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DSLR
Buying Your First Underwater Digital SLR Housing
By Steve Warren
Buying your first underwater digital SLR system can be daunting. Any system will be costly and it's likely that the trips you'll use it on will represent valuable holiday time and will themselves be expensive. This article is an introduction to some of the features and benefits of underwater camera housings. It isn't specific to any brand. It's designed as a primer to give you a little information to get started with.
The Housing Manufacturer
Most housing manufacturers are small companies employing just a handful of people. Usually the owner is an engineer who began by building a housing for a camera to use himself. He might have done this because he's been in the game so long that when he started you simply could not buy a housing in his country. So he created his own from necessity. Or it could have been there wasn't a housing on offer for a camera he especially wanted to use. Other times it is a case that the underwater photographer simply didn't like the ergonomics of what was available and designed a housing to better meet his own preferences. Often friends see the housing and ask him to build them one too. From there it is a small step to forming a company and going into manufacturing and marketing.
Certainly among housing designers you'll see very personalised designs for the same camera. As we'll underscore later, it's essential to go and take a good hard look at housings for your camera before you purchase. You need to try and find a housing design that is closest to your own aspirations.
It's doubtful that any housing line is produced "in house". The housing designer will be dependent upon other companies to mould, cast or carve out the hull, provide the control shafts, make the O ring seals, supply flash circuits and craft the optics for the ports. The housing designer obviously does do the actual designing, but after carefully choosing his subcontractors for the manufacturing of all the components, usually onlydoes the final assembly and quality control checks.
With so many other companies involved in the production of an underwater housing, it's not uncommon for delays in supply to occur. So don't be surprised if you have to wait to take delivery of your housing. It's wise to anticipate that several months might pass by before new designs are available off the shelf. So plan your purchase well in advance of when you will really need your system.
Annoyingly, camera manufacturers rarely cooperate with housing manufacturers. This leads to the situation that the designer cannot get to work on creating a housing for a new camera until he can buy one himself. In part, this is what leads to an initial strong demand for housings for a new camera. The camera manufacturer may announce a new model long before it is actually available. Some underwater photographers actually start chasing down housings from that point onwards and get onto the waiting lists for the first units. This is especially true of the best thought of aluminium models.
Acrylic or Aluminium?
Acrylic is usually only used today for custom built housings or commercially produced housings that are being built specifically to keep purchase costs low or where concerns exist over how many units will be sold.
A few underwater photographers prefer to design and build their own housings. The usual reasons are to produce a housing for a camera that isn't supported by a mainstream manufacturer or to have features that aren't available off the shelf. It's much easier and cheaper to work with acrylic for one off projects than to build from aluminium.
Commercial housing producers of acrylic cases are normally driven by three goals. To get prices down, get a housing out fast and reduce their risk of getting caught with dead stock.
There's no question housings are expensive, with the best costing thousands of pounds by the time they are ready to go in the water. Acrylic housings are much less expensive to make than aluminium models and these savings can be passed on to the client. Acrylic housing manufacturers will often also reduce their costs by using several basic box designs that can fit most camera bodies with a few minor adaptations. By avoiding tailoring a completely new housing hull to the contours of a specific camera model they can cut costs. Using box designs also means that they can get a housing onto the market very quickly after a new camera is launched. This often gives an acrylic manufacturer a significant head start over aluminium competitors who usually have to design a new housing from scratch as each new camera model is introduced. It also reduces their risk of getting caught with dead stock. They can hold a large quantity of boxes and then produce very small runs of housings that they've added controls and camera mounts to for specific camera models. The economics stand up for the manufacturer who can use his stock of boxes over a long period for many different cameras.
Finally, the one size fits all approach means that acrylic housing manufacturers can accommodate a much wider choice of cameras than aluminium manufacturers. This can be important if you wish to use a camera model that a housing does not exist for as an acrylic manufacturer may be able to adapt a box housing to fit it.
Because acrylic housings are usually offered to save the customer money, there are some disadvantages to be expected in taking the price driven approach. The box design tends to lead to an oversized housing. This obviously makes the housing bulkier in the water, creating more drag when swimming or shooting in current. It also makes the housing less easy to travel with. Less well known is the weight penalty inherent in most acrylic SLR housing designs. The larger size of acrylic cases compared to aluminium models and the need to be operable to, say, 60 metres, meansthat the acrylic housing must use much thicker walls than a comparable alloy hull. The large internal air space of many acrylic cases also requires them to be ballasted if they are going to be used under the water. This can create a housing weighing in at as much as 5kg – roughly twice the weight of an aluminium housing for the identical camera. This has implications for air travel as many carriers enforce a 5kg limit on hand luggage. Remember this is just the weight of the housing. It doesn't include a port.
Using a box design also tends to limit your options for control placement. All housings - acrylic and aluminium - are a compromise. The camera they protect will have been developed to provide the best possible handling characteristics - on land.. When you enclose it inside an underwater case it's a real challenge to the housing designer to reconfigure the controls to retain the ease of use of the camera. He has to contend with the size of the hull and the fact the user may be using thick gloves or be nearly numb with cold. Digital SLR's are much harder to design around than film cameras as they have so many more controls. Because the cameras are no larger than film models, the controls are packed into a very small area. Accessing these easily through a housing depends upon the talents of a highly skilled and experienced designer. Each time you use your housing that designers strengths and weaknesses will be working for and against you.
The philosophies behind aluminium housing design are usually very different. Aluminium housings are normally produced to fit a specific camera model. This allows the designer to keep the housing as small as possible leading to the term "glove housing". Because alloy is strong and the internal volume of the housing is low, the housing can be lightweightyet still resist the pressure encountered on deep dives. An alloy housing for most popular digital SLRs will usually weigh in at between 2 and 2.5 kgs. The housing and camera will normally be just slightly negative and so does not need any ballast.
Producing aluminium housings is much more expensive than making acrylic cases. Production costs, either through casting or by using C and C machines, are higher than working with moulding processes used to produce most box cases. Building a housing for a specific camera means that volume production is out of the question. For one professional level digital SLR camera a top European housing manufacturer produced just twelve cases for worldwide sales. All of their research and development costs had to be recovered from their sales of those dozen units. Even for best selling digital SLRs whose terrestrial sales are measured in ten of thousands of units, aluminium housing sales may run, internationally, to only a hundred units or so.
The designers of aluminium housings know that they are not competing in a wholly price driven market. Their clients are more likely to be looking beyond short term cost savings and willing to pay more for a housing they
believe will perform better in the longer term. This has led to fierce competition to produce innovative and user friendly housings that can attract underwater photographers based upon ease of use, reliability and versatility. Currently, worldwide, there seems to be a wider selection of aluminium housings on offer than acrylic models.
Occasionally a housing manufacturer will hedge their bets and produce acrylic and aluminium housings. This enables them to make sales in both the price and performance driven markets.
Ergonomics
How your housing handles in the water is crucial to quality and rewarding underwater photography. A major attraction of choosing to house a digital SLR is to overcome the problem of the delay between tripping the shutter release on a consumer camera and it taking a picture. This makes D –SLRs the first choice for fast moving subjects. But the shutter release isn't the only control you'll need to use. To control light you'll need access to aperture and shutter speed. To compose your image you may want to zoom in or out. A poorly designed housing can make key controls hard to operate and slow you down, negating some of the benefits of using an SLR. The art of a good housing designer is to prioritise which controls are most important and place these at your fingertips. This ensures you can operate vital camera functions with the housing at your eye while tracking a subject that is on the move.
Ergonomics are a very personal thing, both for the housing designer and the housing owner. Control placement is one of the main differences between different housings made for the same camera. Another is the design of hand grips. Grips have become standard issue on digital SLR housings. Older housings for small film cameras did not always use grips.But as controls started to appear on camera backs the housings got a little deeper and it became difficult to hold housings comfortably unless grips were fitted. To allow for different hand sizes and the reach of your fingers, some housings have grips that can use spacers to adjust for the most comfortable fit. Others have a left grip than can be moved forward to help counterbalance long lenses and place your fingers alongside the manual focus gear built into some macro ports. It's important to test their functionality with your camera in your short listed housings to get a feel for which you prefer.
Viewfinders
Unlike consumer digital cameras, digital SLR's don't let you use the LCD monitor on the back for shooting. The screen is only used for replaying your image. So it is essential that you can clearly see your subject through the cameras own reflex viewfinder. The viewfinder is obviously then at the heart of an effective underwater single lens reflex system. And yet this is one of the most misrepresented features by housing manufacturers and retailers and subsequently one of the most misunderstood areas by purchasers.
Your camera designer assumed you'd have your eye right up against the viewfinder window. When you add a housing you have your eye forced further back by the depth of the hull. Your face mask forces you further back still. To appreciate the significance of this simply put your mask on and look through your camera. Forcing your eye back by just a few millimetres makes it very difficult to see the entire viewfinder at once.
In the past the preferred cameras for use in housings had special oversized viewfinders called action or speed finders. Designed for photographers using dive masks, protective goggles or visors, only a handful of cameras accepted these finders. All were professional models and priced accordingly.
In the late eighties Nikon introduced cameras with built in viewfinders that were designed specifically for people who wore glasses. These compact user friendly high end amateur cameras created a revolution in underwater photography at the time. Finally providing excellent view-finding when housed at a comparatively low price (the entire camera cost less than an action or speed finder alone), underwater photographers switched to SLR cameras in droves.
Unfortunately most digital SLR's have viewfinders that are a throwback to the bad old days. They have small eyepieces. To be able to see the whole of your viewfinder through your housing and mask, it is necessary to fit a special viewfinder optic. This is where misinformation and confusion over a vital aspect of housing design reigns. Most housing manufacturers fit image reduction optics to their cases. Image reduction finders effectively place your viewfinder screen further forward so that you can see the entire frame and the information displays edging it. The problem is it also makes your viewfinder 15 to 25 percent smaller. This can impair composing your image and make it difficult to read important information such as exposure readouts. If your housing has the facility to focus manually the smaller viewfinder image is a definite hindrance. It becomes hard to see when the subject is critically sharp. When choosing your housing it is important that you try your camera in the housing while wearing a mask. You can then assess whether the viewfinder image is acceptable.To make matters worse some housing manufacturers imply that their optics actually magnify the image. It's not until you get into the small print that the truth comes out.
Genuine viewfinder magnifiers are rare. They are complicated and expensive to produce. Unlike the simple optical formula of most reducers, magnifiers use a combination of lenses and prisms to provide an image that remains bright, the right way around and the right way up. A well designed magnifier significantly enlarges your viewfinder and is a very practical and desirable feature. With one you can clearly see your subject, read your displays and manually focus your lenses with ease.
Strobe Connections
See Buyer Beware - Digital SLR's and Strobes.
Digital SLR cameras usually require specially dedicated strobes for TTL automation. Development of underwater strobes that work on TTL with digital SLRs and adaptation circuitry to "trick" strobes designed for film cameras to operate with digital SLRs continues. However some manufacturers have hit snags. It isn't helped by camera manufacturers regularly changing their flash technology so that even their own strobes may not be compatible with their next camera model.
Camera housings most commonly offer a Nikonos type flash connector. This has become established as an industry standard since the Nikonos V TTL system was launched in 1984. However even this connector varies between housing brands and even the same housing models! The reason is that most digital SLR cameras cannot operate properly if they detect TTL and ready light information from a non dedicated strobe. To prevent the camera recognising an incompatible strobe, the TTL and ready light connections are not connected. The strobe will fire, but the flash exposure must be controlled manually by the photographer.
Not all camera housing manufacturers produce matched housings for dedicated land flashguns. They hope you will purchase an underwater gun that they also produce to go with their housing. So they do not offer the option of connecting a dedicated TTL strobe inside a housing. However it may be possible for your dealer to install the necessary connections as a custom feature. This should be clarified before you purchase your housing.
Some camera housing manufacturers do provide housings for land flashguns designed for TTL use with digital SLRs. These camera housings will have all the circuits connected. This means you can use TTL just as you do on land. But because the housing manufacturer won't know if you will use a housed strobe or if you might prefer to use an underwater strobe, the Ttl and ready light connections can usually be disconnected. This lets the photographer use pretty much any flash unit. This can be useful if you use more than one type of strobe - perhaps a compact gun for macro work and a larger gun for wide angle photography.
The Nikonos V connector accepts by far the widest selection of strobe systems on the market. So it's usually your best choice. If your housing also offers the option of switching between TTL and manual guns, then you have covered yourself for every strobe possibility.
Another connector developed by Subtronic is popular with European housing manufacturers. An extra contact can carry additional information needed to operate some TTL systems such as Canon digital strobes in housings. The S6 connector is exceptionally reliable and highly regarded. Unfortunately, it has not been adopted internationally by either SLR housing manufacturers or underwater strobe designers.
Some housing manufacturers offer their own unique flash connectors. They expect you to purchase both your camera housing and your strobe from them. The main disadvantage to non Nikonos type connectors is that if you do not have a back up strobe system you may find it very hard to borrow or hire a compatible strobe if yours stops working.
Ports
The digital SLR cameras used underwater accept a range of lenses and lens accessories to ensure the camera is versatile enough to handle a wide range of subjects. Without this selection your choice of subjects would be hampered and your creativity restricted. Underwater photographers tend to work at extremes and have to use lenses to suit. Fisheye lenses are the usual choice for wreck and reef vistas and for working with large animals including sharks and whales. Macro lenses are used to photograph small subjects like fish right down to the tiniest detail in a cup coral. It's not at all unusual for an underwater photographer to eventually own four or five lenses to cover all the subjects they want to work with. A thought out camera housing will have a port system that's adaptable to your lens needs now and in the future as your requirements may well change. It needs not only to accommodate "standard" lenses but ideally accessories such as close up lenses, teleconverters and, possibly, extension tubes.
The ports used on digital SLR housings will either be flat or dome ports. Flat ports perform best when used with macro lenses or lenses having a widest angle of, roughly, 70 degrees. The ports are manufactured in a range of lengths to accept different lenses. Because macro lenses extend quite a lot as they are focused between infinity and their minimum focusing point, these ports tend to be quite long. Air in the port tends to help offset the natural tendency of heavier lenses to pitch the housing forward. You can also cup your hand under the port for extra support if you prefer. Some manufactures give you a choice of a port that really only works in autofocus or special ports that incorporate controls to allow you to choose between auto and manual focus during the dive. Manual focus can save the day if your autofocus cannot "lock on". This can be a problem with certain subjects and in poor light, or when using teleconverters. Some photographers also find that the vibration from autofocus motors can spook shy animals and find manually focusing their lenses makes the subject easier to work with. The design of some camera lenses may mean this benefit is unavailable due to the position of auto/manual focus switches.
Extension rings for your housing are a useful option. These can be used to lengthen a port you already own so that it can be used with a longer lens. A typical use might be to adapt a port used with a standard macro lens of 50 or 60mm focal length to work with a tele macro like a 100mm or 105mm. They are also used to let you add in a teleconverter or, occasionally, extension tubes. Extension rings come in a range of lengths to let you customise your rig as needed and save you money, weight and bulk when compared to buying a new dedicated port. Most, but not all, housing manufacturers offer extension rings.
Some flat ports are designed to take accessories. For high mag photography some ports have space to take a close up lens inside. Others accept wet lenses on the front that do the same thing, but allow you to choose when to use it as the lens is removable during the dive.
Dome ports are usually chosen for lenses wider than 80 degrees. Domes provide important benefits with wide angle lenses. Their design ensures that the angle of the lens does not change significantly when you use them underwater. A flat port behaves like a mask and makes everything appear nearer and larger. So it defeats the purpose of using a wide angle. With a good dome port you can shoot a half and half shot of a person and their body won't change size as it passes through the waterline. Try this with a flat port and it's just like looking at your thumb through a glass of water, and quite unflattering.It's generally accepted that physically larger domes yield sharper images than small domes, at least with very wide angle lenses.
A concern with wide angles behind domes is that flare can become a problem. It's easy for stray light to bounce around the dome and mar your images. To help avoid this most dome ports either incorporate a shade or can have one fitted as an option. Along with helping to defeat flare, the shade also helps protect the dome itself from scratches, not just during your dive, but also from the rough and tumble of transporting it and the bunfight of some camera dip tanks.
A few housings cannot accept fisheye lenses. The bulk of the housing means that the fisheye lens is mounted to far back and will photograph the inside of the housing. It's worth checking this if you expect to use fisheye lenses as it will be very expensive to change your entire housing system later on.
Extension rings are often used in combination with dome ports to enable the use of larger zoom lenses. Often one extension ring will suffice for adapting both a standard macro port for use with a telephoto macro lens and for extending a port developed for fisheye photography to work with a wide angle zoom.
Ports may be made out of acrylic or glass. Optically there is little to choose between them when new. Acrylic tends to hold static and attract dust. So they can require more cleaning which, in turn, can degrade them over time. They are also very easy to scratch. On the plus side they are cheap to manufacture and light scratches are simple to polish out. Glass is usually used by high end housing manufacturers. It costs more and can be heavier, but it is harder wearing. They don't create static and require less cleaning as a result. Glass ports are sometimes coated to reduce flare, much as a normal camera lens is.
Port systems, particularly domes, can seem expensive at first glance. However they are ultimately the final optic between your very expensive multi megapixel camera, professional level lens and a subject that may have cost you thousands of pounds to find. Dome ports especially are lenses in their own right and a good one is an investment.
A final warning about lenses. Some photographers have been confused by the change from the 35mm format to the digital chip and it's effect on lenses. Just because a digital camera can accept a lens designed for a 35mm camera does not mean that lens is also compatible with your needs as an underwater photographer. The smaller chip size used on almost all digital SLRs compared to a 35mm film frame means that in effect you have a built in teleconverter. Most macro photographers consider this an advantage. It allows for greater magnification of small subjects. But for wide angle photography it is a very real drawback. For more information please see ???
Pre Sales And Back Up
It's easy to get seduced by the kit. But it's only a component. The useris another part of the equation. And so is the dealer, a point that is all too often overlooked. A good dealer will be able to talk through the interrelationships between the subjects you want to capture and the equipment you'll need to use to do it. They'll also provide essential back up including routine servicing and repairs. So just as you need to take care to choose your housing, you also need to be careful in selecting your dealer.
In the UK most underwater camera specialists have exclusive rights on the housing lines they offer. Once you purchase your housing you'll be tied in to them for future advice and purchases as well as aftersales. So it makes a lot of sense to ask around to see if they come recommended, especially when problems arise (everyone can be a truly great dealer when everything is working...). It's also good practice to visit their showroom and meet the staff to get a sense of whether these are people who you want to do business with.
Good luck with choosing your first rig.