In a previous ReelRebel episode on video lighting tips we taught you how you can utilize gels on your lights in order to keep your color temperature correct to get the best look for your shot. In this episode Stephen gives an overview of neutral density (ND) filters and gels for video - which are kinda like sunglasses for your DSLR camera or lighting rig and can help you better manage exposure in various lighting conditions.
The same way you need to ensure your color temperature is right to minimize color correction in post-production, you also need to make sure the lighting of your scene or parts of your scene are exposed correctly and not too bright. One way to compensate for lighting that's too bright is to use a ND gels and/or filters.
Neutral Density (ND) Filters and Gels for Video
Before I go into any of this, the truth is that no gel or filter can substitute for shooting at the right place and time to capture the most appropriate lighting. However, properly used, filters and gels can allow the the videographer to capture a scene that may be impossible to capture otherwise.
Lighting Neutral Density Gels
Most lighting gels are used for controlling color temperature - however, neutral density gels can be used to help change and control the intensity of the light.
Neutral density gels are most commonly available in grades:
- ND3 (0.3) - takes away 1 stop of light = -1 F-Stop
- ND6 (0.6) - takes away 2 stops of light = -2 F-Stop
- ND9 (0.9) - takes away 3 stops of light = -3 F-Stop
Essentially, the higher the number the darker the gel will be which in turn will cut back on the intensity of the light.
As an example, if you have a particular lamp that's putting out too much light relative to other lights, you can slap a ND gel on that light to even out your lighting set. Or, if you are shooting inside and too much light is coming through the window, you can put a neutral density gel on the window to cut down the intensity coming from that bright sunlight.
ND Filters for Video
While ND gels can be used on lights to control the intensity of a given light source, you can use ND filters on your camera itself to change the intensity (lessen) of the entire scene. For the most part, neutral density filters for DLSR camera lenses come in the same intensities as the gels, although there are other grades if you find you need them.
One of the things that determines your depth of field is your aperture and F-stop. When you close your aperture to bring down the brightness you start to deepen your depth of field and at the same time lose a lot of the artistic look that a shallow depth of field can provide. By placing an ND filer on your lens, you can maintain the shallow depth of field you may want for your shot by keeping your aperture open but not over-exposing the shot..
Graduated Neutral-Density Filters (Grads)
There are also graduated neutral density filters, aslo known as split neutral density filters, that will add a brightness and intensity on one side of the shot while tapering it off on the other. In general, if the scene that you're shooting has a contrast range that exceeds the dynamic range of your DSLR camera, then use of ND filters is a must. However, there are many times where you would choose to use them even when this is not the case.
Graduated ND filters really only work when there's a lineral transition between light and dark areas in the image. So, a good example of a use case would be a shot at the horizon whereby the sky is too bright when compared to the foreground.
You can purchase 1-stop, 2-stop, 3-stop graduated ND filters all the way up to a 5-stop filter.
Using the appropriate filters and gels can ensure a better looking video and as mentioned, limit your editing time in post-production.
QUESTION: What filters and gels do you use most often when shooting video?
View The Full Video Transcript:
Hey I’m Stephen Schweickart with this episode of Reel Rebel and today we’re going to show you another way to control your image with ND Filters.
The first video of our Advanced Lighting series taught you how to slap some gels on your lights and keep your color temperature in check. This time around you’ll be slapping even more gels on your lights to keep their intensity in check. Jeez, these lights sure take some policing to get right, eh? Anyway, we’re talking about ND or Neutral Density filters and their job is to keep parts of your scene, or your whole scene as we’ll get into later, from being too bright.
ND gels work a lot like color temperature gels in that you just clip them onto your lights for them to do their job, but obviously we’re dealing with brightness, not color, so they have very different functions. These gels are available most commonly in three grades, .3, .6 and .9, each getting darker as the number rises. So the higher the number, the more it’s going to knock down the intensity of the light. If your backlight is putting too harsh a rim on your talent, stick an ND on there to help bring it down a notch. Simple.
But what if your whole scene is too bright? Well there’s a solution for that too! And I don’t just mean that you need to suck less at lighting. That’s not doable. There are ND filters available that screw right onto the end of your lens bringing the brightness of your entire scene back from that “surface of the sun” look we’re trying to avoid. The ND lens filters come in the same intensities as the gels, though you can find different grades if you try.
Let’s look back on one of our old videos about depth of field. We tell you here that one of the factors that determine your depth of field is your aperture. So if you have to close down your aperture to knock down the brightness, you start to deepen your depth of field and lose that filmic look that blurring parts of your scene gives you. Sticking an ND filter on your lens saves you from having to do this and preserves that deliciously shallow depth of field all amateur movie makers, including you newbies are looking for.
If you want to get real fancy, you can even find gradient ND lens filters that start at a certain intensity on one side and taper off at the other. These are perfect for keeping your skies from being totally blown out when filming a landscape or any scene where you’re seeing a lot of this bright blue dome around the Earth. When it comes to exposure, the name of the game is CONTROL. If you can’t control your light, it will control you and let me tell you, it will NOT be gentle.
How about now that you’ve got all this fresh knowledge, you go ahead and control that cursor down here to the like button and then up to this massive subscribe button in front of me. Drop us a comment below and tell me how pretty I am.