The Triangle by Thackman

[tweetmeme]Imagine you’ve just put a pie in the oven. Now, the back of the packet said it needed 20 minutes at 120 degrees, but you haven’t defrosted your pie yet and the guide on the pack is for a fully thawed out pie. How hot do you want it? How long should you leave it in for and at what temperature? Welcome everyone to the world of photography.

Confused? This is where The Exposure Triangle can help. Imagine that the time you leave your pie in the oven for is your cameras Shutter Speed, the temperature of the oven is the ISO, and the state of your pie (frozen or thawed) is your cameras aperture. These three aspects of photography help to make up what is called ‘The Exposure Triangle’. Each one is directly related to the other, and a change in one will require an adjustment in the other two to ensure a properly exposed photo.

This analogy may seem strange, but I find this is one of the clearest ways to understand the relationship between Shutter Speed, Aperture and ISO. In order to understand the relationship though, you first need to know what each one is, and how it affects your photo.

Shutter Speed: The Shutter Speed is a fairly simple concept. It basically defines how long the shutter is open for. A longer shutter speed, such as two seconds (2″), means that your camera’s sensor (the CCD) is exposed to the light for longer, and this subsequently results in a brighter photo. Likewise, if you use a shorter shutter speed, such as one two hundredth of a second (1/200), then the camera’s sensor is exposed to the light for less time resulting in a darker photo. In the pie analogy, the shutter speed relates to the time your pie is in the oven. If you leave it in the oven for 30 minutes, it will be much hotter compared to leaving it in the oven for 10 minutes.

If you want to leave it in the oven for at least 30 minutes however, but don’t wish for it to get burnt, then the easiest way to avoid this is to turn down the temperature of the oven…

ISO: The ISO is the temperature in our pie analogy. ISO refers to your camera’s sensitivity to light and usually ranges from ISO 80 to ISO 1600. When light passes through the lens it is detected by the camera’s CCD (the camera’s sensor). If you have a higher ISO, such as ISO 800, then your photo will appear very bright. If however you choose a lower sensitivity such as ISO 100, then the image will appear darker. In photography it is best to leave the ISO at a lower level, around the 200 mark. Higher ISO’s will result in a noisier image, a bit like how having an oven at 400 degrees will burn the edges of your pie, even if you leave it in the oven for a very short time.

So you’ve got a low ISO, and you’re compensating for this low sensitivity with a slightly longer shutter speed. The additional light let in by exposing the sensor for longer should help you to properly expose your photo. But what about the frozen pie? After all, if the pie is frozen then you might need to leave it in the oven for longer, or perhaps turn the temperature up…

Aperture: The aperture refers to the size of the opening within your lens. Aperture is measured in F-Stops, where a smaller F stop such as F3.2 means a large opening, and a larger F-Stop such as F22 means a much smaller opening. If you increase the size of your aperture to around F3.2 then there is more space for light to enter, which subsequently causes your photo to be brighter. If however you choose a smaller aperture of F22, then there is very little room for light to enter, and less light enters resulting in a darker photo. In the pie analogy, a smaller aperture means a frozen pie, whereas a larger aperture means a well thawed pie. If your pie is frozen, you will need to leave it in the oven for longer or turn the temperature up. Thaw it out however, and it will be ready much faster.

A well exposed photo is a result of the correct shutter speed, the correct ISO and the correct Aperture. A nice warm pie is similarly the result of the correct time, the correct temperature, and a pie in the correct state.

The Exposure Triangle defines the relationship between all three of these photographic aspects. Hopefully this pie analogy will help to explain just how they all affect each other. There is no right or wrong setting for taking a photo. Sometimes you may want a longer shutter speed to capture the flow of a waterfall, in which case you will need a smaller aperture and a less sensitive ISO to compensate for this extra light. Sometimes you may be photographing at night in which case you’ll want to increase the sensitivity, increase the shutter speed and use a wide aperture to capture all the light you need.

The best way to fully understand The Exposure Triangle though is to get out there and take photos. Move the dial to M and shoot on full manual, and proceed to adjust each setting to see how they change your photo. Even the pro’s get it wrong the first time, but having the understanding of how they work together will allow you to end up with a nice tasty photo.

Nelson Falls of Tasmania

It’s often said that great photography captures, not only a scene, but its unique feeling and essence. Expressing these properties helps to bring your photo to life. When photographing waterfalls, the intricate and consistent flow of water is the trait that makes them such a beautiful scene, and because of this it’s important to try and capture the flow, motion and the colours of the water in your photo.
In this guide we’re going to learn how to capture a waterfall so that when you look at the photo, you feel like you’re right there.

Use a long shutter speed.

By using a long shutter speed you can capture the motion and flow of the water. In order to do this, it helps to have a basic understanding of your cameras exposure. You’re going to need to increase your aperture (higher F-stop) to minimise the amount of light entering the lens, as well as lower your ISO to reduce your cameras sensitivity to light. This will simulate darker conditions and allow you to use a long shutter speed without over-exposing your photograph. Aim for a shutter speed that’s between 1 and 2 seconds. This range will give you a silky flow of water and will still hold some of the waters texture. Longer shutter speeds will capture a smoother flow, but they can also become too surreal.
The two images below show the differences between a normal photo and one with a slow shutter speed.

Normal 1/15 second shutter speed

Slow 2 second shutter speed

Use a Tripod.

This is a fairly obvious step. If you’re using a long shutter speed then any jolt or movement of the camera will result in a blurred photo, so it’s essential that you have something to keep it still.

Do the complete opposite to what I’ve just said.

Sometimes a photograph of gentle silky water doesn’t depict the real mood of the waterfall. Sometimes a waterfall is raging and powerful. If this is the case, experiment with fast shutter speeds to catch the wild rush of water right in its tracks.

Use a Circular Polarised Filter.

If you’re photographing a waterfall in sunlight, your camera becomes susceptible to lens flare or glare from the water. Even in cloudy conditions, the angles of the rocks can reflect light into your lens. A circular polarised filter will help you to remove this glare.
It will also help you to blur the flow of the water. Think of the filter like a light pair of polarised sunglasses. It will eliminate the glare as well as darken the light entering the filter, which will allow you to use a longer shutter speed more effectively.
They can be fairly costly, but if you do any photography outdoors a polarised filter is an essential tool that will greatly improve the colours of your photos. It’s well worth the investment.

Bracket your photos.

Bracketing basically refers to taking multiple photos of the same scene at different exposures and apertures. As a result, you’ll receive a range of photos of a single scene with gradually changing settings. When photographing waterfalls, bracketing is certainly something you should try so that, when you’ve uploaded your photos onto the computer, you can pick the photo with the perfect level of blur in the water.
Remember to take a control shot first on auto mode, and then switch to shutter priority or manual mode in particular and take a range of photos with different settings.
Bracket your exposure using a fairly wide range. Try from 1/10th of a second to 8 seconds. This should give you a variety of photos, each with a different level of blur in the water.
Also experiment with different depths of field by bracketing your aperture.

Photograph at night time.

At night time, the darker lighting will be far more natural than anything you can simulate with your exposure. Even if you switch your camera to auto mode the settings should automatically allow for the smooth silky flow of water. The night scene far better suits a gentler, more docile flow of water, so if your waterfall is raging and strong, it’s probably best to photograph it in daylight.

That’s pretty much it. All you really need to do is find the characteristics of your waterfall, and then capture them in your photo. Hopefully this guide will help you do that.