ND Filters: Everything You Need to Know

ND Filters: Everything You Need to Know

ND filters have been a popular topic lately, so Action Photo School decided to share how we use them and what challenges we face while using them. Using ND filters for action sports sounds like a stupid idea.. doesn’t it? Why would you stop the light from hitting your sensor, when you are trying to freeze motion and get the highest shutter speed possible?

It isn’t a great idea, until you introduce a flash in the scene! Generally speaking ND filters have been popular among flash fanatics trying to overpower the sun. We’ve all seen these edgy great looking images, captured midday with a lot of flash power.


So now you’re thinking, “why not just stop down the lens?” and the answer is for shallow depth of field. Shallow depth of field is often an image characteristic of true professionals. It also helps you keep the subject separate from the surroundings.

You can always stop down the lens to f16, and get great images with a powerful enough flash, but you can’t do it so there is a pleasing bokeh behind your subject in bright midday light. That’s where ND filters come into play. You thread the filter on the front of the lens to bring the ambient exposure down. From our experience the best results are achieved when you underexpose the ambient light by 1-stop, but this is mostly a matter of taste.

Depending on the time of the day and the lighting situation you may need ND filter with a different light blocking power. They come in different varieties, ND2, ND4, ND8..ND512. The different ND filters are quantified by their optical density or equivalently their f-Stop reduction. ND2 = 1 stop of light reduction, ND4 = 2 stops, ND8 = 3 and so on. So what that means is that if you have an f/1.2 lens and you want to shoot midday portraits at f/1.2, you will have to use an ND filter with a high number or stack a couple of the smaller number filters on top of each other.

There are few things to keep in mind when choosing and using ND filters. First of all, by putting a dark filter on your lens, you will darken your viewfinder too, and if you stack a few of them together it could get really dark. Some cameras like the 5D mark II are going to have a harder time focusing with ND filters on the lens.


Second, make sure you don’t buy the cheapest EBay filters because they will downgrade the quality of your images. Why spend a ton of money for a nice camera and fast lens if you are going to put a piece of plastic in front of it all?

You can also find a single ND filter that has a rotatable ring allowing you to choose the density of the filter. These however, are pretty pricy, but they are very convenient.

When used with the built in TTL meter, the camera doesn’t need any adjustments. The camera will measure through the lens and give you the correct exposure. If you are using a light meter you will have to take in to consideration the amount of light that the filter blocks and add it to your exposure value.

You usually don’t want too shallow of a depth of field when shooting action sports, but if you get the focus right and combine it with shallow DOF, flash overpowering the sun, and an underexposed background you will get some “different” and pretty interesting results!

To conclude, we feel that ND Filters are not a must-have for action sports, but if you are looking for unique images with flash and shallow DOF, they are great to have. When it comes to portraits it is a matter of choice and style so give them a shot and see for yourself if they work!

Authors Connor Walberg and Daniel Milchev are both published professional action photographers, and together run Action Photo School. A website dedicated to teaching all aspects of action photography. Whether you’re an established action photographer, or just starting to shoot action, Action Photo School is the place for you!

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Some Older Comments

  • John Madden October 29, 2011 04:49 pm


    You're right an ND will effect both. But most cameras only sync with the flash at 1/200 or less. So, you can't use your flash at a faster shutter speeds in bright sunlight say at 1/500 even though it may be powerful enough to fill with. Putting on the ND helps get the shutter speed down into the sync range so you can use fill flash to brighten shadows caused by overhead sunlight.

  • juan October 29, 2011 05:58 am

    Great tip! Never thought of it. I have a ND filter and have never used it! Now I will!

  • renato molina October 28, 2011 04:50 pm

    Awesome. I was just about to throw my nd filters. The tip gave me an added incentive to experiment once more and discover new ways to use them.

  • Joao Luiz October 28, 2011 11:14 am

    ND filters, I made friends with them, and this is one of my favorite results: http://flic.kr/p/9KX25m
    But I confess I had never thought of using them for action shots. Since the lightest I have is an ND4, I will treat myself to an ND2 soon.
    Thank you!

  • Jake October 26, 2011 12:14 pm

    Neutral density filters allow you to use a slow shutter speed or a wide aperture in bright conditions. What I don't understand is the statement that an ND filter will help you overpower the sun with flash. Wouldn't the ND filter reduce the total exposure (sun and flash equally)?

  • Fuzzypiggy October 25, 2011 11:25 pm

    I almost always shoot with ND's fitted. I try to limit myself to a single ND if I can but sometimes you need a little more to drag out the exposure. I use grads more than anything else as I shoot landscapes first thing in the morning and as the sky is lighting faster than the land and you need the balance. I love using ND's as you say to get clarity and stop the highlights getting blown in harsh light.

    I use Lee Filters ND's as almost their entire range of ND sheets are hand-made ( seriously, check out Mike Browne's visit to the Lee Filters factory here in the UK ). Lee's have such wonderfully rich tones when you shoot through them, they really make sunrise/sunset landscapes shine.

    You can't beat the Lee Big Stopper, solid glass 10-stop ND superb for those coastal/streaked cloud shots.

  • ccting October 25, 2011 07:16 pm

    wow,, photography is $$$$$$$$$$$ you need to get powerfully speedlight + filters..

  • Erik Kerstenbeck October 25, 2011 11:01 am

    Wonderful article!

    I use a Signh-Ray variable ND. Sometimes the result has artifacts but in general is good...kinda pricey though!

    Here is a shot from Canada using this filter maxed out to smooth the Lake.


  • Ryan October 25, 2011 09:23 am

    Sweet! I never thought of doing this, but it makes perfect sense! I really enjoy the looks that I get when I tell people that I use ND filters at night...as you can imagine. But understanding the relationship between the tools available to you and the effect you want is really one of the main keys to successful shots. Here I took a ND filter to weed out all the passersby in downtown Chicago. The result? I was able to completely isolate my stationary subject w/o the need to clone out people in post processing!!!

  • Mark Finley October 25, 2011 09:03 am

    Far from everything we need to know, I use mine for shallow DOF portraits at day time and creating depth by capturing the clouds drifting over a scene, day or night.

  • JackRob October 25, 2011 07:49 am

    Thanks a lot for a whole load of information in a small package! This is honestly something I've never tried. Can I just ask another free info, as in a filter brand recommendation? Much appreciated....

  • Jason October 25, 2011 06:41 am

    whats a good affordable ND9 or which ever has the most stops reduced for a canon. By that i mean best quality because I definitely do not want to take a way from the quality of my L lenses. Also, shopping around I am finding that different manufacturers have different results per reviews on their ND9s. It seams that most of them are not getting the results buyers want when it comes to stopping down light. I do use flash and softboxes with people portraits but am planning to shoot more nature and landscapes in longer shutter time hence my need for the ND filter. So I need something that is more versatile without spending hundreds of dollars. Thanks!

  • Johnny Lightspeed October 25, 2011 04:11 am

    Scott, a lot of articles on here are from "guest contributors", so many times, the article will not contain the type of information that someone who writes for the site will include. I've seen plenty (a lot) of articles on here that purport to be articles but are really only basic introductory pieces that don't ever go into any detail. :/

  • Gnslngr45 October 25, 2011 03:07 am

    Totally agree with Scott.
    I have and use a circular polarizer which can make a huge difference, but need to get some ND filters as I love this look.



  • THE aSTIG @ CustomPinoyRides.com October 25, 2011 03:00 am

    Great concept! I also do action photography to but it's automotive-related.

    I do Car Photography for my website http://CustomPinoyRides.com

    Do you have examples where the same concept was used (ND Filter + Flash) but this time for panning shots or anything with motion blur? Perhaps using rear curtain sync or something? Or is it not possible? Thanks in advance!

  • Christine October 25, 2011 01:50 am

    LOVE THIS! I would never have thought of this. With 4 little boys, I'm just starting to tap into sports photography. What a great tip.

  • Scott October 25, 2011 01:41 am

    Interesting idea and great execution, but I feel like this article should be titled "ND filters for action shots" instead of "Everything You Need to Know".