In this guide we will attempt to outline some basics of taking photographs and/or videos, using different techniques that are available, how to focus on getting that specific look/vibe you want to capture, and some important things to remember when photographing through glass or when working with a scene that has distinct highlights and shadows. This can be highly beneficial in order for you to capture good looking images to be used for your tank journals, or to be able to share across what the tank looks like in actual lighting.
How to Get the Exposure Right
You’ll need to keep an eye on exposure settings so you can avoid underexposure. The light is weak, and your options for shutter speed and aperture are limited, so you’ll be pushing up towards a very high ISO. That’s because it’s better to suffer a little noise than a blurry picture.
Using either full manual mode or shutter priority on your camera. Your exposure time will depend on how quickly the fish, etc. is moving. For creatures that move slowly, a time between 1/25 and 1/80 will usually do. For quickly swimming fish, you need to shorten it to the range from 1/100 to 1/250, or sometimes even shorter.
Handling That Low Depth of Field
The lack of light limits your choice of aperture. Aquariums are usually lighted for viewing with your eyes, not your camera. Even with the high ISO and long exposures I’m recommending, you’ll end up using an aperture from f/2.8 to f/5.6, and that means a low depth of field. You’ll have to work with that creatively. You’ll need to choose precisely what will and won’t be sharp in your photos.
When photographing a fish at a low depth of field, the fish’s orientation relative to the lens also plays a role. For example if the fish is facing the lens, then only its head will be sharp. It’s best to photograph a fish from the side; then all of it will be sharp.
For slow creatures such as these beautiful snails, use a longer exposure and set the aperture to f/8 and get more depth of field; in macro photography, this is important.
What About the Reflections?
Another frequent complication in aquarium photography is that aquarium glass reflects nearly everything around it, filling photos with unwanted reflections of the photographer, passersby, and everything shiny in the room. This problem, too, has a simple solution - an anti-reflection shield. Either buy one of these special rubber lens shields, or make a tube out of black cardboard or hard fabric and place it over the lens. Press the edge of the anti-reflection shield up against the glass of the aquarium to shield away reflections.
Using a shield has one disadvantage: with the lens up against the aquarium glass like this, you can’t focus on objects that are right next to it. But this is a fair trade for a reflection-free photo.
The last stumbling block is that you’re working with multiple optical environments - air, glass, and water. Light rays are refracted at various angles at the boundaries between each of these environments. This can cause distortion and optical defects. To suppress these negative effects, you have to always hold the lens perpendicular to the glass and to the object in the aquarium. Otherwise the photo will not be sharp due to light refraction, and chromatic aberration (a blue-violet aura) will appear around objects.
What if the Aquarium Glass Is Damaged or Dirty?
Aquarium glass isn’t always clean, and you need to take that into account. Ideally you should always take a cloth and some cleaner with you to clean dirty glass. With their help, you can often even clean away fingerprints. You might get some funny looks, but it’s worth it for a perfect photo.
But the glass may also be scratched, or seaweed may be growing on it from the inside, and sometimes you can’t influence that. Here the solution is to not focus on things that are right up against the glass. If you’re focusing about halfway into the aquarium, then the defects in the glass won’t be within your depth of field, and so they won’t be visible.
