If you've never used a neutral density filter before, you're missing out on a great opportunity.
That's because neutral density filters help you slow time down, creating gorgeously dreamy photos like the one shown above.
I think for some people, the barrier to getting into long exposure photography is simply not understanding the tools needed to create awesome long exposure photos.
In this guideline, I offer a solid workflow for maximizing the quality of your photos by learning how to use ND filters.
Neutral Density Filters in a Nutshell
The primary reason for using neutral density filters is to cut down on how much light is allowed to pass through your camera lens to the camera sensor.
These filters are usually made of glass (though cheaper ND filters are sometimes made of resin), and attach to your lens with a filter holder, as seen above.
Neutral density filters come in all manner and sort of strengths, with the most popular versions being 3-stop, 6-stop, and 10-stop filters. As you can see in the comparison above, the higher the stops, the more light-blocking power the filter has.
When you use a neutral density filter, it enables you to extend your shutter speed to blur the effects of movement, as seen above.
This is advantageous in situations in which you're photographing waterfalls, rivers, the ocean, moving clouds, and so forth, during the day, and want to have the dreamy effects of perfectly smooth water.
Without an ND filter in place, you can't slow down the shutter enough to get the blurry movement you want without the photo being incredibly overexposed. Thus, the need for an ND filter.
Editor's Tip: The quality of the filters you use will impact the quality of your images. See what top-quality ND filters look like.
Neutral Density Filter Guide
Step 1: Compose the Shot
Before you attach your neutral density filter to your lens, it's important to compose the shot first.
That's because once the ND filter is on your lens, each photo you take will take 30 seconds, 1 minute, 3 minutes, and perhaps much, much longer.
You don't want to wait around that long to check your composition, so this way will save you a lot of time.
Naturally, since you'll be dealing with long exposure times, having your camera on a stable tripod is an absolute must. I'd also add that using a camera remote, or at the very least the camera's self-timer, is a must as well, just to be sure you have the best chance at getting a sharp photo.
Step 2: Take a Baseline Photo
Composing the shot isn't the only thing you need to check before putting your neutral density filter in place.
You need to take a test shot (or two...) to check the sharpness of the image.
Once the filter is in place, your camera's autofocus system will struggle to find its focus point because it relies on detecting contrast, which depends on light.
Since these filters block out light, it makes it difficult if not impossible for autofocus to work.
So, compose the shot, take a baseline image, and use the camera's LCD to zoom in on the subject to ensure it's tack-sharp.
You also need to dial in the correct exposure settings at this point.
In many cases, doing this in manual mode so you can fully control aperture, shutter speed, and ISO is the best way to go.
However, if you're not quite comfortable shooting in manual mode, give aperture priority mode a try.
This mode gives you control over the aperture and ISO while the camera controls the shutter speed to get a well-exposed image.
To get the baseline image, aperture priority will work just fine.
Learn More:
- Simple Tricks to Getting Sharp Images With Your Camera
- Landscape Photography Primer: Getting Sharp Images With Depth of Field and Hyperfocal Distance
Step 3: Add Additional Filters
After you have the composition and sharpness of the image worked out and get a baseline of your camera settings, you need to add any filters that you want to use (though, not the ND filter just yet).
The great thing about some filters and filter holders, like mine from NiSi, is that you can stack filters to get the perfect effects.
In the image above, for example, my baseline shot was way too bright along the horizon due to the setting sun.
So, I added a reverse graduated ND filter in the second slot of my filter holder, and took a second baseline image to check for sharpness, composition, and exposure, which helped control the level of exposure in the middle of the shot.
Learn More:
- Graduated Neutral Density Filters vs Solid Neutral Density Filters: Differences and When to Use Them
- How to Shoot Landscapes at Blue Hour
Step 4: Dial in the Long Exposure Settings & Add the ND Filter
At this point, you need to switch your camera to manual mode.
But before you do, be sure to write down the aperture and shutter speed settings that were used to take the baseline image in Step 3.
Then, once in manual mode, dial in the corresponding aperture and shutter speed.
At this point, you also need to set your focus to manual. This locks the focus that was set in the baseline image.
Next, add the ND filter to the filter holder, bearing in mind that it should be the closest filter to your lens.
If you recall from above, when I added my reverse graduated ND filter, I put it in the second slot, leaving the first slot nearest the lens available for the ND filter. Having this in the second slot is necessary as you will need to move it to match the horizon.
When deciding which neutral density filter to use, bear in mind that it's essentially a creative choice in that the more stops an ND filter has, the blurrier the motion will be.
In the image above, I used a NiSi 3-stop ND filter to get just the right level of blur, but in other situations, a different ND filter might have been more appropriate.
Understanding which ND filter to use will come with time, practice, and experimentation, so give a 3-stop filter a try, and if you want more movement, swap it out for a 6-stop filter, a 10-stop filter, and so on.
Editor's Tip: Neutral density filters are just the tip of the iceberg. Complete your kit with a versatile polarizing filter.
Step 5: Determine the New Shutter Speed
Now that you have your ND filter in place, you need to adjust the shutter speed to account for the reduced light that's entering the lens.
If you want, you can do the necessary math in your head by multiplying the shutter speed by a factor of two for every stop of the filter you're using.
So, if your shutter speed was 1/125 seconds for the baseline shot and you're using a 3-stop ND filter, your new shutter speed would be 1/30 seconds.
But, if you're like me and math isn't your thing, there's an app for that.
Shown above is a screenshot of my go-to long exposure app, Long Exposure Calcs. It's got calculators for everything from landscapes to fireworks to the Milky Way, and even helps you calculate exposure times when you stack multiple filters.
Learn More:
- Best Camera Settings for Landscape Photography
- The #1 Pro Landscape Photography Tip for Amazing Photos
And That's It!
As noted earlier, mastering long exposures requires a good amount of practice and experimentation.
Of course, being equipped with the right gear - a solid tripod, a camera remote, and, of course, awesome filters - you'll have a leg up and be more apt to take breathtaking images like the ones shown throughout this article.
Just as an aside, I've been using NiSi filters for a few months now, and I can't tell you how pleased I am with these things.
They're rock-solid in terms of optical quality and construction and give you results that are simply impossible to get with cheap filters.
Head over to NiSi's website to see their selection of filters and to learn more about how lens filters can have a positive impact on your photography.