An Introduction To Long Exposure Photography

An Introduction To Long Exposure Photography

‘Long exposure photography’, as the name suggests, is a technique in which a relatively long shutter speed is used to introduce an artistic and surreal feel in the image.

This requires some explanation. Let me explain the ‘longer than usual’ part a bit.

Consider a normal photograph, say an image of your daughter, sitting on a pretty chair. When you take such an image, it is generally advised that you use a shutter speed of about 1/150th of a second or faster. Since the subject of the image is a child who is just sitting still, there isn’t much motion in the image. In other words, elements in the image are not moving much and hence a shutter speed of about 1/150th of a second should suffice.

On the other hand, if your daughter were moving around or running or playing football, you would require a lot faster shutter speed (say 1/500th or 1/1000 of a second) to counteract the motion of the subject and get a clear and sharp picture.

What I am trying to get at is this. The shutter speed of a camera is always dependent on the amount of motion present in the frame and on the level of desired sharpness. So, if you want to take an image of a race car zipping past you at breakneck speed, you would require a shutter speed much faster than if you want to take a group photograph at a wedding.

I left out a small part there. I did say “desired sharpness”. Of course, you always want the sharpest possible image, ALL the time!…. Right?……Well, not really. Sometimes photographers do not want to freeze all the motion and make the image look like a static frame. Often they want to preserve some artistic motion blur in the image and use it to show movement. Panning is a very popular technique that is used by many photographers to depict motion and use it to add more to the image. Here is all you need to know about panning: The Art Of Camera Panning | How To Introduce Motion In The Frame.

Theory Of Relativity

No, no this isn’t a Physics lesson; this still is within the bounds of photography. I promise, just keep reading.

It is a common misconception that an image when taken using a shutter speed exceeding a certain time period is called a long exposure photograph. Where people are generally wrong is, they think of only one such time period. That is however NOT the case. Long exposure photography refers to any such technique for taking an image where the shutter speed employed was longer than what was necessary for a steady sharp shot.

So if you require a shutter speed of say 1/100th of a second to get a nice, clean steady image of a landscape. Then any shutter speed longer than 1/100th of second is technically a long exposure. But it’s this longer than what is necessary shutter speed that creates the magic and transforms the movements of the frame into beautiful things.

Here is how that happens…

 The Objective

The fundamental objective of any photographer using the long exposure technique is to craft motion into something aesthetically beautiful. Now, this can happen in a lot of different ways and is only constrained by one’s imagination. Let’s take an easy example that you have probably seen many times.

long exposure image of a rock face with the sea below at sunset

Looks familiar?

But then there is something that doesn’t really look ‘real’, isn’t it? Yes, the calmness of the water. The water in the image looks so damn smooth and silky that it seems that there was absolutely no wind blowing that day. It might have just well be taken on the windless Moon. But we all know that is not the case. The secret here is a long shutter speed.

But how does a long shutter speed get the water silky?

The longer than usual shutter speed has nothing to do with the water per se but has everything to do with motion. Let’s compare this image to a normal everyday image so you would understand better, alright? You see, whenever you select a particular shutter speed to take an image, what you are actually defining is a time period during which the motions in the frame are so minuscule and insignificant that they are practically nonexistent in the final photograph.

portrait of a woman who has very colorful and shiny hair

So if you use a 1/150th of a second shutter speed to record a portrait of a woman, what you are actually doing is deliberately selecting a time frame which is sure to not be enough to register any movement in the frame. Any minor hand or head movement that the model may still have would simply not be recorded. The resulting image would be sharp (considering that it was well focused).

Now if you think a little hard, isn’t this all you have been doing when deciding on the shutter speed? Deciding the precise amount of time that would be enough to record the subject but not cause any blur?

What Then Causes Blur?

Blur is actually a result of an extended period of image recording. What happens is pretty simple. Say a photograph with a human subject requires a minimum of 1/100th of a second shutter speed to freeze the motion. If you select a shutter speed longer than 1/100th of a second, what happens is the image sensor of the camera is exposed to the light long enough that it also registers the movement of the subject, thereby causing the blur.

The blur is nothing but the movement of the elements recorded in an image.

You may have experienced it yourself if you have ever shot some low light or night time photography. When the amount of ambient light is low, to ensure enough amount of light to expose an image properly, generally all cameras extend their shutter speeds. Lower the amount of available light, longer are the shutter speeds. This longer duration may sometimes introduce some amount of blur in your images. Especially in the parts which have any movement in them. Dimly lit restaurants, concerts, nightclubs, etc are prime candidates for this category.

Circling Back

Our little detour aside. Now that we have a pretty good idea about how the image turns out blurry and how to stop it, let’s get back to the original topic, long exposure photography.

So what are we trying to do using a longer time duration?

In a sentence, what we try to do in a long exposure is to use the blur artistically and to encapsulate a longer period of time into one image. Let’s take an example to explain this better.

Top angle shot of a city at night with streaks of light caused by car tail and headlights
Photo Credits: Dylan Chung

In the image above, the photographer has used the streaks of light caused by the head and tail-lights of many cars. Since the shutter speed was so slow (in minutes probably) and the cars so fast, there was bound to be some blur. The photographer intentionally made the decision to register just the brighter lights of the cars and erase the actual cars completely. This is an image which is sincerely something you cannot see with your naked eyes.

The image we started the discussion with, also used this exact phenomenon in a little different way to smoothen out the water. When the shutter speed selected was long enough, the tiny, repeated waves on the water’s surface would all turn out to be just translucent blur. Making the water looks much calmer and smoother.

long exposure image of a rock face with the sea below at sunset

You can turn up the heat yourself and use this knowledge to create all kinds of images. There are no bounds at all.

The Process

Well acquainted with the theory now, we are ready to jump into practicals. As obvious as it is, the most important thing that you need to make a long exposure image is the ability to drop the shutter speed. Now, this is already done for you when the amount of available light is naturally low. Lower the amount of ambient light, longer the shutter speed required, remember?

Bright lights are the one which is registered first when using a long shutter speed. A very easy example is Fireworks Photography, which is done exactly this way. Read How To Photograph Fireworks The Easy Way | A Step By Step Guide where I dive into it deeper.

Low Light/Night Time Photography

Owing to the already favorable low ambient light, it is extremely easy to just drop the shutter speed. This is the very reason why most of the long exposure images you see online are shot at night. The list of gear that you need to use this technique is as easy as it gets. All you need are these:

  • A camera with adjustable shutter speed
  • A lens (whatever suits the image)
  • Tripod
  • Remote shutter release

Since the main thing that you want to capture through your long exposure image is motion, you need to be extra vigilant about the degree of motion the elements of the scene are going to produce and how that would work in conjunction with the rest of the image. Like any other image always carefully choose a good clean background, find a good perspective and create an amazing composition. The creative blur is supposed to just add a little extra zing to the image. It simply cannot make a bad image look good. Keep it straight and follow the basics first.

Once you are happy with the composition, set up the tripod and mount your camera on it. Focus on your subject using either the viewfinder or the LCD (whatever suits you). Do remember to lock focus once you are satisfied. Do NOT leave your camera on AutoFocus when you actually expose for the image. If you use Back Button Focusing all you have to do is let go of the AutoFocus button and it would lock automatically.

For camera settings, always use the lowest possible ISO. The aperture and shutter speed would vary depending on the amount of available light, elements in the scene and the type of image you want to create. There is no way to predefine this. You have to take some trial shots, see what works and make adjustments accordingly.

If you have a remote shutter release, always use it to initiate the shutter. Long exposure images are notoriously prone to even the slightest of camera movements. You want to eliminate as much of it as possible. Keeping pressed the shutter button for an extended period of time is sure to welcome some amount of camera shake. Avoid it at all costs. If you have a DSLR you can even use the Mirror Lock Up function to be just that extra bit careful.

Shoot away now!

Daytime Long Exposure

This is a bit tricky. On a normal sunlit day, the average shutter speed you require to expose an image properly would be around 1/2000th of a second. It cannot go any slower than that, because the amount of light is way too much. But we also need the shutter speed to be at least a few seconds to garner any form of a blur.

So we do what is required, reduce the amount of light that enters the camera. How? Using a sunglass for your camera, also known as a Neutral Density filter (ND). An ND filter is nothing but just a dark piece of glass that is designed to reduce the amount of light that passes through it. Exactly the same as your sunglasses.

ND filters come in various sizes, shapes, and strengths. Each filter is graded according to the amount of light they are able to limit. For example, a one-stop filter is capable of reducing the amount of light entering your camera by half. It also means that you can attach such a filter onto your camera and then with all the other settings the same, reduce the shutter speed by a stop. Isn’t that wonderful?

daytime long shutter speed image of an urban landscape

So, problem solved!

All you have to do now is estimate the shutter speed that would allow you to make the image you want to. Calculate the amount of light you need to block to use that shutter speed and just attach an ND filter that matches the strength. All the other processes remain exactly the same as Night Time Long Exposure. We just had to travel this extra mile to adjust for the amount of excess light.

Okay, okay that flew over your head. Here is an example which should be right up your alley.

Let’s suppose the actual settings you required to take the image WITHOUT the ND filter were as follows:

  • Aperture: f/5.6
  • ISO: 100
  • Shutter Speed: 1/2000th of a second.

But you need to bring down the shutter speed to at least 4 seconds to blur out certain parts of the image. So keeping the aperture and the ISO constant, to get to the shutter speed of 4 seconds from 1/2000th of a second you require a 13 stop ND filter. If you are good with calculations you can just as easily calculate it on your own. If not, you can just download an app which would do it for you. It’s not as hard as it looks, trust me.

Final Tips

All done and dusted; here are some tips which should help you skip the most frequently committed mistakes and save you a lot of time and frustration:

  • The scene you want to shoot SHOULD have some degree of movement in it. Static objects do not lend themselves well to long exposure photography.
  • Faster the element in your scene, greater the amount of blur it creates. Slower the elements, sharper they appear
  • The images which show the passage of time generally look the best.
  • For composition, try and create one where static and moving objects coalesce into one and complement each other.
  • Never forget to lock focus before you start to shoot
  • Substituting a tripod or a remote shutter release is not a good idea. Just get one, you don’t have to break the bank for it.
  • Religiously check your histogram after each of your shots come out. On the LCD, they may look a lot different than the real image. Just be sure.
  • Prevent light leakage through the viewfinder. When shooting, be sure to cover it up with something.
  • Explore all your creativity. Longs exposure are used for many purposes. Make water look silky, the clouds streaky, steel wool images, light paintings, star trails, sunsets, sunrise, make people disappear from shots and many more. Always be on the lookout for the next great opportunity to use this technique.

That is all folks.

I hope you will find sandwiching time and capturing motion creatively into an image as enjoyable as I do. We, as photographers, always want to avoid blur at all cost. This is one of the rarest instances when we not only welcome it with both hands but also use it to further our image.

Let me know in the comments bar below if you have any questions. I would be more than happy to help you out.

Keep shooting amazing.

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