So before we can figure out what ND filter we need there are two questions we need to answer first.
I have a few tips on the bottom of this page to help you pick the right one.
Yes there are two different physical types so maybe check that out also.
2.-Do you want to take 30-second exposures or 1 or 2-second exposures?
There are obviously a lot of different exposure options between the two but this is aimed at people starting out with ND filters.
To help answer this let’s just presume for now you are photographing seascapes, rivers, waterfalls or cloud movement. As these are the most popular Long Exposure images.
Before you actually try taking Long Exposure images I have a blog post here on Long Exposure Photography and the settings you need to take the images, a lot of people make a few very simple mistakes so please go have a read of it. Could be the best 8 mins you have spent in a long time.
The below shots will help you decide on the specific style of Long Exposures that you want to start with.
The photograph directly below was a 30-second exposure, as you can see it smoothens out the water completely and creates this milky soft effect in the water. This works well in waterfalls, rivers and clouds too. Usually, you would be using something like a 10-stop ND filter to achieve this but it all depends on the light levels at the time.
The shot below was a one-second exposure. It retains the texture of the main sea body and highlights movement nicely. Usually, you would be using a 4 or six-stop filter to capture this image. Again depending on the light levels at the time.
My go to filter kit is the Elia Locardi filter kit from Formatt Hitech which has a 10-stop filter, 4-stop filter, filter holder, polarizing filter and 3 stop Graduated filter included in the kit making it perfect for starting out. Filter kits workout a lot cheaper than buying filters separately. I have a complete review of The Elia Locardi kit here.
10% off Formatt Hitech filters worldwide with discount code…
I normally suggest clients go out and take photographs of a place they want to capture (that’s nearby) at the time or lighting conditions you want to capture it in. When you go home check your camera settings and see what your shutter speed was for the photograph. With apps like ND Expert on your phone, tablet or computer, you can work out what ND filter you would need to take the Long Exposure photograph you are looking for.
So how exactly does it work?
So you go out and take a photograph in your spot in the lighting conditions you want and you are now home sitting in front of your computer. Then follow these simple steps
- Open your photo in your editing app or just check your photos details, you should see your shutter speed here. Write it down or remember it. For this example let’s say it was 1/60th of a second.
- Open the ND Expert app by clicking here. You can download the app also and use it on your phone. It’s really very handy.
- Input the shutter speed into the Exposure time, so set it to 1/60th for this example. In our example this is the shutter speed your camera used to correctly expose the image and is a very important detail.
4. Your next step is to change the ND-filter setting. So if you change it to say a 10-stop filter you notice now that you get an exposure time now of just over 17 seconds.
6. If you wanted a one second exposure you just try different ND-filters until you hit the one second mark. In this instance it would be a six stop filter.
So that’s how we can use our existing photographs to work out what filter we need.
Now I am guessing there are a few people saying but hey this doesn’t tell me how to shoot cloud movement or what ND filter I need for them…
That’s very true, my trick for you there is to go to your spot and pop your camera on a tripod and take a photograph then 10 seconds later take another one. Have a look at the two images and see how far the clouds have moved between the two exposures. If they are moving too much then try 5 seconds, if they are too little try 20 seconds between shots. This will tell you how long the exposure needs to be. Now isn’t that a handy little cheat 🙂
I really hope this helps you and if you have any questions then please feel free to ask me here.
I also have A comprehensive guide to seascape photography blog post if you are interested in it.
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See you out there,
Kieran Hayes Landscape Photography Ireland What ND filter do you need and how to work it out. Clonakilty Cork Co. Cork Ireland Kieran Hayes Photography 5 5 0 5 5 0 43 1st of April 2020 https://www.landscapephotographyireland.com/blog/what-nd-filter-do-i-need