John Bantin has been a full-time professional diving writer and underwater photographer since 1990. He makes around 300 dives each year testing diving equipment.

DIGITAL CAMERA
Sea & Sea DX5000G
IT'S FUNNY HOW LIFE SO OFTEN FAILS TO LIVE UP TO EXPECTATIONS. People buy four-wheel-drive cars that will go anywhere apart from through the traffic chaos caused by an inch of snow. They buy electronic washing machines but still find that one rogue red handkerchief can ruin all the white washing.
     People still try to take photographs of firework displays using cameras with a built-in flash. And that brings us to the marvels of digital photography.
     No skill needed - just point-and-press for perfect results. It's a seductive sales pitch. It's true that modern digital cameras grab pictures that never got to see the light of day when taken with simple, old-fashioned film cameras. Stick one in a waterproof case and it's "David Doubilet, eat your heart out".
     But in fact it's often another Range Rover unable to get up Barnet Hill for the sheer weight of stopped traffic, and not at all what the salesman cracked it up to be. First off, these inexpensive little digital cameras are not as good as those that cost five big ones. How could they be? There are always snags.
     That said, if all you want are personal pictures with which to impress your friends, compact digital is the way to go.
     However, even those new digital divers who take a more thoughtful approach to capturing images of their subjects may be disappointed. They might as well be armed with an endoscope, because so often all they get is the rear end of an animal as it beats a hasty retreat. The world must now be awash with pictures of fishes' bottoms.
     Shutter-lag is the reason. Most of these little cameras need time to readjust from making an image on the LCD screen to recording an image on the media card. The delay can be long enough to make all the difference.
     Sea and Sea claims a shutter-lag of only 0.12 second for its 5.1 megapixel 5000G camera, which comes as the DX5000G when supplied with a 55m-depth-rated underwater housing. That's the sort of reaction time only a mantis shrimp could beat.
     When all around it are really only cottage industries, the Japanese manufacturer Sea & Sea is a giant in the underwater photographic equipment world, and it should know a bit about it by now. Hence the shutter-lag problem has been solved, or so it claims.
     It also addresses a couple of other problems that cannot be solved any other way, whatever other manufacturers may say.
     Firstly, the worst way to get clear pictures is to have a lot of water between you and your subject, then zoom in to get a good-size image. You should be getting as close as you can and using your camera at its widest-angle setting to compensate.
     Sea & Sea allows the use of a wide-angle conversion lens that fits directly to the front of its housing. Digital zooms are a waste of space. They simply enlarge part of the image with increased pixilation and reduced clarity.
     Secondly, the light you get from the surface once it's been filtered through a few metres of water is quite monochromatic. You can increase the ratio of red to blue light by changing the white-setting on some digital cameras, but not enough to get results rich in colour. The quality of light can really be enhanced only by taking some full-spectrum light with you under water.
     Unfortunately, the on-board flash of these cameras is without exception positioned too close to the optical axis of the lens, resulting in all the detritus in the water being lit up, to the disadvantage of everything else. The only useful function of that inboard flash is as a trigger for a proper external flashgun.

Water and electricity
Sea & Sea supplies a range of external flashguns that can be mounted singly or in pairs on a variety of brackets, for full colour photography at depth. Not only that, but they are linked to the camera by flexible fibre-optic cables, avoiding any problems of mixing water with electricity.
     The camera has two connection points so that two flashguns can be used simultaneously. I teamed up a DX5000G with a neat little YS-15 Auto.
     The other problem encountered by users of simple digital cameras is that, without the proper viewfinder system of a digital SLR, you need to rely on the LCD image for lining up your shots. This normally works fine in air, but under water often the LCD is hard to see because it gets as much ambient light falling on it as on the subject, and often more. Sea & Sea provides a deep hood for the LCD display. Another possible problem solved.
     What these little digital cameras are naturally good at is close-focusing, because the zoom lens provided can be turned inside-out to focus really close. The DX5000G will focus on something as close to the lens as 10mm. That's close. Its zoom is only 3:1 but, believe me, you don't need a zoom under water.

Add media card
With the ability to record on a 5.1 megapixel chip, the DX5000G can produce as good a result as its nine-element optics will allow. However, if you use only the internal 16Mb memory, that's one picture at this quality. You need to add a media card (not included) and it takes SD Memory cards or MultiMedia cards.
     To take full advantage of the recording quality, you will need to shoot in the TIF uncompressed file format, but that means only around 53 shots on a 512Mb card.
     If it's "never mind the quality, feel the width", you can shoot "normal" quality jpegs and get more than 1000 shots on an optional maximum-size 512Mb SD Memory card. Either way, if you can download the shots you have taken between dives, it should mean never running out of shots under water.
     I'm not going to bore you with much else that's technical. That's what instruction manuals are for. As for the manual - I read it! I found it was easy to understand, and setting up the camera to my own configuration was straightforward.
     What I will tell you is how I got on with it during a week's trip on mv Tiger Lily in the Red Sea.
     What I immediately liked about the DX5000G was the fact that the buttons on the back of the housing are understandable even when you're befuddled by breathing air at 50m. I also liked the fact that the LCD monitor hood was made of thick rubber compound that was robust enough not to fall off during a dive.
     The manufacturer makes no pretence of expecting divers to look through the little optical viewfinder, and this is blocked off.
     Under water, you can still easily access the control which allows you to switch from camera-shooting to play-back or even to main set-up mode. Many housings for cheaper digital cameras don't allow that.
     I put a bit of black tape over the window of the built-in flash to prevent backscatter, but the remotely controlled diffuser was still able to trigger the external flash.
     Pressing the close-up button brings super-macro shots easily into focus, even though the lens is so close to the subject that it sometimes proves difficult to get the light from the flash in the gap between lens and subject.

Hoorays and boos
So much for the promises. What about the disappointments?
     First, to record a high-quality uncompressed TIF file after you've shot it takes a minute or more. That means the camera is out of action while you wait for it to do it - very frustrating. I quickly abandoned any ideas about shooting further TIFs, and changed to the highest quality JPEG format instead.
     I managed to stalk a massive ribbontail ray and get off one shot as it passed me. Hooray for the quick grab-time. Boo to the fact that the ray had long gone before the camera was ready to take a second shot. So, quick "grab-time" but slow "file-writing".
     Smaller files take less time to record but mean reduced quality. What the DX5000G proved very good at was taking posed pictures of a co-operative buddy, and that's probably what most of these cameras will be used for.
     What about macro mode? I went to St Vincent, the macro capital of the Caribbean, and tried to photograph sedentary but rather small animals. This generally proved easy because they kept still, but in macro mode the grab-time seems very extended. It could take around two seconds before the main flash went off, indicating when the picture was actually taken.
     I had some fun with a seahorse that was clinging to a stalk of coral that wavered in the swell. I had about 20 attempts at recording it because I could never tell when the camera was actually going to take the picture. The seahorse wavered in and out of the shot and often I merely recorded the space it had previously occupied.
     I had about a four-to-one success rate as my anticipation got better. Using the hit-and-miss method, I still managed to get a lovely close-up of a spiny pufferfish.
     So what's the verdict? This combination digital camera, housing and flash will allow you to take pictures that will look as good as those taken by the professionals. They will have a full spectrum of colour rather than that slightly monochromatic "digital look" obtained by cheaper alternatives. It is exceptionally effective for close-ups.
     There is still the grab-time to consider. It may not be shutter-lag but there is a delay between pressing the button and getting the picture. You need to get accustomed to it before success is assured.
     Sea & Sea provides downloading software for PCs and a USB connection lead. In my case, I simply stuffed the SD Memory card into my card-reader and the magic of Mac OSX took care of the rest. Job done! The pictures are not big. Digital quality depends on the size to which you blow them up.
     Underwater photography is never going to be cheap. The all-up price might seem quite a lot but it's around a quarter of the price of a proper pro/am camera, housing and flash set-up.
The Sea & Sea DX5000G complete with YS-25 Auto Flash including mounting stay, bracket and fibre-optic connection costs £1249.

Sea & Sea 01803663012, www.sea-sea.com

+ Properly lit digital underwater photographs + Exceptionally easy-to-use

- Delays, delays!

COMPUTER
Aladin Prime
IMAGINE THIS. I WAS ONCE RETURNING FROM SHARM EL SHEIKH, back in the days when one needed to drive up to Eilat to get a flight from Ovda in Israel. While waiting in a bar in Eilat, a man showed me his new Aladin Pro diving computer.I had never seen one before.
     It was fantastic. It did things that made the few other computers available then look like clockwork toys. Everyone wanted one and very soon everyone had one. It seems like yesterday but it was nearly 20 years ago.
     Times change, and nowhere more so than in the world of the microchip. Although the successors of that original Aladin Pro sold well, Uwatec, under the ownership of Scubapro, surrendered its market leadership to Suunto. A lot of other computers, including those from Mares, Seiko, Cochran and even a British manufacturer, Delta P, arrived for sale in dive shops. One might say that Scubapro/Uwatec had lost its way.
     Now Sergio Angelini has taken the reigns of the diving computer manufacturer in Switzerland. I know him, because I've enjoyed two weeks of his company on a liveaboard. He's young, Italian, competitive, lived for many years in California and there's nothing angelic about him! It's no coincidence that a whole raft of new Uwatec computers has arrived at the same time.
     One reason that other computers became so popular was that they allowed users to change the battery safely themselves. Because Aladins needed to go back for the distributor to perform this task, battery changes tended to be expensive. Users carried on using their computers until they failed, rather than getting a battery changed in good time.
     All the other computers on the market have a user-replaceable battery installed in an integral watertight compartment. Do a bad job and you lose only the battery, not the computer. The new Aladin Prime now follows this trend and I believe it will be the major difference that will make the company competitive again in this market.
     The Aladin Prime is also set up using buttons. Hooray. That wet-finger business drove me crazy. It also displays date and time when not being used for diving, and it has an independent back-light for its display. These were all the features that I thought were missing in the old Uwatec computers.
     Now there is an Aladin Prime and an Aladin Prime Tec. I am going to tell you about the entry-level Aladin Prime. The first problem I encountered was an instruction manual that catered for both and which was therefore quite confusing to digest.
     The fact is that the more expensive Aladin Prime Tec offers many more options than the Prime, but that's another story. Suffice to say that new purchasers of the Prime will quickly wish they'd bought a Prime Tec if they get seduced by the manual.
     On the other hand, if you are the sort of diver who lets the shop set up your computer for you and simply strap it to your wrist and go diving, the Prime is for you. Get a dive-professional, your dive-guide, to change the nitrox mix when you need to and never bother to read the book. You'll probably survive!
     For those more persistent, there is the usual problem of distinguishing between long and short pushes on the buttons, and this takes a bit of getting used to. Persevere with the manual, go through it with a highlighter pen to identify the small part devoted to the Prime as opposed to the Prime Tec, and you'll soon get the hang of it.
     The Prime simply allows you to set nitrox mixes from 21% (air) to 50%. It works at a fixed maximum ppO2 of 1.4bar and is permanently calibrated for use in sea water.

Why turn it off?
It also allows you to set clock and alarm-clock functions and to turn off the activation on contact with the water. I would advise anyone, inexperienced computer-users or not, to avoid doing that last thing. Why would you risk jumping in with it turned off? You can also reset de-saturation logged, but that is mainly for dive centres which might be frequently renting computers to different divers on a dive-by-dive basis.
     The Aladin Prime uses the well-tried Buhlmann ZH-L8 ADT algorithm, which is now thought to be less cautious than some other contemporary European-produced programs, including that of the Prime Tec when set in a reduced micro-bubble mode. However, after 20 or more years, this algorithm has been successfully used without incident by a very large number of divers.
     The Prime also has a safety-stop timer that can be activated after an ascent and when at less than 6.5m. It has to be manually activated. You give a short push to the left-side button and it counts down three minutes, so long as you stay above the stop depth and below 3m and the displayed remaining no-stop time is at 99 minutes.
     Of course, I couldn't remember which button to press when it came to it, but pressing the wrong one caused no problems.
     During the dive, the information was simply and clearly displayed, just as I had expected. The little nitrogen-loading bar graphic is obviously a concession to those markets where divers are not very good at reading numbers! Its variable ascent rate (according to depth) is displayed as a percentage of the maximum permissible. Stay away from 100% and you won't see the word SLOW appear.
     One assumes, as an entry-level item, that this computer will tend to be purchased by those who stay within diving no-stop times. It is a full-function decompression computer, however, and displays stop depths, stop times and total ascent times when in deco mode. It also displays O2 CNS loading, although the typical user will find that this never amounts to much.
     After the dive, information can be downloaded to a PC equipped with an infra-red interface and loaded with the software provided with the Aladin Prime.
The Aladin Prime represents very good value. It costs £219.

Scubapro Uwatec UK 01256 812636, www.scubapro.co.uk

+ Clear, easy to use entry-level nitrox computer + Economic price

- Manual shared with Prime Tec is hard to digest

BC
Mares Vector 1000
WHO BUYS A MARES VECTOR 1000? I guess it's the sort of person who buys a BMW 3 series for domestic duties when a Ford Focus would do the job equally well. It's a very conventional BC but it exudes the look of something quite expensive, and looks aren't always deceiving!
     I get confused with the names of Mares BCs. So many of them are called Vector-something. The men at Mares also love acronyms. This BC has QAS, BPS, SAHS, and I even opted for MRS.
     Now, I'm not a lover of acronyms. Not since I was a youth and wondered what IRS stood for on the boot-lid of a Triumph car. I was amazed to find that it stood for "Independent Rear Suspension"! It begs the question, does the CL on the back of some Mercedes stand for "Cigarette Lighter"?
     Acronyms are usually used to make something quite mundane sound technical and more interesting.
     So QAS refers to the system that allows you to adjust the BC camband and strap to fit you quickly. Assuming that you bought your BC so that you could have it all to yourself, I'm not sure why it needs to be quick, but with GI diets replacing the Atkins diet as this year's fad, I suppose people's waistlines are going to be all over the place.
     If you're using your BC in conjunction with a thin wetsuit, you may find you need the cushion often supplied to go between you and the backpack. Mares doesn't supply a mere cushion. It's a BPS, or Back Protection System. This is an ergonomically designed set of cushions and they do make the feeling of a tank on your back more acceptable. They also give it the Carrera cockpit look, finished as they are in black and red.
     The Vector 1000 is the only BC in this year's Mares catalogue with SAHS. I needed to make a phone call to find out what that meant - "Self Adjusting Harness System", I was told!
     It's the self-positioning harness developed for improved contouring of the BC to a woman's body. Well, no wonder I didn't know. It provides a couple of rings placed inside the shoulder straps and angled in such a way that "the straps take on the most natural position on the diver's chest ensuring an excellent fit" (I cheated with that last bit and copied it from the Mares publicity material.)
     MRS has nothing to do with going into an NHS hospital for an operation on an in-growing toenail and coming out in a body-bag. That's MRSA. The Mares Release System is used for the integrated-weight pockets, retained by a stud-and-clip arrangement.
     It was one of the first integrated-weight systems to provide a secure method for holding the weight-pockets in place - provided you installed them correctly. It is an optional extra and I heartily recommend paying up. It would be like buying that 3-series BMW without a sunroof, otherwise.

Coping with the weight
So off I went for a trip on mv Tiger Lily in the Red Sea to find out if there were any snags to using the Mares Vector 1000.
     I used it with a single 15 litre aluminium tank and there was more than adequate surface buoyancy to pop me comfortably upright with my mouth well above the water. For those who use twins, it can easily be mated to a Scubapro twin-tank adaptor.
     The significance of the tank was that, combined with the 7mm wetsuit, undersuit and 7mm over-jacket and hood I had to use to combat the effects of chilly January water temperatures, I had to use a great deal of lead. It amounted to a massive 12kg.
     However, the MRS integrated weight-system combined with the trim-weight pockets accommodated all of it securely and without fuss, and I never endured any back-breaking effects caused by the upper buoyancy of the BC pulling against the lower heaviness of the weights. I was always comfortable.
     Just to be sure, I then took the BC to the Caribbean to use it with a small steel cylinder and a skinny 3mm wetsuit. In that case I used less than 5kg of lead but, of course, I was in much closer contact with the BC. Again, I was perfectly comfortable. There was none of that saddlebag effect I have noticed with some other BCs that use integrated weights.
     In both cases, I was able to wear it and forget it. It operated perfectly, dumping air cleanly and without fuss during ascents and giving plenty of surface support. You can dump by pulling either on the corrugated hose or the toggle-equipped dump-valve at the other shoulder.
     During quick head-down descents, the third and lower dump-valve toggle easily came to hand for jettisoning the last remnants of air that might have been present within the buoyancy-cell.
     The zipped pockets were useful, too. Always keen to be a neat diver and not dangle anything over the reef, I stowed my high-pressure gauge away in one pocket, and, horrors on horrors, I stuffed the business-end of my octopus-rig in the other.
     The weight-pouches are quick and easy to re-install securely after pulling them out prior to climbing into a small pick-up boat. And the BC proved easy to unbuckle and slip out of in the water in order to pass it up to the boat driver.
     The Vector 1000 was an unmitigated success. It is the sort of thing you might resist paying the extra for at the time but never regret buying. As for cars, I sometimes wish my wife had a Ford Focus instead of the BMW. It would cost a lot less to repair each time she dragged it down the side of the garage wall.
The Mares Vector 1000 in sizes S, M, L or XL costs £365. MRS weight-pockets are £27.50 extra.

Blandford Sub-Aqua 01923 801572, www.blandfords.co.uk

+ Excellent design + High-quality manufacture

- Do you need to spend so much on a conventional BC?

O2 ANALYSIS ACCESSORY
Vandagraph Quick-Ox
I have already recounted in these pages my conversations with a gas-analysis expert with whom I went diving. He told me that the O2 analyser we were using to check our nitrox mixes was good enough only to distinguish between nitrox and air, rather than accurately display the O2 percentage.
     The problem stemmed from O2 sensors being affected not only by the percentage of oxygen in the sample but also by the pressure and temperature at which it is measured.
     Ideally, one should analyse nitrox at one bar, or atmospheric pressure, and simply cracking open a cylinder valve slightly is not good enough. If you've ever done this, you will also be aware of the cooling effect of depressurised air.
     Many analyser manufacturers have addressed the problem by adding restrictor attachments, including one that uses the diver's own regulator and BC direct-feed hose. Often this adds precious moments to the time it takes to sample the nitrox immediately before diving.
     Vandagraph, the well-known O2 analyser company, has now come up with a solution in the form of a T-shaped accessory that you simply attach to the business end of your O2 sensor. It calls it the Quick-Ox.
     This has a dome-end with an entry hole combined with a concave gas entrance, a chamber where the sensor end sits, and two one-way valves, one either side of it. The idea of the dome and concave gas entrance is to prevent any venturi effect that might suck in some air with the gas sampled.
     First, you wave the analyser cell complete with its diverter in the fresh air to calibrate the analyser unit to 20.9% O2. Then you open the tank valve so that the gas gently flows. Replacing the analyser cell and diverter into the Quick-Ox, you simply place the dome-end over the valve's O-ring or DIN threaded outlet, whichever is applicable. Wait until the highest reading is achieved.
     With the dome-end still held in place, turn off the flow. The gas trapped within the Quick-Ox internal chamber is now at ambient pressure and you will notice that the reading drops a little. This is the true oxygen percentage. It's simple.
     Benefits include not only a true reading but increased sensor life, as it is no longer subject to high gas flows. The flow-rate at the time of measuring is always the same - zero. You have time to observe the reading properly, and there is no temperature-drift effect. There's none of that waiting, often as much as two minutes, as is needed with some flow-restrictors. It can be used with almost any make of analyser.
     Of course, to hold the Quick-Ox in place and turn off the tank valve, you need to place the analyser down somewhere secure. This may need a little consideration on the busy and often crowded aft-deck of a dive boat.
     I used it aboard mv Tiger Lily, and James the dive-guide was so impressed that he forced me to leave it with him. Nitrox-users aboard Tiger Lily will be among the first to benefit from use of the Quick-Ox.
The Quick-Ox costs £17.63.

Vandagraph 01535 634900

+ True readings simply achieved + Longer sensor life

- You may need an extra hand!

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