As with all camera questions, be it on dry land or under water, the best camera is the one that you have with you. If your camera is too big, too difficult to handle, to expensive (so you are afraid to check it in at the airport for example), it’s a bad camera – for you. So please keep that in mind when reading the following. You have to decide for yourself what you are willing to carry around.
In the same aspect, the bigger the camera, the more complex it becomes and the less you can rely on automatic settings. The general rule of thumb is that if you do not know why you cannot get decent photos out of a small, simple camera, chances are that you will struggle even more to master a bigger, complicated one.
Last but not least, this article is about photography, not videography.
When deciding to buy a camera, there are – specially underwater – some general considerations to make. Many of them also apply to dry photography, but underwater has it’s own additional issues that come on top of most of the dry photography topics:
Prices vary greatly and there is no limit on the top. Assuming you buy everything new, the minimum starts at about 350 USD. This investment has to be considered in the context of upgrade ability however. If you need to throw everything you have away and buy all new from scratch once you want to get something better, the overall cost over time might be higher. Higher end models have more variable costs due to the ability to buy not only a camera and a housing, but also different lenses. For certain models you can also chose between plastic and metal housings which considerably drive the price upwards. So you need to decide if you want to start small to try it for the first time and then maybe keep something small & simple, or if you want to make an initial larger investment and build on that overtime. More info on this below.
- Upgrade ability
There are very cheap and easy to use point-and-shoot compact cameras that are however not able to be upgraded at all. You can get an external flash, but the camera is what it is. If you want to get something better, you need to throw the old one away and get a new one. This is the right thing if you either know that you won’t want to invest more into the hobby within the next 5 years or if you have a good use for the old camera when you buy something better. If you want to get the most value out of your investment over a longer time period, I would suggest getting at least something with an interchangeable lens.
- Flood protection
It can – and most likely will – happen to everyone: You do something wrong and your camera lets water in during a dive. Or you simply use your equipment long enough until something fails. Not all cameras can be serviced in a way to 100% exclude eventual material fatigue. While flooding is not necessarily the end of your camera, there are some models where the chances that the camera will survive are basically zero, and others where your investment is much better protected. A simple waterproof point-and-shoot for example has a lid for a battery cover. If that as a sand grain, a salt crystal or a hair on it, water will enter the lid and will be immediately inside the camera beyond your reach, on the electric parts. If you have a case around your camera, a single drop will be first inside the case, on the camera surface, and you need to have much more water in the case to affect the camera at all. It can happen that a leaking case might only let water in while you are between 1-5 meter depth, since further down the pressure is high enough to push the lid shut so hard that no more water enters. In other cases, the case will leak only at greater depth. It all depends on the reason and location of the weak spot.
The simpler the camera, the less control you have over the resulting picture. That might be fine when you start off, since you might not know a lot about aperture, ISO and shutter speed, but when you are trying to achieve a certain effect or are unhappy with the way your photos look like, you need to be able to use manual settings in order to affect the result. If your camera does not give you full manual settings, even buying an external flash might not improve your pictures a lot since the camera will not allow you to change settings to make full use of the additional light. If you want full control, you should have a camera that has a “M” setting, or at least a “S” and “A” mode (Speed and Aperture priority). Further, RAW image capability will significantly improve your colors under water. However, as described in the introduction, more controls are only good if you know what you are doing. If you do not know how changing all the dials on your camera impact the photo, you will either use the wrong settings or simply use the automatic modes, in which case the result will be the same for a small compact as for a big DSLR.
A better camera will make it easier for you to shoot different type of photos – at ever increasing cost however. A small camera for example might allow you a bit of zoom and wide angle as well as a simple macro mode. A medium sized camera will allow you to insert 3-4 different lenses into the case and attach different “wet” attachments outside for wide angle or macro. A big DSLR will allow you to attach a dozen different lenses to the camera but you will have to buy different domes (exchangeable fronts to accommodate different lenses) to fit them. The lenses will be much more expensive and the domes as well however. Changing the lenses however is only possible on dry land, so if you go with a macro setup into the water, you are stuck with it for the rest of the dive.
The biggest quality improvements that you get with a better camera are faster auto focus and reaction time (very important for fast moving fish), low light capabilities (important for things that are too far away to be affected by a flash) and of course resolution (if you want to print photos larger than a A4/letter format.
- Size / Weight
Referring back to the disclaimer above, the best camera is the one you have with you. The size and weight of underwater equipment can expand dramatically with the decisions you make. Sizes vary from compact, waterproof point-and-shoot cameras that will fit into your pocket, over well equipped interchangeable lens setup with strobes that fits into a carry-on luggage up to large DSLR with many lenses and their enclosures that require a full-sized luggage. So consider that you will also need to invest into transportation equipment, carry the camera around on dry land and require space in your dive resort to service it. Also, larger cameras have considerably more maintenance requirements, more things that can break, batteries to charge etc etc.
What you want to shoot? While cheap cameras offer some zoom, wide angle and macro modes, the capabilities of those are quite limited. If you invest into a better camera, you can attach different accessories for different types of photo. Those include different lenses, diopters, flashes and more. Be aware that if you buy a fish-eye lens for a DSLR you also need a fish-eye dome/lens cover for your underwater case. Medium price cameras have wet attachments to change while under water, but if you want to use more professional equipment you will have to make the decision before the dive. Further, if you want to take photos of fast moving things, a good auto-focus and a fast response of the camera can be all that prevents you from taking a decent photo. Cheaper cameras will take considerable time between pushing the shutter button and the actual photo.
It’s dark underwater. Very dark. Unless you shoot in snorkel-depth during a sunny day, you will need additional light, unless you are fine with a picture that has only one shade of green or blue and no other additional color. But even then will still get only a blurry, very dark image in depth below 15 meters. So you will very soon need to use a flash. Since light does not carry very far (see the inverse-square law which applies to light), a small, internal flash on a compact camera will not help you to change the light situation on anything more than 50cm away from you. Actually, a small strobe directed at something far away will make the image only worse since you will illuminate all the plankton between you and the object and create so-called back-scatter (imagine shining a light into fog that makes you see more of the fog but not what’s behind it). So the further away an object is, the better your light setup will have to be. Same goes if you go deeper, since it’s darker down there.