By jeremai, in Aquarium Photography,
Most of this primer is written for DSLR and advanced point and shoot (P&S) users. If you use a basic P&S, keep in mind that a firm grasp of the following concepts will improve photography from even the most automated of cameras.
First and foremost, READ YOUR MANUAL (cameras, lenses, and all other equipment you’ll be using). You cannot possibly hope to take great photos if you do not understand the features available to you. Also, understand the basics of your camera’s settings and how they interact with each other. Here’s a quick rundown of the basics:
The shutter speed is kind of the stopwatch of the camera. It sets how long the camera stays open. On most cameras, all the shutter speed numbers indicate fractions of a second; that is, the setting “500” means the camera will stay open for 1/500th of a second. Commonly available shutter speeds are 1000, 500, 250, 125, 60, 30, 15, 8, 4, 2, 1 and “B”. Note that each speed is half or twice as much as the speed next to it. 1000 lets in the least amount of light (camera is open for a very short time) and is called a “fast” speed, while 1 lets in the most amount of light (camera is open for a relatively long time) and is called a “slow” speed.
What shutter speed you choose can have a big impact on your photos. If you’re taking pictures of things that move like active fish, you can decide to “freeze the action” and shoot at 1000. This will stop all but the very fastest fin twitch. On the other hand, somea little blur can help to convey a sense of movement, like in a swaying coral. Experience and practice will help you decide what you’re trying to do, and which shutter speed you should use. When in doubt, try the same photo a few different ways. Taking notes helps you learn, too.
The aperture is like the pupil in your eye. It’s a mechanical “iris” inside of the lens that opens and closes to varying degrees to control the amount of light that passes through the lens. When an aperture is “wide open”, it’s gathering all the light the lens is capable of. When the aperture is “stopped down”, or closed down to a pin-hole, it’s letting pass the smallest amount of light possible. This is just like your eye: in a dark room, your pupil opens wide to gather light; in bright daylight, your pupil closes down to cut back on the amount of light entering your eye.
In addition to controlling the amount of light that passes through the lens, the aperture controls something called “depth of field”. In technical terms, depth of field is the expansion of the plane of focus into a zone of acceptable sharpness. A wide open aperture like f/2.8 has very narrow depth of field, while a “slow” aperture like f/22 has very broad depth of field.
Take a look at the photo of the Fungia sp to the right. Notice how only part of the coral is in sharp focus? Selecting a large aperture (small number) lets you choose what part of the photo you want the audience to focus in on by isolating it and blurring the background or foreground. The best way to ensure the correct exposure is to set your camera to Aperture Priority mode. This will let you choose the aperture setting you want, and the camera will automatically select a shutter speed for you. This takes half the guesswork out of the equation and lets you focus on the other aspects of getting a good shot.
The “correct” exposure for a given scene is a function of at least 3 things: shutter speed, aperture and film speed. A basic rule of thumb is to start with a given aperture, say f16, and choose the shutter speed closest to the ISO setting of the camera. Once you have this basic starting point, you can adjust the shutter speed or aperture for effect and modify the settings to get a good exposure.
All exposure meters, including the one in your camera, are basically stupid. They’re calibrated against some standard, and if your photos aren’t standard, then they might tell you the wrong exposure. Let’s say you want to photograph a coral under metal halide lighting. If you point the camera at the top of the coral where it gets the most light, the camera will adjust the exposure for that reading the the parts of the coral in shadow will be rendered an unrecognizable black. In contrast, if you direct the camera at the shaded parts of the coral, the camera will expose correctly for the shadows and the brighter parts of your image will ‘blow out’ to a flat white. You, as a photographer, are charged with getting around this by composing a tighter shot with less contrast, or by adjusting your angle (or the coral’s angle) to the light. Experiment!
Ok, so that was a lot to digest. Here’s a quick run-down of the most basic tips, plus a few specifically designed to get great aquarium shots:
Turn off all pumps and powerheads that provide water movement in your tank. Put your camera on a tripod or other sturdy support. Clean your tank, inside and out. Shoot parallel to the front glass (point the camera perfectly straight into the tank). Shooting at an angle will cause distortions. Settings
Shoot at the highest, finest, largest setting possible. For P&S cameras, that means the largest JPG set to Fine. For DSLRs and advanced P&S cameras, shoot in RAW. Start with auto white balance, it will often yield acceptable results. When you gain skill (and if your camera is capable) you can use a custom white balance setting. Shoot on the lowest ISO setting available on your camera. Turn off your flash, as all it will do is create a flat, dimensionless, yellow-tinged photo. Use either a remote shutter release or your camera’s timer function when taking photos. This will help to eliminate camera shake caused by pressing the shutter button. Post-processing
Most images will need some adjustment after you take the photo. This can include contrast, brightness, sharpening, color saturation and white balance adjustments, as well as other more advanced adjustments. The basics can be done with the software included with your camera or a program like Google’s Picasa; the more advanced adjustments will require a more advanced program like Adobe Lightroom, Photoshop, Pixelmator, or GIMP.
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