The golden triangle of photography consists of three major settings. This is probably the biggest thing that sets apart DSLRs from compacts and phones – the ability to change (at least two) of these.
Aperture or F stop
The aperture of something is the size of the hole. Imagine a cardboard box with various sized holes cut out. The larger the hole, the more you can see out of it because there’s more light coming through. The same policy applies to cameras. When you get a lens, it normally shows you the lowest aperture it can get to. For example, the Nikon 35mm I use can get down to 1.8 (the numbers are arbitrary for the most part, just remember – the smaller the better) whereas the 70-300mm only gets down to 4. The relationship between them isn’t linear – let’s get mathematical. It goes up in an odd sequence. 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22… start on 1 or 1.4 and multiply by two to which gives either the normal or bold, put these two sequences together and you get a common range of apertures. There are intermediates but this sequence explains that when you go from 2.8 to 1.4, you’re letting in 4 times the amount of light (jumping 4 gaps, each gap being a multiple of 2 brighter). So why? Well, the more light you let in, the faster you can take the picture. This is especially useful in low light conditions where you usually get blur because the camera tries to compensate by slowing down the shutter speed (discussed later). Also, when you’re on the lower end of the apertures, you get a shallower depth of field which gives that nice blurred background effect lots of people love, in addition to bokeh which are circles of out-of-focus light. This can be tricky when you’re at really low apertures as sometimes it’s so shallow you miss things you’d prefer to stay in focus.
This is another setting you can adjust on DSLRs. When taking a picture, the shutter has to open and close to let light hit the sensor at the back and make an image. To see how this works, close your eyes, open them really quickly and close them again (a bit like a reverse blink). You get a freeze frame for an instant of what you saw for the moment your eyes opened. This is how shutters work. On DSLRs, you can control what is essentially the ‘blinking’ speed. This can range from 1/4000th of a second (really fast) to 30 seconds (a really long time). Now try this with your eyes. I doubt you’d be able to blink for 1/4000th of a second but we can all open our eyes for 30 seconds without much difficulty. When the camera blinks for 1/4000th of a second, it lets in so much less light than at 30 seconds. This can be useful for different conditions. For example, when taking night time pictures of stars, 30 seconds is needed as there’s barely any light so the camera needs time to gather enough for stars to show up. When taking a picture of a tennis match in midday sun, you need it to be fast to capture the ultra speedy movement of the players. Here, light is less of an issue as the sun is blazing so you can let in light over a shorter period of time as there’s so much of it! As with everything, there is a compromise. When you’ve got your shutter open for longer times you risk blur. On a tripod with a prime lens (these have no zoom but big apertures) you’re fine, but with a zoom lens in your hand in a poorly lit room, you’ll struggle to get decent pictures unless you slow down the shutter to 1/30th, 1/20th. Here you’ll get blur as you’ll start to shake in that period of time.
Once you’re comfortable with shutter speed, you can get creative. ‘Light painting’ makes use of long exposure times and bright sources of light, for example, traffic. To do this, you’ll probably need a tripod to keep it still. Drop the aperture to around f22 and have the shutter open for a long period of time. As traffic streams past against a dark background, you’ll paint streams of light with their headlamps and tail lights which make for some cool pictures. Sports events and things such as snow need really fast shutter speeds to essentially ‘freeze’ them in the act. For this, you need a big aperture (low number, remember!) as you’re allowing less time for light to go in.
This setting is probably familiar as you can change it on most compacts, even phones. It’s your camera’s sensitivity to light. Jumping from an ISO of 100 to 200 means you’re essentially making the sensor twice as sensitive to incoming light. This seems too good to be true, why not have it super sensitive all the time? Well, there is a compromise to be made in the way of noise. This is little bits or flecks or grain that show up on pictures when you crank it up to 3200 or 6400. this isn’t necessarily a bad thing, in fact, I’d rather crank it up, get the picture and edit it out later, rather than soldier on with a low ISO, get a blurry picture and lose it altogether. However, it is something to take into consideration. The rule is to keep it as low as manageably possible. This is because at low ISOs you have a higher dynamic range. This means that the camera is better able to tell the difference between light bits and dark bits of the picture – useful when there’s strong light sources as they cast shadows which might just appear black or the sky can be totally washed out at higher values.
The golden triangle
These three comprise of said triangle because they’re all related. Put your camera in P and it estimates, according to the conditions, what you’ll need. Aperture and shutter speed are pretty much inversely related. IF you’re on A (aperture priority – you set the F stop) and you drop it down low, the shutter speed goes up. Put the camera in S (shutter priority – you set the speed) and set the shutter to 1/10th of a second, the camera will reduce the aperture to stop too much light going in (which results in a pure white picture) ISO can help either way, if you turn it up, shutter speed can go up or you can afford to reduce aperture and vice versa. Put the camera in M, however daunting that may be, and you’re in full control. This can be useful because sometimes you want the picture to look a particular way and the camera might not get that. It’ll constantly threaten you with “subject is too dark/bright” warnings but experiment. I can’t tell you what settings to use as it’s individual to everything and everyone but give it a go and you’ll soon find your feet.