Variable ND Filters – How, Why and When to Use Them For Video and Photography

Hi, this is Jay P. Morgan. Today on The Slanted Lens we’re going to take a look at ND filters. How you set them up and why you use them. But first, our segment today is sponsored by Nisi Optics. They make great filters. But let’s get to why you use an ND filter. Because you want your video to look like this. Not something like this. This looks terrible. This looks cinematic and isolates your subject from the background. This is so busy and really confuses the viewer. This looks very artistic. It looks like the really good high-end film you’ve been watching all your life. This looks like bad video from the 70s, cheap and low budget. Everything was in focus in the 70s, except for all the people who were on drugs. They probably don’t remember though.

Remember that videography or film is about directing the viewer’s attention to what you want them to see. That’s why you cut in for close-ups. Look at this. I want you to see it. That’s why we go to really blurry backgrounds. We’re going, look at these two that are arguing, I want you to see them. It’s about directing the viewer’s eye to what you want them to see and not being distracted by something going on in the background that doesn’t strengthen our message. That’s distracting. I’m glad I’ve got a variable ND on so I can get rid of that and keep the background nice and simple regardless of what’s going on back there.

So how do we set this up. Well, the Sunny 16 rule tells us that outside in direct sun it’s f/16 and the shutter matches your ISO. So, at 100 iso it’s f/16 at 100 ISO at 1/100th of a second. But in video you can’t shoot 1/100th of a second. You’ve got to be at twice your frame rate. So, 24 frames means you’re at 1/50th or 1/60th of a second. That means you’re at f/22 at 100 ISO. Most cameras are not going to give you a lower ISO setting than 100. That means everything is in focus. So how do we combat that? The only thing we can do is reduce the amount of light that’s coming into the lens. Thus, an ND filter. Cinema cameras have built-in NDs you can change internally in the camera. But DSLR or mirrorless cameras do not. So, the only way to handle this situation is to add a circular or a square ND filter to the front of the lens. That’s how we’re going to control the light that comes into the camera.

Here’s why it needs to be a variable ND. Because you’re moving around. You’re shooting here, you’re in backlight, you’re in front light, you’re at f/22, you’re at f11, you’re moving all the time. You want to be able to quickly change and kill the light depending on the situation you’re in. So, you’re in the constant state of motion. That’s why you want a variable ND so you can change it and shoot and move, change it, and shoot and move. That’s why a variable ND works. Stop it!

We want f/2.8 in every situation we’re in and it’s changing constantly. Just the time it’s taken us to shoot this segment it’s changed throughout the entire day. So, we’re having to change our exposure and change and vary the ND that’s on our camera. So, what do I use? I use the Nisi 1-5 Stop Variable True Color ND Filter. I really like the Nisi 1-5 Stop Variable True Color ND Filter for several reasons. One, it’s optical glass. It’s made for sharpness. It’s not going to degrade your image. Next, it’s color neutral. In that entire variable spectrum, it’s not going to change the color of the footage at all. It’s going to be a true color through all that variation from one to five stops. Also, the front filter size is larger than the millimeters that you purchase so you’re not going to get any vignetting. Except for the 95 and it’s a true 95. I can use them for video and photography. So, it really applies to just about everything that I shoot.

Because I have a variety of lenses, I always buy my filters in 82mm because it matches my largest lens size. But now I can use step down rings to be able to adapt it to my smaller lenses. And that makes it so one filter will work with everything that I own.

So why do I use a 1-5 and not a 5-9. I like the quality of 1-5. I feel like they have great quality, and they don’t cross hatch. It’s really my favorite filter to go to. So, here’s a 1-5 it’s at f/5.6 which is great. I’m getting much shallower depth of field in the background but it’s still not as nice as f/2.8. So, I’ve got to add more ND to this. I will then add a 3 or 6 stop fixed ND filter depending on how bright the sun is where we’re working. I use a Nisi Pro Nano. Those are great fixed ND filters. It just gives me the ability to work in different lighting situations. I’ll stack those on. If it’s a very bright day, I’ll use a 6 stop plus my 1-5. If it’s a darker day or it’s getting towards the end of day, I’ll go to that 3 stop on the 1-5. And then when it gets really towards the end of the day, I go back to the 1-5. It just gives me options to work in any lighting situation quickly to be able to make the changes and get great shots. I love that setup. That’s my go-to setup when I’m doing video anywhere and I’m shooting outside kind of run and gun.

For photography we use an ND filter for a totally different reason. I use my variable 1-5 or the 3 or 6 or stack sometimes all of them to be able to give the illusion of motion. I want to slow my shutter speed down so I can blur the cars that are going by. I want to do a time lapse so that everyone is blurring in each image. So, I want long shutters like 30 seconds or 15 seconds. You know, sometimes just a second. It depends on what I’m doing. But that’s what you do with an ND filter. Using an ND filter allows you to blur the water so it looks fluid. It looks so beautiful in a landscape image. So, in landscape really, ND filters are a great addition to anyone’s landscape photography kit.

So, in conclusion I will thank Nisi Optics for providing us with our filters that we used here today. But as you can see ND filters have a variety of hats that they wear. They do a lot of different things. See what I did there, huh, huh. They do a variety of different things on set. Everything from shooting your video, running and gunning with that variable ND, to long exposure for still photography. They really are an integral part of a good professional workflow for photography and video.

So, I hope you enjoyed this lesson. So, leave us some comments below and keep those cameras rollin’ and keep on clickin’!