How to Use a Variable ND Filter for Videos
In this video we will be learning how to use a Variable Neutral Density (ND) Filter to shoot videos.
ND Filters can be very useful in shooting videos because they allow you to get a shallow depth of field even in situations where there is a lot of ambient light. This is because, unlike photography, in videography, it’s not as convenient to cut down light by using a faster shutter speed, since shutter speed has an impact on how to the video looks.
Therefore, if you want to use a shallow depth of field to get a blurred background, using a variable ND filter will help you to cut down light so you can use a wider aperture. Here is the video:
This video is from our Videography for Beginners course, which has 35 videos and 4.5 hours of content. You can access the full course via Udemy, using the link below:
Videography for Beginners Course
Video Summary
This video tutorial demonstrates how to use a Variable ND Filter to maintain professional video settings while shooting in bright outdoor conditions.
The Challenge: Overexposure in Outdoor Video
When shooting video at a standard 24 FPS, your shutter speed should ideally be locked at 1/50s to maintain natural motion blur [02:08]. However, if you also want a shallow depth of field (e.g., f/1.8) to blur the background in broad daylight, too much light enters the camera, resulting in an Overexposed image [04:40].
The Solution: Variable ND Filter
A Variable Neutral Density (ND) filter acts like “sunglasses for your lens” [06:26]. It allows you to reduce the amount of light entering the camera without changing your shutter speed or aperture.
- How it Works: The filter features a rotating ring that you can turn to increase or decrease the darkening effect [06:56].
- Variable vs. Fixed: Unlike fixed ND filters, which have a set strength, a variable ND allows you to fine-tune the exposure directly from the lens, which is essential for videography where settings are often restricted [07:34].
- Application: Attach the filter and rotate the ring until the exposure meter is centered or the image looks correctly exposed to your eye [09:23].
Why Not Just Increase Shutter Speed?
While you could cut light by increasing your shutter speed (e.g., 1/100s or 1/1000s), doing so creates a “robotic” or “choppy” movement because it removes the natural motion blur that human eyes expect [11:47]. The video compares 24 FPS (1/50s) and 50 FPS (1/100s) to show that the slower shutter speed looks much more natural [11:29].
