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The buttons you press on a camera to produce the right exposure in low light are all the same as when you shoot in the middle of the day. The same rules of exposure apply, it’s just a little harder to get there.
When there’s less light in a scene, you have 2 choices: create more light yourself, or change the settings on your camera to react differently to the light available.
This tutorial will show you how to do that.
If you’ve not yet read the tutorials inside my Understanding Exposure blog post, I strongly suggest you go back and read them now – there’s a lot more to it then you may think.
Putting that aside, you basically have three ways of getting more light into your camera in a low light situation; aperture, shutter speed and ISO.
This is the hole the light passes through in your lens; the wider it is, the more light you let in. Rather confusingly, the wider the aperture, the lower the f-number – bear that in mind.
This step isn’t particularly useful if you’re still using your standard kit lens as you’ll find that your maximun aperture is somewhere around f/3.5. This won’t let in enough light for good results.
I suggest buying a cheap yet effective prime lens with a maximum aperture of about f/1.8 (Canon EF 50mm f/1.8 ii) – this is commonly referred to as a ‘fast’ lens as it allows you to take photos at faster shutter speeds.
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The photo below was shot on film but, if i remember rightly, it was f/1.7 for 1/30 of a second at ISO 200.
The point here is that, if you want to take a well exposed photo in low light, you need a lens with a wide enough aperture to let more light in. Setting your lens to stop at f/1.8 actually lets in 4 times more light than f/3.5, which is a huge difference for a small change in number.
A wide aperture will produce a shallow depth of field. There’s no way around this without making your aperture narrow again and increasing the ISO or slowing down your shutter speed.
If you’re taking photos of groups of people in, for example, the pub, be careful about how wide your aperture is as you’ll end up with half of the people out of focus. This is a good time to use the flash but take my advice: invest in a proper external flash unit, it’ll make a world of difference.
Shutter speed is the second step in creating an exposure and also affects how much light enters the camera – the faster the shutter speed, the less light will enter.
If you’re out and about in a low light situation, chances are you’re not going to have a tripod with you. Be careful not to select too slow a speed or you’ll end up with blurry photos.
As a rule of thumb, the average person can take a sharp, blur-free image by setting the speed to a fraction of the focal length. For example, to take a photo at 30mm, you would set the shutter speed to 1/30 of a second. Any slower and motion blur is likely to occur.
It’s worth noting however that this rule is only relevant to full frame cameras. For a crop sensor, due to its magnifying effect, you would be better off choosing a speed of 1/45 of a second and you’ll need to drastically increase your shutter speed if the subject is moving.
If you happen to have a tripod with you and you’re shooting a still object, you can increase the shutter speed to virtually as long as you want. I recommend shining a torch on your subject so that you can focus properly, then use an external shutter release trigger to minimise camera shake.
Another technique worth trying is to use a relatively long shutter speed in a crowd of people. Capture their motion blur while the objects around them remain still, as shown in the photo below.
This is slightly trickier to manage on most cameras as, the higher the ISO, the more digital noise there will be, which can be pretty ugly.
If you’re struggling to get the exposure you’re looking for just by changing the shutter speed and aperture, the best thing to do is to raise the ISO. Remember how stops work though: doubling the ISO number doubles the amount of light that your camera can see.
I find that high ISOs on my camera aren’t very good at determining colour. You might want to consider changing your photos to black and white. That gives the photos a warm, old feeling and the high ISO actually adds to this.
Typically, I don’t raise my ISO above about 1600 – if I need more light, I use a flash unless it’s for artistic effect, as in the photo below shot at f/2.8, for 1/8 of a second at ISO3200.
Low Light Photography with a Flash
When you’re shooting groups of people in low light, it’s best to use a flash. As I explained above, if you have your aperture too wide, you’ll end up with a shallow depth of field and not everyone in focus.
If you only have a pop-up flash on your camera, you’re limited in terms of its uses but some of these techniques will still apply.
Firstly, just because you’re using a flash, it doesn’t mean that you can set your ISO back down to 100; if you do, you’ll start to lose background detail in the dark.
I like to leave my ISO on about 400 as I feel it gives an acceptable amount of grain and detail – all cameras are different so play around with yours to see what works best.
If you’re using an external flash, it’s best to bounce the light off of a wall or ceiling or to use a diffuser to make the light appear less harsh.
A lot of the time when a flash is used properly, someone without much photography knowledge can’t even tell that a flash has been used: exactly the reaction you want. The image below was taken at f/5.6, 1/50 of a second at ISO 500 with the flash bouncing off the ceiling.
Playing with light trails can produce some really cool results. All you need to capture this is a flash pointed directly at your subject with the shutter speed long enough to capture the blur that comes afterwards.
Have a look at my example below taken at f/11, for 5 seconds, at ISO 100.
Here are some tips to bear in mind when you’re using your camera in low light conditions:
- If you’re in a dark room and you want your photo to accurately capture the environment you’re in, the photo should be a little underexposed.
- Getting the desired photo takes priority over worrying about ISO noise.
- Keeping your elbows together and not leaning forward will help you to hold the camera steady for longer, allowing you to lower your shutter speed.
- Turning up your camera’s exposure compensation will help your camera to overexpose and, in darkened conditions, produce more accurate results.
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