We received a question from a reader and thought we might give a little introduction to neutral density filters here for anyone else that’s struggling with long exposure photography…

Could you do something on long exposure? I went out yesterday with a 10 stop ND and tried it. My pictures were either too light even after stopping down the aperture and a low ISO. The other thing, even though on a sturdy tripod, most of them were too blurry. I was shooting in Manual and used the live view to focus. What gives? ―Jenny Waller

There are so many things that we try in photography that make us all think, “what gives?” I’m not sure what subject you were trying to photograph, Jenny, but hopefully this will help!

What are ND Filters?

A neutral density – also known as a ND filter – is a filter with a dark appearance that is used to even out the exposure of different elements in your photo, such a bright sky and a dark foreground. Since the filter stops the light from reaching the camera sensor, it allows the photographer to leave the shutter open for a longer period of time than would be possible without the filter.

ND Filters come in different levels of density that are supposed to be the equivalent of stops. When looking for a filter, you will see that they have numbers with decimals. If you’re not really sure what that means, here’s a quick reference guide to those numbers:

How do they affect a photo?

Although they are dark when you look at them, they do not change the color of the photo. Their main purpose is to block a large portion of the light that comes in through your lens from reaching your camera’s sensor. This allows you to leave the shutter open longer than you would normally be able to.

Nikon D600 | 42mm | f/22 | 15 sec | 100 ISO | -1 Exposure Bias

How do you use them?

ND filters might sound complicated, but they can be very easy to use with practice! First thing you’ll need to do is purchase a filter. If you’re not sure you want a 10-stop filter, another option is to get smaller stop filters that you can stack together. I purchased the 3 stop (0.9) and a 6 stop (1.8) that I use separately, as well as stacked together to achieve a 9 stop filter when needed.

Filters come in many different sizes to fit the end of your lens. I recommend getting the 77mm since as you upgrade lenses, this will be the size of most glass in your bag. If your current lenses are not 77mm, you can purchase an inexpensive set-up of step-down rings that will allow you to use them on all of your lenses. This will help you down the road instead of having to purchase additional filters. As with all things in photography, the more expensive the filter, the better the glass will be (worth the investment). I personally invested in the B+W filters. I wasn’t happy to spend approximately $100 on a filter, but still having that same filter years later makes me happy I purchased this one instead of several cheaper ones.

What situations are they most useful in?

ND filters work magic in waterscapes where you want to give the water a smooth and silky feel. This also has the same effect on clouds. My favorite time to use them is for waterfall shots!

Nikon D7000 | 18mm | f/8 | 1/3 sec | 100 ISO

Tips for success with ND filters

Since your shutter is open for a longer period of time, a sturdy tripod is essential. You’ll also want to make sure that you are on completely level ground so you don’t have to worry about your tripod moving accidentally on its own. It’s also a good idea to use a shutter release cable or remote release – the less contact you have with your camera the less chance of having camera shake affect your photo.

If you are using a 10 stop filter, first set your focus, then switch the focus on your lens to manual mode so it doesn’t change. Once the filter is on, you won’t be able to see through the viewfinder as the filter is very dark.

Nikon D7000 | 35mm | f/22 | 13 sec | 800 ISO | +2 Exp Bias

Hope this helps! I’m sure others of you have found many ways to use your ND filters… please leave a comment below to share your tips with us!