Most photographers are familiar with using a neutral density filter to create dreamy, long exposure photographs, but should you use a neutral density filter when shooting time-lapses too? In today's video, I explore why using a 10-stop ND filter might be perfect for more than just still photography.
A week ago, I released a video on how to use a 15-stop neutral density filter to remove people from your scene and create dramatic moving clouds in your landscape photos. The filter I used was the ND100k filter by Polar Pro, which allowed me to capture the longest exposure I have ever taken at 16 minutes. The company also sent us a few other filters, including their ND1000PL, which is a 10-stop neutral density filter with a circular polarizer attached to it. While this 10-stop filter isn't nearly as extreme as the 15-stop filter I used to create the photograph of downtown Charleston, it might be more suitable for other applications like time-lapse photography.
If you've ever watched any of our Fstoppers tutorials with Mike Kelley, Elia Locardi, or Joey Wright, you know we like to take a lot of time-lapses for both our behind the scenes series and for the lessons themselves. There are a lot of ways to create time-lapses, with the easiest method being shooting video and speed-ramping it in Adobe Premiere. The problem with this method is when shooting video, you are forced to set your camera's shutter at 1/25th of a second or faster. This forces you to capture every frame of video nice and sharp with very little motion blur. However, if you create your timelapses with still photos, you can easily set your shutter between 1/2 a second all the way up to minutes to create very unique motion effects.
For us, the most ideal shutter length for time-lapse photography is right around 2 seconds. This is long enough to blur most people, water, and traffic while still keeping your total time-lapse capture time within a reasonable time of 30 minutes or less. With a strong 10 or 15-stop neutral density filter, you can easily create single exposures of 10 seconds up to a full minute for some dramatic effects, but if you want a final time-lapse that is at least 10 seconds, you are going to have to stand next to your tripod for 40 minutes if not hours.
If you want to know an easy way to figure out how long your camera needs to take photos in order to create a usable time-lapse when using longer shutter speeds, here is a simple equation to memorize.
(Shutter speed x 24 frames per second x total seconds of final time-lapse) / 60 seconds
This will tell you the total number of minutes your camera will need to take photos in order to get a final time-lapse at the desired length. Keep in mind, you may want to add a full second to your shutter speed to account for any blackout time when the shutter and mirror are flipping up. Also, make sure you do not add any extra intervals in-between each shot, because that will not only increase your overall shooting time, but it will also introduce large gaps in-between each frame, which will not play back as smoothly compared to if each shot was taken consecutively.
As you can see in the video above, the difference between using a fast shutter and a long shutter is pretty dramatic. Like all genres of photography, how you create your own time-lapses is an artistic choice, and there is no absolute right or wrong way to choose your settings, but personally I do like the longer shutter speeds, because they add a smoother motion to the final presentation. Keep in mind, you will probably only need a neutral density filter when shooting time-lapses during the day since dusk and night exposures will probably already require a longer shutter speed to capture the scene. Below is a final light trail photo I created using these filters after my daylight time-lapse was completed.
If you are interested in getting your own Polar Pro 15 or 10-stop neutral density filter, you might want to check out the Polar Pro Trade-In Program where you can save up to $40 on a new filter when you mail in your old filter. You can also find a variety of other filter densities and ring diameters over at B&H Photo if you need something a little less extreme for video or photography. One final tip, you might want to buy the largest filter you might ever need, like an 82mm filter, and then buy a few step-down adapters so you can use one single filter on a variety of lenses. Most of our professional DSLR lenses are 77mm and 82mm, but all of our Panasonic GH5 lenses are 58mm. Since we have only purchased 82mm filters, we can use one single filter on all of our lenses without having to buy multiple filters for every different filter ring size.