Ever since moving to the Pacific Northwest, I definitely have had my fair share of photographing waterfalls. In fact, I became infatuated with landscape photography after realizing that I could, in fact, photograph a “moving” landscape and make it amazingly beautiful! The main thing that pulled me in was blurring water; I was able to transform splashing, fast-moving water into a cotton-candy wonderland.
Creating photographs like these is relatively simple, you just need a few pieces of basic equipment to make it happen. Basically, to create the misty, cotton-candy water effect, you need a very long exposure. Sometimes the light is too bright for the camera to leave the shutter open long enough, so you need to block the light that is coming through the lens so that you can prolong the exposure time and use a slower shutter speed. The best way to do this is with a Neutral Density (ND) filter.
What is a Neutral Density Filter?
An ND filter is a dark piece of glass in a neutral color that blocks the light coming into your lens. They come in various “stops”, and block light according to the intensity of the filter. Sometimes you can create long-exposures of water without them, but the scene would require a dark, overcast day with very little (to no) sunshine. And on the days when it is bright, ND filters are the key to long exposures.
What scenes work best with long-exposures?
The most important thing you will need to get a good long-exposure is something that is moving. Oftentimes this will be water, or even clouds. But you can experiment with the filters and photograph moving people, or cars during the day, and more.What gear do I need for long-exposures?
Regardless of the type of long-exposure photography you are wanting to create, there is some essential gear to ensure success with your photographs:
- Sturdy tripod
- Camera you can set to BULB
- Neutral Density filters (for blurring water, clouds, etc.)
- A timer or long-exposure app
Which ND Filter setup should I buy?
There are two main types of ND filters: Circular and Square/Rectangle (100mm). Each of them has pros and cons, and so I have listed a little bit about them, along with some things to consider when deciding which one you should use with your photography.
The first type is the CIRCULAR filter. These screw on to the front of your lens, just like any other filter. They come in different size filter rings to fit individual lenses, and come in various ranges of stops. If you are just starting out with long-exposure photography, you’ll probably want to start with one of these and see how you like it before investing in a full 100mm square/rectangle filter system.
- Easier to use and carry (less setup required)
- Less potential for light leak (the filter is “sealed” against the lens)
- Only good for one type of lens size (you would need to purchase more than one of the same filter if you have different sized filter rings on your lenses)
- Stacking filters can result in lens vignetting (darkening around the edges of your image)
SQUARE or RECTANGLE FILTERS (100mm):
Square and rectangular filters are good for photographers who create long-exposures regularly and want to have one filter for all lens sizes. These filters require a filter holder and adapter rings to allow placement on any size lens. This is the type of ND filter setup I use and would recommend to anyone who is serious about long-exposure photography.
What you will need for this setup:
- Filter holder (Formatt Hitech and Lee are two good brands to look into)
- Adapter/step-up/step-down rings (these allow you to connect the filter holder to the lens, and come in different sizes)
- 100mm Filters
- One filter fits all lenses (requires a universal filter holder)
- Easier to stack filters with less chance of vignetting
- You can add a circular polarizer on the front with a special attachment ring
- More options for filter types, including graduated ND filters (clear on top, ND on the bottom), and many more
- Needs additional equipment (Filter holder/kit)
- Larger, so they take up more space in your bag
How to manually calculate a long exposure
When I use ND filters, sometimes the exposure time exceeds 30 seconds. Because most cameras cannot calculate an exposure time beyond 30 seconds, then you will need a way to do the math and determine your long exposure time. You can do it manually if you like; it’s really not too complicated. Here’s how:
- First, get a base exposure of your image without the filter. Set your camera to the aperture you want, and then use Aperture Priority or Manual Mode and take a photo. Let’s say, for demonstration purposes, your exposure is 1 second.
- Next, put your filter in the front of your lens. (For this example, we will be using a 6-stop ND filter.) Keep your aperture the same, and meter ONLY for the shutter speed.
- At this point, your camera will probably be flashing the 30-seconds in the display. That is telling you that the exposure will be underexposed at that setting and needs a longer exposure time. So, switch your camera to BULB (you’ll also need a cable release) and calculate the exposure.
- Here’s how you do the math. You take the original exposure time (1 second), and double it SIX TIMES, as you are using a 6-stop filter. It will look like this:
Start at 1 sec –> 2 sec –> 4 sec –> 8 sec –> 16 sec –> 32 sec –> 1 min 4 seconds
- Then, press the shutter button (using the cable release), and hold the shutter open for 1 minute 4 seconds. You should have a nice, blurry-water effect in your photo!
Using Smartphone Apps to calculate long-exposures
If you don’t want to do math every-time you create a long-exposure, try using my preferred method of a smart-phone app. There are some pretty good apps on the market that make it really easy to calculate exposures, and I use them almost every-time I photograph running water.
Here are some of long-exposure apps you can check out:
Slower Shutter (iOS, $0.99)
ND Timer (iOS, $0.99)
ND Filter Calculator (Android, Free )
My Method for Photographing Long-Exposures
Here is a typical photographic workflow that I use while out photographing long-exposure landscape photographs:
- I start by setting up the basics with my camera (on a tripod, btw) and other settings: lens choice, composure, focus, and aperture.
- Next, I set my camera to Aperture priority and create a base exposure and make sure that my ISO is set to ISO 100 (the lowest setting).
- Then, I place my ND filter in front of my lens and make sure that my cable release is attached to my camera.
- Now it’s time to see what my exposure will be with the ND filter attached:
While still in Aperture priority, I check the settings on my camera. Sometimes there is enough light coming through the lens to keep the exposure at 30-seconds or less. If this is the case, I press the shutter to expose the photo, and then preview it on the back of my camera.
However, if the 30-seconds number is flashing on my camera, that means that the exposure time will be greater than 30-seconds and I will need to use a separate timer. (Keep on reading … –>)
- Now, I set my camera to Bulb mode.
- Using my iPhone long-exposure app, I enter the base-exposure shutter speed and ND filter type (for me, this is either going to be 3-stop, 6-stop, or 10-stop filter, as those are the ND filters I currently own).
- The app will tell me how long I need to leave my shutter open. So I start the long-exposure timer app on my iPhone, and then I press the button on my cable release and keep it pressed until the timer goes off. (BTW, most cable-releases have a “locking” feature where you can lock the shutter down so you don’t have to press it with your finger the whole time.)
- At the end of the exposure, I preview the image on the back of my camera and make changes as necessary.
Here is a gallery of some before-and-after long-exposure images to show what types of effects you can get with ND filters. The image on the LEFT (“before” photos) were photographed WITHOUT a filter, and the photos on the RIGHT were photographed WITH an ND Filter (3-stop, 6-stop, or 10-stop). Note that the “before” images are unprocessed and straight out of camera, while most of the long-exposure photos have additional post-processing applied to them.
Click on the first photo and scroll through to see them larger. Shutter-speed is also listed in the captions so you can see the difference between the base-exposure and the long-exposure.