even essential consumables like spare O rings were not!. By taking on resposibilty for back up ourselves we can do a better job for our clients.

If we supplied land cameras we would not be able to service or repair them in house. As a small company we would also be unable to apply much pressure to the larger camera distributors to sort out problems. A good camera company would have the leverage to fight your corner.

If you don't have a specialist photographic dealer near you, and this seems to be increasingly the case, we are delighted to recommend our colleagues at London Camera Exchange. Youíll find that the crew at LCE have an extremely thorough knowledge of their vast product range and are all highly experienced digital users. You will emphatically NOT get the hard sell, or any bull.

On a Tight Budget?

Underwater digital systems are very inexpensive for what they offer. But if you are trying to keep your costs down to the bare minimum itís worth checking with us on the availability of discontinued lines. The speed at which digital cameras are currently being introduced and deleted by manufacturers often means that camera prices are slashed when a model is discontinued.

Working closely with London Camera Exchange means that we can often offer super deals on older camera/housing combinations. In digital terms older may mean only a matter of a few months. Changes to camera designs are increasingly minor and rarely important for underwater photography, so buying a cameras that is not the absolute very latest isn't likely to compromise you at all. LCE also offer a trade in service that may be helpful.

About Own Label Housings

It ís very rare for a camera manufacturer to design and build their own underwater housings and accessories. For 35mm and medium format film cameras it's usual to have to look for an indepndent housing maker. The camera manufacturer does not normally have any ties to the housing company and usually does not offer any cooperation.

With digital it ís very different. An increasing number of camera manufacturers are providing housings under their own label. Usually the design and manufacture of these cases is subcontracted to a small specialist designer.

The digital revolution has been very good for consumers. Divers have especially benefitted. The housings on offer by camera companies are not specifically targeted at underwater photographers. They are chiefly aimed at outdoors photographers such as snow skiers, kayakers, boaters and people working in humid environments like jungles. These markets are much larger than the diving market and, for the first time, have allowed us to gain from mass prodution techniques. To put this into perspective consumer digital housings are built in the low thousands while housings for 35mm SLR cameras may have production runs measured in tens of units. The cost savings are enormous and has made quality underwater housings available to divers very inexpensively.

Because underwater photographers are not the main market for own label housings, there ís little development of accessories for divers being initiated by the main camera players. For these you will normally have to look to indopendent manufacturers. Again, this is a common situation for underwater photographers. The classic Nikonos camera is a good example. Nikon only ever made a small number of accessories for this camera. It's versatility was enhanced by the far greater range of products developed by small manufacturers, including Ocean Optics.

However working with independent manufacturers can have its pitfalls. The huge range of camera and housing combinations can make it hard to properly test the compatibility of lenses in particular. Each time a new camera and housing are introduced, the system really needs to be tested with the existing lenses. The reality of small company production techniques means that lenses cannot perpetually be upgraded each time a new rig appears. With many housings, filter threads are not fitted. This oversight means that to attach filters or lenses you will need an adapter built by someone else. Using adapters has the potential to create problems with your optics, so itís important to talk with us before investing in additional lenses to confirm compatibility.

Similar issues can occur with strobes as touched on in our guide to strobes, it ís vital to ensure that your flash unit and camera are properly matched to avoid problems with exposure and pre flashes.

Not all indpependent accessory manufacturers abide to the stringent quality control standards imposed by companies like Olympus, Canon and Sony on their own subcontracters. This can lead to diappointment in the performance or reliability of your new accessory. Our experience is that housings that carry the name of the camera manufacturer themselves are intrinsically reliable.

Similarly with newer companies that have yet to establish either themselves or a UK dealer or distributor there can reasonably be concerns over aftersales. Routine servicing and occasional repairs are a fact of life for underwater photographers and it ís risky to overlook its importance when selecting your equipment.

On the plus side some very innovative equipment is being designed for use on own label housings. This is quickly taking consumer digital systems out of their original role as clear water snap shot cameras and placing them in a realm where they easily achieve images previously taken on film cameras costing thousands of pounds.

 

Steve Warren