As a child one of the first pieces of advice I got regarding shooting through glass was "You absolutely cannot use a flash to shoot through glass." That was probably oversimplified for my six or seven year old self at the time, but the fact does remain, it's hard to get a good shot through glass.
So of course it figures that some of the most colorful animals in the world are fish and various invertebrates that live underwater.
|Who said plaid went out in the '70s?|
|If Key West could design its own fish|
Or this guy. Who looks like the result of letting an eight-year-old little girl color in the fish. Dotted lines? In aqua and bright yellow? (And I have to love that the ring around the eye is also aqua and yellow - though you may have to enlarge the shot to see that. It makes the false eye on the tail even more awesome.)
Now, if you look at these shots, you can see that it is possible to get good shots through glass. I wasn't jumping in their aquariums with my Canon or anything!
The first thing you have to establish is whether or not flash photography is allowed. Most public aquariums are no flash zones. This is for the health and safety of the animals, not to mention the people you're going to blind if you keep firing that thing. Many aquatic life-forms prefer dark environments to help them avoid predators and in order to keep from stressing the animals, the aquariums will set up a dark viewing area and dim light in the tank so that you can see what's in there. If you keep firing your flash and then it bounces off the glass, you're going to really annoy the other guests. And the staff, who will probably have a few things to say to you. I know that I always cringe when I forget to change my settings after moving from a flash-allowed area into a no-flash area and the thing goes off.
So, basically, if it's not allowed, don't be dumb and do it anyway.
But when it is allowed - it's your fish tank, or it's an area where they aren't worried that the animals are going to be harassed all day, every day by flashes - you can get some good shots.
I was at this absolutely massive tropical fish store called The Living Seas Aquarium last weekend for a tour and they allowed me to take photographs, flash and all. Most people heading in there are there to actually buy fish and fish paraphinalia, not just stand around and stare the fish like they would be at, say the Shedd Aquarium, so they didn't mind a few flash shots.
So, what happens when you do shoot against glass and do it wrong?
First of all you can see the flash reflected in the glass. You can even tell that my on-camera flash is rectangular.
You can also see any fingerprints and smudges on the glass. If you're the one in control of the environment, a quick swipe with some Windex will solve that problem. But most of the time we're not in charge of the glass and we'd look a bit silly whipping out a spray bottle and paper towel at the local zoo. Though, they'd probably thank you for it. :)
If your subject is right in front of you when you fire directly at the glass you get the above two problems as well as obscuring your subject.
So what can you do?
First, shift to a 45 degree angle or less to the glass. Shooting at a 90 degree angle to the glass (straight at it), is what gives you the bounce-back. So try something like this:
I've found that this can create a few different problems, but it solves the biggest problem of flash-bounce. However, most aquariums are set up to be seen from right in front of it and if there are pumps or hoses or things that have to be visible they're often put on the sides or in the corners and many times these are now in your shot.
The other thing you can do is try to avoid using the flash. Try turning up your ISO or widening your iris and see if you can get away with out it. If you're shooting a crustacean like a lobster or shrimp or something else that sits still, pop your camera on a tripod (again, if it's allowed where you're shooting) and just go with a long exposure.
The one place I absolutely cannot shoot is the shark tank at the Shedd. It's dark in the tank and since they're open water animals there's not even coral or rocks to give contrast. And since they're sharks, they never. stop. moving. So it's impossible to shoot down there since flashes aren't allowed. So if you have a moving target, you may just be out of luck if they didn't give you enough light in the habitat to get good, quick shots.
If you've got good equipment, a flash diffuser would obviously help. I've made a poor-person's diffuser out folding up a piece of wax paper and holding it in front of my on-camera flash. It helps when shooting shiny things like some of my ceramic work, but it's not a huge help when trying to shoot into an aquarium full of water.
So, while not the most advisable thing ever, you can shoot through glass using your flash if you're careful with how you do it.