Dive Photos: Compact or Full Frame?

It seemed only yesterday that I did a side-by-side comparison test of a really good digital single-lens reflex (DSLR) camera against a similar quality film camera for a British magazine and found that the results from the film were so much better. Times change.

Of course there will always be advocates for using film, whatever advances are made on the digital front. One Internet pundit reckons a frame of Fuji Velvia transparency film is equivalent to a 175MB digital file, whereas I can rarely get a native raw-image camera file with more information than maybe 12MB. I can’t confirm he is right but I can say that since the time of my original test, digital cameras have progressed to the point that few people now shoot film underwater. The fact of the matter is that digital image gathering has made photography very easy, and easy is what is needed when you are underwater, short of time and with a mind befuddled by breathing gases under pressure.

The ability to shoot raw image files is essential for top-quality pictures because it allows you to make so many photographic decisions on your computer long after you took the picture. That way, you can concentrate on focus, composition and grabbing the moment. High-quality results suitable for reproduction in print are then assured.

I’ve been using good quality digital cameras for a few years now. I started with a Fuji S2 Pro DSLR and progressed to a Nikon D200, simply for the bigger viewfinder and LCD monitor. Both cameras give excellent results that have been reproduced in endless calendars, books and double-page magazine spreads. So I admit that today’s DSLRs are up to the job that maybe the first ones were not.

Spending a lot of time in the company of other divers, I get to see what they are using. Many amateur divers use compacts. I was seduced by a little Canon G9 compact (now there’s a G11) and bought one. I had visions of myself checking in at airline counters with my underwater camera in my pocket rather than facing the long arguments about the weight of my DSLR kit. I had visions of swapping seamlessly from wide-angle to macro during a dive, which you can do with a compact digital camera. Though it is a compact, the G9 is a proper camera with a good lens that has full manual controls and can shoot raw files without a very long delay while it writes them.

DSLR cameras use a buffer to allow almost continual shooting, whereas most compacts make you wait to take the next shot while the process of recording takes place. In the meantime, you miss the next shooting opportunity. The bigger the file, the longer this takes. Raw files record virtually everything picked up by the camera’s image-gathering sensor and with the right software on your computer, you can make a lot of the decisions about technique after the event. The sky’s the limit. That suits the under-pressure underwater photographer.

The Canon G9 produces pictures of remarkably high quality. If such a compact had been available when I went over to digital photography, I might well have started with a camera like the Canon G9. It is only spoiled by the typical time lag between pressing the shutter release and getting the picture.

Have you noticed that modern-day compact shooters on land now employ the techniques worthy of Victorian photographers when they take pictures of their friends? Hold it! Then the picture is taken. The spontaneity has gone out of it. I tried taking candid pictures of my kids on a beach but was left with lots of shots of patches of sand where they had been when I pressed the button. This is a problem with all compacts because they need to stop writing to the LCD viewfinder and write to the memory card. It virtually disqualifies it as a camera for photographing fastmoving subjects like fishes. I might have got used to it if I’d persevered but I just got shots of the vacant places where fishes had been when I pressed the button. I still use the G9 for certain surface shots. Hold it! Otherwise, compacts are really good for static subjects and personal snaps only.

You will probably expect me to start talking about megapixels. This is marketing hype manufacturers use to protest that their cameras are better than the competition. It was relevant not so long ago, when a one-megapixel camera was really something. My Canon G9 employs more megapixels than any other camera I use but that doesn’t mean it takes higher-quality pictures. My Nikon D200 takes better quality pictures than the G9, and that’s considering optical performance, pixilation, digital noise or grain and dynamic range. How come? The compact has a tiny little sensor the size of your pinky nail that it crams all the information out of, resulting in a great deal of digital noise or grain if anything higher than the lowest ISO (light sensitivity) setting is used.

The Nikon D200 is a DX (Digital Index) camera. It has a sensor around the size of an APS-size piece of film. When I first went over to digital image gathering, I used a Fuji S2 Pro, also a DX camera. Because the frame is smaller than a regular 35mm frame of film, I found that I needed DX-rated wide-angle lenses when I first went digital. This is because a 50mm lens on a DX camera has the same angle-of-view as a 75mm lens on a full-frame film camera. This meant added expense. However, DX cameras can use lenses of the highest optical performance, and digital noise is far less of a problem than with a compact unless you need ISO settings higher than, say, ISO400.

I still use DX cameras with their DX-rated wide-angle lenses, and am very happy with the results. Yet, finding myself in the company of other underwater photographers, I started feeling avaricious towards those who used FX (another way of saying full-frame) digital cameras that had a sensor the size of a full frame of film. What were they getting that I was missing? I bit the bullet, raided my retirement fund and splashed out on a Nikon D700 FX camera with a housing to suit.

What did I achieve? Firstly, I need a full-frame fish-eye lens to get the same angle-of-view that I was used to. Fullframe gives a shallower depth-of-field but that was no problem because I simply up-rated the ISO to get the smaller lens opening needed for the same effect.

With DX, I normally use ISO100, whereas with FX, I use ISO400. One thing the full-frame camera allows you to do is increase the ISO to amazingly high light sensitivities, such as ISO4000, without the picture becoming affected by digital noise or grain, and ISO1000 is 10 times more light-sensitive than ISO100. Noise is caused by electrical interference between the pick-ups on the sensor, and it is more apparent when lots of pick-ups are crammed together in a small space. An FX sensor is many times bigger than that of a compact camera and so for the same number of megapixels, it will produce less noise. This means the light-sensitivity levels can be jacked up without grain. You can set an FX camera at ISO 6400 without too much ill effect. Even higher ISO settings are available.

Because of this, I had the delusion that I would be able to dispense with my underwater flashguns and use these very high ISO settings. Conditions underwater are not just about low light levels, though. The color of the light is affected and if I wanted anything more than monochromatic pictures at depth, I found I needed to take some white light (in the form of an underwater flash) with me. Not only that but natural light is always flat and from above, and is not very interesting. I had to dispense with one of my photography skills, that is, the ability to light something in an interesting way.

So I was back to the use of flashguns, or strobe lights, with my FX camera just as I do with the DX setup. For example, I use ISO400. I now have two underwater camera setups that I use in tandem. One uses an APS-size frame (DX) and the other full-frame (FX). The quality, for the majority of underwater shots, is indistinguishable. The FX camera is fantastic in low light conditions, however, with light sensitivity settings like ISO6400. That’s 640 times more light-sensitive than ISO100. It really comes into its own when photographing my kid’s school play. It’s just a pity it costs so much!

John Bantin is the technical editor of DIVER magazine in the United Kingdom. For 20 years, he has used and received virtually every piece of equipment available in the U.K. and the U.S., and makes around 300 dives per year for that purpose. He is also a professional underwater photographer.