When Should You Use an ND Filter: Tips for Photographers and Videographers
Before buying my Sony a7S III camera for video, I had never bought any kind of filter before for my photography. When I started filming video content outdoors, I decided to invest in an ND filter that would be useful for both videography and photography.
In this blog post, I’m going to talk about ND filters and how it can be an essential tool for any photographer or videographer.
What Is An ND Filter
An ND filter (or Neutral Density Filter) is a filter that lowers the amount of light that goes into your lens. If you’re in a situation where you need to avoid overexposing your shot and you’re not able to do so with the settings from the exposure triangle (shutter speed, aperture, and ISO), then an ND filter might be a good choice to fix the situation.
There are various types of ND filters that can adjust your exposure by a certain number of stops. For example, an ND8 filter will lower the exposure of your image by three stops. An ND16 filter will lower the exposure of your image by 6 stops. The further you go up in numbers, the stronger the filter is in blocking light.
Here are some examples of when I would use an ND filter:
PROPERLY EXPOSING VIDEO IN CAMERA WITH ND FILTERS
As I mentioned, an ND filter was one of the first accessories I bought when I received my Sony a7S III. As someone who works outdoors and on-location, I don’t have a lot of control when it comes to lighting. When I’m filming video with my Sony a7S III, I will almost always use an ND filter (except for when I’m filming at night).
I keep my ISO as low as possible and adjust my shutter speed based on the frame rate I’m filming in. While I can adjust my aperture to lower the exposure of the scene, I prefer to have as much control over my camera settings as possible in order to get an intentional result. Sometimes even if I adjust my aperture to a narrow f/16, the video scene might still be too overexposed if I’m filming during the day.
Using an ND filter allows me to adjust the video while I’m shooting and not in post. Having too much of an overexposed image in the raw file will cause your scene to lose detail that you might not be able to get back.
Although it’s not something I use very often, I also have a variety of ND filters for my DJI Osmo Action 3 camera. When filming POV footage throughout the day, having different ND filters is definitely a helpful tool to keep a scene properly exposed without having to worry about the settings.
The raw (not color graded) screenshots above were taken with the same camera settings on the Sony a7S III and with the same lighting. The photo on the left is without the ND filter and the photo on the right is with the ND16 filter added on the camera lens.
Adding the ND filter brings back the details in the clouds and restores the natural color of the sky and water that you would not see originally because of overexposure.
LONG EXPOSURE PHOTOGRAPHY WITH ND FILTERS
Admittedly, I don’t really use ND filters for photography because I don’t often do long exposures for my images. And in the times that I do, I usually photograph at sunset or at night when I don’t need to use an ND filter.
However, I think it’s important to know that ND filters can be a useful tool for those who might need to lower their exposure in an image and your camera settings might not give you the desired result.
One common example of long exposure photography is slowing down the shutter speed to where you freeze the movement of the water. Just as I mentioned in the previous example, you can use a narrow aperture to lower the exposure, but I would recommend using an ND filter so that you can get creative with your camera settings if necessary.
STEP-UP RINGS FOR ND FILTERS
Before buying an ND filter, it’s important to consider the thread size of your ND filter and if it will fit with the diameter of your lens.
For example, I have an ND16 filter with an 82mm thread size. This fits with the Sony 24-70mm f/2.8 G-Master lens, which also has a filter diameter of 82mm. However, if I wanted to use the 82mm ND16 filter with my Sigma 85mm f/1.4 DG DN ART lens (which has a 77mm filter size), then I would need to use a step-up ring in order to fit the filter onto the lens.
Final Words
As a travel photographer and videographer, I always make sure to bring my ND16 filter. In my trip to Japan and Germany, I had the filter on my Sony G-Master lens for pretty much the entire trip (except during nights). Weather and lighting conditions outdoor can change pretty quickly and being able to adapt quickly is one of the most important factors in getting consistent quality photo and video content.
I invested in the Polarpro ND16 filter and after years of having the filter, I am more than happy to keep using it for all of my work. But there are plenty of filter options for you to explore. My advice would be to consider where and when you often shoot. If I had to buy one type of filter, I would get an ND16 or ND32 filter since they are pretty middle-of-the-road when it comes to the strength of filter options.
I have been able to use the ND16 filter without struggle, but if you shoot in bright daylight and are trying to stick with a low aperture, you’ll likely want to consider getting a stronger ND filter.
I hope you found this blog helpful. Thank you for reading and until next time.
