If you are on to photography, you’ve probably heard about ND Filter at least once.
ND Filter a.k.a Neutral Density Filter is commonly used by photographers who want to cut off or limit the extra light without reducing the aperture.
So, why would anyone ever want to cut off extra light using separate filters instead of just playing around with camera settings like ISO and Aperture?
There are situations which I’ll cover later, that need the use of ND Filters.
SO, in this article I’ll be explaining what ND filter is all about in the most simple and complete way.
If you are in hurry, here is the quick look of the article.
What is ND Filter?
ND is an acronym for Neutral – Density. It is a filter that is mounted over the lens to cut-off/reduce light during any kind of photography session where the lens gets more than enough light to expose the subject.
It usually reduces the wavelength intensity from light without making any changes to the color hue.
Making it more simple, take ND Filter as your sunglasses and take your Lens as an eye.
Why is it used?
Now, you know what ND Filter is, it is time to know why is it even used.
At this point, you may think what is the point of using ND Filter while you can easily reduce light by reducing aperture or ISO and increasing shutter speed through the camera settings.
While decreasing Aperture and ISO may work in some situations to cut off any light, doing it won’t help in every situation with a high amount of light.
For example, if you want to shoot an image with motion blur or any long exposure shot, you might want to set the shutter speed slow enough to make the desired effect work. But, slower shutter speed means more light hitting the sensor through the lens. If there is already a pretty good amount of light in the field you are shooting, you will end up over exposing the image.
In such case, applying the ND Filter to the lens will greatly help.The only use of ND Filter is to cut off any light to avoid overexposed image.
How does it work?
For this article, I’m not going through science of ND filters to know how it works. That’s surely for another article and is gonna be fun. Here I’ll explain how ND filters work in general. ND Filters are indexed by the amount of stops of shutter speed it plays with. Basically if you are shooting at shutter speed of 1/1000 using 2-stop ND Filter, the end photo will be as you’re shooting at 1/250 shutter speed.
For ease, visualize a sunny day, you’re surely wearing a pair of sunglasses. Wearing sunglasses reduces the amount of sunlight that hits your eyes, thus making it easy for eyes.
That is the same theory on how ND filters work. The thin dark filter cuts off a certain amount of light passing through it. And, there are varieties of ND filters with different density and mechanisms which I’ll get to in a second. All you’ve to understand is that denser the filter, more light it cuts off. Now, let’s move to its varieties.
Types of ND Filters:
There are some kinds of ND filters used according to situation and the intention. For example, imagine you’re shooting a sunset where there is enough light but also you want some motion blur, in such situation, a normal plain ND filter may not work. You may need a much denser and darker filter.
Thus, there are different kinds of ND filters available for Photography, I’ll explain about some major ones.
General ND Filters
As I said earlier, the ND Filter comes with the certain rating of the amount of shutter speed stops it’ll reduce. Generic ND filters are the ones that come with a fix amount of stop of shutter speed that it will play with.
Graduated ND Filters
This is a kind of ND filter which has a graduation from lighter to darker shade in its filter. It’s used whenever you might want to darken a portion of your frame like a landscape with a bright sky. This kind of ND Filter is preferred much in rectangular shape as that shape helps the graduation to work better.
Variable ND Filters
The name of this ND Filter pretty much defines its purpose. You can easily vary a density of your filter by rotating a ring around it. Simply, by rotating a ring, the darkness the filter can be tuned. This characteristic of Variable ND Filters makes it one of flexible choice for photographers.
How to use it?
Practically, you use ND Filters by mounting them to the lens. That is not a big deal.
But, determining your shutter speed after you mount the filter is a bit tricky. It is tricky but fairly not that tough, especially if you know the math behind it.
But, no worries, I’m here to explain.
Here’s what you need to understand.
You already know that an ND filter is indexed by the amount of ‘shutter speed stops’ it drops.
While using an ND filter, the normal shutter speed you would use to capture a shot would be different.
For example, you’re taking a shot of landscape and you’re using the shutter speed of, let’s say 1/125. If you’re using ND filter in this case you should tweak shutter speed according to your ND filter otherwise you might end up with a dark image.
How to buy it?
If you’re planning to buy an ND filter anytime soon, you must consider some aspects like the type of photography you do, how bright an area would be while shooting, etc.
If you’re an absolute beginner to long exposure photography, you must not go with high end filters that cost a lot.
Instead, go with cheaper and flexible alternatives like some affordable variable ND filters.
You might want to get a fixed ND filter that will always reduce light upto certain stops like 2 stops/5 stops or you might also love to get a variable ND filter that will allow you to reduce light according to the light situation you have or if you’re bit of amateur level, you might love to play around with graduated ND filters. The choice is yours.
Here I suggest some good and affordable ND filters out on the market.
Please note some ND filters are specific for particular brands and lenses. Before buying, look if the filter is compatible with the camera or the lens you have.
K&F CONCEPT 58MM Adjustable ND Filter
UURig Aluminum Rapid Camera Lens Universal ND Filter
K&F Concept 58mm Variable Neutral Density Filter
So that ‘s all about it. ND filters are life savers if you’re a long exposure freak and understanding them is necessary before using them.