Digital Cameras, what's so special?

Underwater, digital cameras have a number of advantages over film cameras. Probably the greatest is that you can see the picture you just took. While the preview screen on the back of the camera is small, it is enough to let you know if you got the shot, should try again, or not bother, and makes exposure bracketing much less necessary.

Another advantage is that you can delete bad shots right away. This allows you to shoot many more shots per dive, and significantly raises your percentage of "keepers". Memory cards for digital cameras have become quite large and inexpensive, so that you can easily have 100 shots or more for every dive, compared to 24-36 for a film camera. The CCD sensor that is the heart of a digital camera also has better low-light capabilities than most film.

Most zoom lenses on digital cameras have excellent close-focus settings. Underwater, this gives them on-demand macro capabilities, unlike most conventional underwater cameras which require special lenses to be installed before-hand, and then used throughout the entire dive. The digital camera's LCD viewer makes macro composition easy, so that with a single camera and lens you can shoot everything from tiny shrimps to humpback whales, all on the same dive!

A drawback with any kind of digital photography is shutter lag. With a film camera, press the shutter button and Click! you got it. With a digital camera, even if you set up the focus and exposure in advance, press the shutter button and ... wait, wait, wait ... Click! you got it - about a half second later. I have not seen any digital camera that is significantly better than any other in this. Long shutter lag makes taking action shots somewhere between difficult and impossible, especially close-up. Nearly instantaneous shots - like somebody jumping in the air - are unlikely to ever come out. For the same reasons, exposure bracketing, as practiced with film cameras, is far less useful with a relatively slow digital camera. So film still does have a place in the world.

Having said that, I would add that the advantages of a digital camera far outweigh the disadvantages, and my convenient little digital camera goes everywhere with me, while my big, expensive, backpack-filling 35mm SLR gathers dust.

Digital camera technology is progressing at a phenomenal rate. Much like computers, prices steadily fall, while features and performance improve. When setting up an underwater digital photography system, first make sure you have the very best and latest top-of-the-line digital camera available. Don't buy a housing for a camera that is already old, or you will find yourself stuck with an expensive combination that is already obsolete, or very soon will be. Get a new camera first, then get a housing for it.

There are 4 inter-related factors in digital camera design:

• resolution - 3-6 MP; most higher-resolution cameras are actually inferior
• storage - for a useful number of hi-res pictures
• lens - without a good lens, high resolution is wasted ( and vice-versa )
• power - to make it all run

Skimp on any one of these, and the whole package suffers. Don't put too much weight on electronic features and doo-dahs ("extra buttons") - you probably won't ever use them anyway.

It is commonly said that with a digital camera, your memory card is your film. This may be accurate, but it's not important. What you really need to be concerned with is your limiting factor - the thing that will run out first - at which point you are out of the picture-taking business. With a digital camera, there are two possible limiting factors: memory, and battery power. As I said earlier, memory cards have become huge and relatively cheap. Memory is no longer your limiting factor - just get a big enough card that you are unlikely to get to the end of it in one session, and forget about it. 256 MB should do for most times; 512 and bigger are available.

Your real limiting factor is battery power. Digital cameras devour batteries at an incredible rate. Most digital cameras use high-density proprietary rechargeable batteries. When a battery like this runs down, you are finished, at least until you can recharge it. Therefore, you should always carry at least one extra set of batteries or one other proprietary camera battery, which will probably cost you about £20 or more. Even then, when the second battery runs down, you are finished. I prefer to use a camera that uses simple AA batteries and I always carry 12 Duracel AA batteries with me as spares, as well as the 12 rechargeable 2600mAH NiMH cells i use on a day-to-day basis and their charger. If you end up without mains power to charge your rechargeable cells, don't panic you always have your Duracels! Canon and Sony are the biggest offenders in proprietary battery use; Nikon and Olympus seem better. On a trip to the Red Sea a fellow diver came without his charger (for a Canon camera) despite having another Canon camera user on the boat, the two battery chargers were not compatible... be warned!

The latest technology in standard rechargeable batteries is NiMH - "Nickel-Metal-Hydride" and is very good indeed. High capacity batteries and 1-hour chargers are available at most electrical retailers (check our 7dayshop and Maplin). As with proprietary batteries, carry at least two sets.

Another advantage of using generic AA-sized batteries is that as the battery (and charger) manufacturers improve their products, as they tend to do, you can upgrade your camera simply by getting the new better batteries and putting them in. The original NiMH batteries of just a few years ago were 1300 mAh (milliamp-hours), while the latest ones are 2600 mAh - a 82% improvement, while at the same time the price dropped. Compare with the "upgraded" proprietary lithium-ion batteries now available from Canon - 0% improvement for £60. With proprietary batteries, you are pretty much stuck with what you have, and the only future possibility is that they will someday become unavailable.

In my opinion proprietary camera batteries and memory are nothing but a rip-off, be very careful when choosing your digital camera, believe it or not the availability of batteries is just as important as the availability of a decent underwater housing.

One problem with using digital cameras under local conditions is cold water. Digital cameras rely on electricity for 100% of their operation, and require a good source of power for proper operation. At low temperatures, say below 40F, most types of battery function poorly if at all. This includes throwaway alkalines, NiCads, and especially NiMHs. What that means is that after a brief cold-soak, you may find your camera operates very slowly, or not at all. Lithium-ion batteries do not have this problem, so for those situations you may want to pick up a set of throwaway lithium cells (Duracel are a good make!).

Underwater Housings and Lights

This is where it all gets confusing, there are many different housings available for each and every popular make and model of digital camera, for instance the Olympus c5050zoom i own has a choice of 4 housings, one by Olympus, one from Light and Motion, another made by Ikelite and a fourth by EW-Marine (although it must be mentioned that the latter is merely a plastic bag with a watertight seal!!). The choice of housing is determined by budget and by the functions you want the camera to perform. Most housings will allow complete control of every camera function, be warned, make sure you can turn your camera on and off underwater, funny as it may seem this is an important issue that must not be overlooked.

The choice of housing is then split between inexpensive poly carbonate (plastic) and metal (alloy). As a rule alloy housings are about 4 x the cost of the inexpensive poly carbonate models and are only really a choice for the hardened professional or if you really think that the poly carbonate model is not up to the rigors of your diving practices.

All housings have optical glass ports on the front to allow you to shoot clear photos and focus through the housing and many will allow the addition of supplementary wide-angle and macro lenses as well as colour filters to the outside which are often removable underwater.

I am not going to plug one brand of strobe or another, I have had good and bad experiences with all makes of strobes, however Inon, Ikelite and Sea & Sea are the three contenders for the underwater strobe crown. If you can afford them they the right tools for the job. You can get less expensive alternatives, a strobe by Epoque for £149 will give you light at the right time but not always the amount you really need or want, if you can get an automatic (TTL) or semi automatic strobe spend the extra cash you will be rewarded by the number of shots that work fist (well maybe second or third) time. Don't be afraid to spend too much on your lighting system, because unlike the camera / housing combination, your strobe lights will not soon become obsolete. If you invest in the new Ikelite digital strobes and wireless TTL slave sensors, or the top-of-the range Sea & Sea auto strobes you can transplant them onto any future camera system you get, digital or film, and get many years of use from them. Whatever you get, make sure it's compatible with your camera system, most, if not all digital cameras use a pre-flash system to calculate exposure which for some daft reason is not disabled when you switch the camera to manual mode so make sure you get DIGITAL-compatible strobes, otherwise your strobe will trigger with the first (pre-) flash and not have time to charge before the second flash and the shutter opening (about 0.1 seconds later). Some of the newer digital strobe system attach directly to the camera via the hot shoe and work as TTL off the camera, therefore you can have correct exposure every time and perfect strobe sync, however these systems are still in development and are not 100% reliable yet.

Some prefer two small strobes to one big one of equal cost, i use one big strobe for ease of transport and setup although a smaller slave strobe would be a welcome addition to my setup.. With two strobes you have many more options: you can widen the area of illumination for larger scenes, overlap them for more intense spot lighting, or shut one or the other off for special effects. Use of dual strobes also avoids the strong dark shadows that are inherent with single strobe use. These underwater slave strobes could also be used topside with a suitable strobe tray for the camera. As I said earlier, your lighting system is at least as important as the camera itself, so if you have extra cash, spend it here!

Once you have chosen your strobe you have to get an arm and base plate to attach it to eh camera housing, these range in price from £40 to £300 and vary by their customisation and flexibility. if you want to do only macro shots a short flexible arm will suffice, if you are looking to do wide angle shots you want to put some distance between your camera and strobe, so think of getting a long arm with a few "bend" points in it like the Sea & Sea Sea arm VI or the arms made by Ikelite, these allow yo the best of both worlds but come with a corresponding price tag.

Other Features to look out for

Once you get a housing for a camera, you are stuck with the pair, so make it a good camera. Other features to look for include:

• a good quality, all-glass, fast ( f/2.0 or better ) 3x optical zoom lens
  a big bright rear display - at least 1.8" diagonal
  a decent-sized body that fits comfortably in your hand - don't go for one of the cute little mini models
• Availability of a purpose built underwater housing rated to at least 40 m

Digital camera technology is changing so fast that any specific recommendation made here would be out-of-date in three months. My own preference among manufacturers is Olympus. Canon can also be recommended (although look out for their batteries!).When I bought it, my now-outdated Olympus was the best thing on the market. For some excellent reviews and background information on digital cameras, take a look at Steve's DigiCams, the Digital Camera Resource, and Digital Photography Review. I have found in the past that printed magazines are far less useful, you can get a lot more info from the Internet and talking to other underwater photographers than you can from a 70-page monthly magazine! For an almost complete selection of underwater housings and accessories, please visit Cameras Underwater.

If a digital camera is like a computer, (in fact, they are little computers) then how long a useful life should you expect from it ? I'm not talking about how long until it breaks, but, like a PC, how long until it becomes inadequate for your expectations. I would say that the technology reached a useful plateau at 3-4 megapixels, and a camera of at least this resolution should be adequate for most uses for at least 3 years. At that point you will be able to buy a new one that is half the price and three times the resolution, and you probably will, regardless of the condition of your old one.

Given current price trends, your camera housing is soon likely to cost significantly more than the camera inside. Both pieces are useless if either one wears out, but this is especially true of the housing, which is very likely to outlast the camera. Digital cameras seem to have a model life of a year or less. Some camera manufacturers (Olympus in particular) re-use the same basic body design in new models, others do not (Canon, Nikon). If this is the case for yours, you may be able to replace the camera in your housing with a newer one later. Otherwise, your camera housing will be pretty much useless without the original camera it was made for - the port, mounts, and controls are never going to match up with a different camera. Therefore you may want to pick up an extra camera for a spare, or get yourself a comprehensive insurance policy to replace BOTH should you have an unexplained flood or have one stolen/lost. However, if you wait until the end of the model-life, you can often pick up a brand-new one at a significant discount just before it is discontinued. Otherwise, eBay is a good place to look for a used one.

Digital Image Jiggery-pokery (editing)

One of the great advantages of digital photography is the ease with which the resulting photos can be manipulated and improved later using your computer and an image editing program. Of course, you can also do this by scanning film prints or slides, but dealing directly with digital images is faster, easier, and virtually free.

Underwater photos ( film or digital ) may suffer from the following problems:

• lack of contrast
• lack of sharpness
• excessive darkness or light
• loss of red tones / poor color balance
• poor framing and composition

With a digital image, all of these are easily corrected, within reason. It is often possible to turn a poor shot into a usable one, and a good shot into a great one, using image editing software. My favorite program (for PC) is Photoshop, but there are other programs available for free or for considerably less. Windows XP even comes with a serviceable if limited image editing program for free.

As with all digital photo editing software, color controls can directly adjust darkness, contrast, and color balance. There are filters to automatically sharpen, soften, and blur images, and tools to rotate, crop, and resize your images. In addition, Photoshop also contains a host of digital painting tools. All the images on this website, whether scanned or digital, were edited in Photoshop.

• Colour Balance - to restore the "natural" colour of an image, many underwater images lack the vibrance of the original scene: add a little red, take some of the blue out, play and you will see what i mean.
• Crop - to remove extraneous parts of the image and focus the viewer on the intended subject
  Resize - usually to make a smaller image, for use in a web page, or to send in email

Another function that can be useful for underwater images is grayscale. Use this to turn an overly green image into a normal-looking black-and-white one when other color manipulations fail. Our eyes see black-and-white under low-light conditions, and this looks much more natural in a photo than shades of green.