How To Create Smooth Long Exposure Photography

If you haven’t already read my journal entry entitled “Balancing the Three Parameters of Your Camera - Aperture, Shutter Speed, and Focal Length” go ahead and do that first. I’ll wait.

I promise. This entry will make so much more sense if you take some time and read that one first.

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… are you finished?

good.

What is Long-Exposure Photography?

Long-exposure photography (as a subgenre of the larger genre of art photography) follows the same basic principles as non-long exposure-photography. In fact it has almost everything in common with it. The main (if not only) difference is that the shutter speed is lengthened past “proper” exposure to purposely create motion blur.

This "intentional” motion blur is very different from an accidental one.

a long exposure of snow falling showing the motion and direction

I like to think of long-exposure photography as an art form that expresses the movement of life but in a still frame. Easily the most used subject of long-exposure shots is water (rain, waterfalls, ocean waves - you get the idea). But you will also see a lot of vehicles, people, animals, etc. expressed in a long-exposure photograph. It’s the easiest way to show a subject has motion or action.

Because long-exposure photos only have to be longer than what would be required to freeze the in-frame movement, even a slightly longer shutter speed that has some motion blur to it can be considered a long-exposure image. And you can achieve this by affixing your camera to a tripod and photographing a moving subject or purposely moving your camera while exposing an image

a long exposure of a lake that turns the rippling water into a glassy smooth surface

What is “proper” exposure

Short answer? There’s no such thing. Proper exposure is in the eyes of the artist (or the commissioner) of the artwork. My idea of how a scene should be exposed might be slightly different than how you want a scene to be exposed. Which one of us is right? The one holding the camera (or the one paying the photographer.)

As discussed in the entry “Balancing the Three Parameters of Your Camera - Aperture, Shutter Speed, and Focal Length” (go check it out if you ignored my earlier suggestion), your first requirement is to determine how you are pre-visualizing the composition. From there, set your focal length for your composition, set your aperture, and then the shutter speed.

Shift your Stops

One aspect of film photography that I am growing more comfortable with is the practice of shifting stops around to keep the same exposure settings to achieve a different “look.”

Illustration Time:

Shutter speed, aperture, and ISO (being the primary aspects of photography that affect an image’s exposure) are all set to get the scene at the exposure I’ve pre-visualized. My subject is a single plant growing between cracks in a stone staircase. Being a windy day, I know that the branches and leaves will have a motion blur if my shutter speed is too slow. I set my camera to shutter speed first since I want to freeze motion - that’s what I am most concerned with. 1/80 is fast enough, which means I have to open my aperture to f/5.0. ISO is 160 (base ISO). My wide aperture and long focal length create a pleasing shallow depth of field.

See image below:

I take my exposure, and it’s a basic photo of a little plant growing out of stones. Now I want to experiment (YOLO, amiright?). Slowing the shutter to 1/13 forces me to close the aperture down to f/13. I achieve the same exposure, but the plant’s top leaves are now ghosting in frame creating an artistic and visual expression of the wind. However, due to the narrower aperture and wider depth of field, the stone wall is now fully in focus.

See image below:

In the illustration, I was forced to shift stops from one aspect of the camera to another in order to achieve the same exposure setting. But what if I wanted to get the same shallow depth of field that f/2.8 offers while using 1/30 as my shutter speed? That is where a Neutral Density filter comes into play.

Neutral density filter

At a certain point in your photography research, you’ve probably heard someone talk about using a filter for their lens. There are a literal ton of different types of filters for all different purposes and all different sized lenses. One of these styles of filter is the Neutral Density filter (ND filter for short). The primary purpose of the ND is to darken the scene by specific “stop” values. In other words, you can buy an ND filter that has 4 stops of light reduction to darken the scene from our earlier illustration so that you can slow down the shutter by 4 stops without having to close the aperture by 4 stops. Pretty nifty, right?

Variable ND filters (a little more expensive than single stop NDs) can stop down in gradual stages - hence the name. I have two sets variable NDs that I use when I film that allow me to be ultra precise in my exposure settings. They darken the scene from 1 all the way to 9 stops of light reduction. And they can technically be stacked on top of one another, so I guess in reality, I could actually go down 14 stops. Totally unnecessary unless I’m photographing 10 minute long exposures.

My other collection of ND Filters are square and rectangular made by Polar Pro (I am not affiliated or sponsored, but go ahead and check them out if you’d like.) And I use them exclusively for my photography. Just like my variable filters, I can stop down specific numbers, but unlike my graduated NDs, they are only in specific stop increments.

Purchase suggestion

Ok, so what do you buy? I mean, let’s be honest; that’s probably what we’re all most curious about. You’ve been scouring the internet for info on long exposure photography and what kind of gear you need for it. So cut to the chase, right?

My suggestion is to start with a stop-down method of darkening your scene. Set your camera to “proper” exposure and then stop down the aperture so you can slow down the shutter speed. See what 3 stops of light reduction looks like. See how going down another 3 stops looks. Most lenses are easily capable of stopping down the aperture by at least 6 stops. If that’s not a long enough exposure, then you know you’re going to need to get a Neutral Density filter capable of at least 6 stops of light reduction.

From there, decide if you want to go the square filter route or the round variable filter route. The primary benefit of the square ones is you can get something called a graduated ND filter. It is darker on one end of the rectangle than on the other end so you can darken the sky more than the ground. These are mostly used when photographing sunsets and sunrises. Variable ND filters give you a lot of control in light reduction, and they’re a lot lighter and easier to set up.

You can get a nice variable ND for a couple hundred dollars. To get into a good square and rectangular filter systems is easily $600. And usually you’re going to have to buy many extra filters because they never have all the ones you need in their starter kits.

Experiment with what you have. Use cheaper alternatives until you know what you need. Then invest in the right system.

Implementing the ND Filter

Equipped with your ND filter of choice, you’re now ready to take long exposure photography to the next level. Using a filter, you’ll now be able to keep your shallow depth of field and extend your shutter speed without over exposing your photo.

Conclusion

It’s always fun to experiment and test your creativity. Long exposure photography is a great entry into different artistic photography styles. Give it a shot and see how a camera renders a scene differently in long exposure. Then try freezing the action and compare the two. We learn by asking questions, investigating, experimenting, and “failing.” So don’t be afraid to do any of those things.

-Jude