Capturing movement in a still image is an art form that breathes life into photographs. One of the most effective tools in achieving this dynamic look is the Neutral Density (ND) filter. ND filters, essentially sunglasses for your camera, allow photographers to manage the amount of light entering the lens without affecting the color of the image. This capability is particularly useful when aiming to create motion blur, a technique that conveys speed and motion by blurring moving elements while keeping stationary objects sharp. Here’s a friendly guide to help you master motion blur using ND filters, just as if we were swapping tips over a casual lunch.
How to Use ND Filters for Motion Blur Video
The Equipment and Settings
(Click here to view a larger version!)
- Nikon D300
- Nikon 16-85mm f/3.5-5.6 DX @ 16mm
- Induro Tripod & RRS Ballhead
- 2 sec @ f/13 & ISO 100
- 6-stop Cokin ND filter
- Sigma EX Circular Polarizer
- Manual Exposure, Manual WB, RAW
The Shooting Conditions
You have a lot of different options when it comes to creating motion blur in bright sunlight. Firstly of course you want to stop down your aperture as much as you can afford to, without your images getting too soft due to diffraction. (f/22 is usually a bad idea, on most lenses and most cameras) And even at f/16, the sunny sixteen rule dictates that if your ISO is 100, your shutter speed is 1/100 sec. Unless this train was a bullet train going full speed, motion blur at 1/100 sec would be very minimal. So your next step is to darken the image overall using filters. For this particular image I used both an ND (Neutal Density) and a Circular Polarizer, however if you wish you can simply use an ND filter.
What about ISO “LO”?
ISO LO should be avoided if you have bright highlights in your photograph. I narrowly escaped blowing out my highlights in this image, because the Nikon D300’s native ISO is 200. If my image had been just 1/2 a stop brighter, this highlight would have been badly posterized:
So be careful with going into ISO LO when you are trying to maximize your shutter blur in bright sun.
What about variable ND filters?
Variable ND filters are awesome, if you can afford one. They usually run $100-$300, which is only a bargain if you plan to do a LOT of slow-motion shooting. If you are a more casual photographer, start with a Circular Polarizer filter and an affordable 3-6 stop ND filter, and try to get ones that have a thin profile in case you need to stack them.
Stacking Filters?
Usually, stacking filters is not advisable on lenses wider than about 24mm equivalent. However especially if your lens has smaller filter threads than 82mm or 77mm, you may just want to buy the largest size you need (82mm or 77mm) …and then use a filter thread adapter. For example many older wide angle Nikon lenses have 52mm or 55mm threads; if you get an adapter for 77mm filters then you can easily stack filters without any vignetting!
Understanding Motion Blur
Before diving into ND filters, let’s clarify what motion blur is. Imagine capturing a bustling city street; the stationary elements like buildings are sharp, while cars and pedestrians are blurred, showing their movement. This effect makes your photos feel alive, adding a sense of motion and energy.
Choosing the Right ND Filter
ND filters come in various strengths, indicated by their optical density or the f-stop reduction they provide. The higher the number, the less light they allow through. For motion blur, you’ll typically use a 3-stop to 10-stop ND filter depending on the light conditions and the effect you’re aiming for.
Camera Settings for Motion Blur
With your ND filter attached, it’s time to adjust your camera settings. You’ll be working primarily with slower shutter speeds, ranging from 1/15th of a second to several seconds or even minutes, depending on the light and desired effect. A slower shutter speed lets moving subjects blur while keeping the rest of your image crisp.
Composing Your Shot
Composition plays a crucial role in motion blur photography. Look for scenes where the movement contrasts with still elements. Bridges with flowing water, streets with moving cars, or forests with swaying trees can serve as perfect subjects. Remember, the goal is to guide the viewer’s eye through the image using motion.
FAQs
- Can I use ND filters on any camera? Yes, ND filters are available for all types of cameras, including DSLRs, mirrorless, and even some compact cameras. The key is to get the correct size for your lens.
- How do I know which ND filter to use? It depends on the lighting conditions and the effect you’re aiming for. A good rule of thumb is to start with a 3-stop ND filter for slight motion blur in bright conditions and adjust from there.
- Can motion blur be achieved without an ND filter? Yes, but ND filters give you more control over the extent of the blur and allow you to use slower shutter speeds even in bright daylight.
Capturing motion blur with ND filters can elevate your photography, adding a dynamic and dramatic element to your images. Like all photography techniques, it requires practice and experimentation. So grab your camera and an ND filter, and start exploring the moving world through your lens. Remember, photography is as much about enjoying the process as it is about the final image. Happy shooting!
