In this article we’ll explore a bit why and how you can shoot great pictures using long exposures. Night shots with light trails or smoothed water are impressive, while very easy to obtain if you know how !
Let’s get started 😉
Why use slow shutter speeds ?
This is a legitimate question. Why would you deliberately use a slow shutter speed when your camera allows you to take good enough pictures at night, thanks to high sensitivity, or a flash for instance ?
Well, for some photographers it’s all about having a low ISO and getting the cleanest image possible. But there’s another important factor : what the sensor sees is different from what you eye sees. Long shutter speeds allow you to get creative.
For example with a 1/100 exposure -which is neither too slow or too fast-, the sensor will gather all the light during a hundredth of a second. This means, except if your subject is moving fast, it won’t be blurred. With a 1 second exposure, everything happening during this second will be captured, so it’s not really a good speed to shoot portrait or street, except if you’re looking for a lot of motion blur.
If you want to shoot long exposures, you have to be aware of 3 key things : the steadiness of your camera, the amount of available light, and your subject’s speed. You can work your way around with those three simple things.
Because most of the time you’ll want to have a sharp image, you need to keep your camera abolutely steady. This means you have to use a tripod, or any reliable surface on which you can put your camera. Now, you have to release the shutter without touching the camera, because even this motion would cause blur. There are two ways of achieving this : either you have a cable (or a wireless) remote, or you can simply use a 2s or a 10s self timer for example (you simply have to press the shutter, get your hands off the camera and let it take the picture).
However in some cases you can voluntarily play with long exposures and a handheld camera. It can work for fireworks, for example. The light trails here aren’t all smooth here because I didn’t use a tripod, but I’m fine with the result.
Long exposure means more light, and sometimes even too much. Available light determines what range of speeds you’ll be able to use. Fortunately a few settings and tools can help you get the correct speed.
Shooting with slow shutter speeds, my ISO is almost always at the minimum (100 on my cameras), so there is as less noise as possible. As for the aperture, it really depends on what effect I want to achieve. Most of my slow shutter shots are taken in speed priority mode, we’ll talk about that a bit further.
Here for instance I didn’t want the scene to be too bright, and I used a very small aperture (causing the “starburst effect” on the street lights in the background) to match the speed I wanted.
“Well, this works great by night, but what happens in the daytime?” you could ask me. Indeed by day, it’s often too bright to get a slow enough shutter speed while using only your camera settings. You have to rely on some exterior help. That’s where neutral density filters (aka ND filters) come into play. When you mount them in front of your lens, they simply allow you to get less light coming in, while keeping accurate colors and contrasts.
This is the part where you get creative. The speed of your subject and the effect you want to achieve will determine which shutter speed you want to use. By the way, if your camera has a shutter priority mode (referred to as “S” or “Tv”), it’s now time to use it ! This way you get to choose the speed, and the camera automatically sets the ISO and aperture.
It is fairly easy to make people disappear from a frame using long exposures. For instance here, in front of Angkor Wat at sunrise, the place was crowded, but a 13s exposure was enough to remove everyone from the shot. You can still see the ghostly trace of someone passing by, above the right puddles in the sky.
Here is the opposite case. I wanted to take a self portrait, but there wasn’t enough light to use a fast shutter speed and freeze the action. So I chose an intermediate speed of 2,5s and a self timer, walked into the frame and kept steady.
I’m a bit blurry but still recognizable.
You can also freeze people using long exposure and a flash, but this will be covered in an upcoming article.
Another effect you can obtain with long exposure is softening and smoothing water. This way you can make it contrast with all the static elements of your picture. This first picture was taken with a 1/400s exposure, far from enough to give a silky look to the river…
… but compare it to this picture of Notre Dame with a 6-8s exposure, and it feels completely different !
In general you need a few seconds exposure to smooth a river, but for a waterfall -where water obviously moves faster-, you can even use shutter speeds around 1/40 or 1/30 to achieve the same effect.
Light trails are probably the most recognizable trademark of this technique. You can use any moving source of light, from car headlights, to stars, and even fire jugglers, like here on Notre Dame’s forecourt.
The key is anticipation, you have to plan where the source(s) of light is going to move. For instance with cars I often use a speed around 8s so that the headlights are long, and not trimmed in the middle of the image. For this image I also had to struggle with the bridge’s movement, which was inducing motion blur, I had to try for 20 minutes until I could get the shot.
Finally, you don’t even have to rely on exterior sources of light, you can go play with your phone’s torch within your frame, and do bit of light-painting. The possibilities are infinite. This last picture showcases light-painting as well as blurred out bystanders.
What you have to remind here is, there are no rules in photography. Whatever works for you will always make your best pictures. You have to experiment, get used to the shutter speed mode and to different subjects. Eventually it will become like a second nature and you’ll be able to visualize your shots even before the shutter has been released.