It’s safe to say that you don’t always carry a neutral density filter (ND filter) with you… Heck, some of you may not even know what one is or own one (check out my camera lens filter guide if you’re unsure what a neutral density filter is). That’s alright, neutral density filters are key to differentiating your photography from amateurs photography but that is a different article for a different day. Today I want to talk to you about how to get similar results to shooting with a neutral density filter without actually using a neutral density filter.
What are the results of using a neutral density filter?
Neutral density filters come in various flavors, you can get graduated nd filters, graduated colored ND filters, different strength ND filters depending on what your needs are. In the simplest form a ND filter reduces the amount of light that enters your camera. This is advantageous if your shooting in bright situations but you’d like to use a wide aperture for creative reasons but your shutter speed can’t go any faster. Attaching the ND filter to your camera will reduce the light and allow you to use a wide aperture and a reasonable shutter speed.
Another more common use would be utilizing the ND filter to create dynamic imagery of moving water or clouds. Proper use of the ND filter can create moody and dynamic imagery. Using the ND filter is a simple way to improve your photography and capture unique images.
How to get ND filter like results without a filter or Photochop
Being familiar with the relationship between shutter speed, ISO, and aperture can allow you to replicate long exposure photography without a neutral density filter in some cases. One of the most popular methods of long exposure photography is the blurring of water, creating photographs of swift moving water that looks like silk instead of water. Getting similar results without a filter is possible once you know how to master shutter speed, ISO, and your aperture.
Shutter speed. What causes the water to look smooth as silk is that the shutter speed is staying open long enough to capture the movement of water. The speed of the water will determine the ideal shutter speed for blurring, the slower the movement of the water the slower the shutter speed you’ll need.
Aperture. If you don’t have the luxury of a ND filter then you’ll have to find another way to allow your camera to reduce its shutter speed without over exposing the scene… Enter the shutter speed/aperture relationship. Every adjustment you make to shutter speed can be compensated for with your aperture and vice versa. Want to slow down your shutter speed? Adjust your aperture to a smaller setting (higher f/number).
* You run the risk of diffraction when you use very narrow aperture but it’s a trade-off. Diffraction, in a nut shell, is the softening of an image due to a higher f/number (narrower aperture)… I’d recommend reading in more detail about diffraction if you’re unsure what it is and how it impacts your photography. Check out my article Diffraction and Your Digital Photographs.
ISO. Increasing your ISO will increase your exposure so it makes sense that if you are trying to lower your shutter speed which also increases your exposure you’ll want to decrease your ISO. When attempting to replicate the ND filter without the filter you’ll want to use your cameras lowest ISO setting (you can use the low extension setting as well but be aware that you’ll actually reduce the image quality of your image slightly, read more on that here).
The image above was taken without a ND filter and my goal was to blur the water as if I was using one. I used the lowest native ISO setting on my camera (100) and then I adjusted my aperture to f/22 in order to reduce the amount of light coming into the camera. Next I was able to reduce my shutter speed to compensate for the higher aperture which resulted in a 1.2 second long shutter speed and my desired result. The grain you see in the image was added in post processing.
This technique is not meant to be your answer to long exposure photography, this is a technique you should keep in the back of your mind for the day that you break your ND filter or come across a scene that begs long exposure but your ND filter is elsewhere.