7 Common Questions About Long Exposure Photography Answered

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Long exposure photography offers a who new way of seeing the world around you. Once you get started you may become totally hooked. It isn’t a cheap form of photography, to begin with, but once those initial costs are taken care of, you can photograph as much as you want, providing you take care of your gear.

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The filter and holder on a lens. There is also a graduated filter on this one.

If you are new to long exposure photography it can seem like a very confusing process to get your head around. Ultimately it does become much easier, but there are some common questions that most people first ask. You might have some yourself. Over the years I’ve been teaching long exposure photography, here are the seven most common questions that I get.

1 – What is long exposure photography?

Typically, long exposure usually refers to any photography that requires a tripod. For most photos, you can hand hold the camera. However, there will always be places that are too dark and in order to get a good image you will have to sacrifice ISO and turn it up a lot. That will enable you to get a fast enough shutter speed to capture the image.

Increasing your ISO does introduce noise and for many situations, it is not good to do that. This is when you should put your camera on a tripod. When you do that, you are starting to do long exposures.

Typically, you would do long exposures for night photography or if you are using special filters. However, when most people talk about long exposure photography they are usually referring to the use of ND filters that block many stops of light which will allow you to keep the shutter open for a long time.

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Shelly Beach in Sorrento, this was taken with the Firecrest 16-stop ND filter for 6 minutes.

2 – What are ND filters?

There are many different types of filters used for photography, especially when people were using film. However, the most common type for digital photography is a Neutral Density filter or ND filter. This filter sits in front of your lens and is used to block out some of the light. They vary in density, and the darker the filter, the longer the exposure you can achieve.

They are called neutral density as they are color neutral (no tint). Many filters do give you a colour cast, the most common being magenta. However, good filters should not affect the color in the final image at all.

The density refers to how dark it is, though this is often called stops. A 10-stop filter is much darker than a 6-stop. A 16-stop ND filter is very dark and you can’t even see through it with your eye.

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Dragons Head at No 16 Beach in Rye. 25 seconds with the 10-stop ND Filter.

3 – What is a stop?

The stops can be an indicator of how dark a filter is, or what its density is, but it usually refers to time. The higher the number of stops a filter has, the longer the exposure will need to be. A stop is a measurement of time. Put simply, it means you are either halving or doubling the amount, depending on whether you are increasing or decreasing the number of stops.

For example, if you are using a 10-stop ND filter and the exposure time is one minute, but you decide you want to go to an 11-stop filter, then you need to double the time, so the exposure would be two minutes. However, if you went down a stop to 9, then the time would be halved and become 30 seconds. If you decreased another to an 8-stop filter, then you would halve it again, 15 seconds.

This is a very simple way of looking at it. If you want more information then take a look at this article written by Jim Hamel on What is a Stop? The Common Currency of Exposure Explained.

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Bolte Bridge in Melbourne, using the Firecrest 16-stop ND filter for four minutes.

4 – How do you figure out the exposure time needed?

With experience, you do start to get a feeling for which filter to use for specific conditions, and for how long. That doesn’t help you when you are first starting, but thankfully there are apps available that will help you take the guess work out of it.

You can get the apps for both Apple and Android phones. Just look up Long Exposure Calculator and you will find them. They will help you work out how long to expose for, according to the stop number of your filter. The calculator takes into consideration your ISO, your shutter speed, and aperture when the filter is off.

I have an android phone and I use an app called Exposure Calculator. I have been told the app Longtime Exposure Calculator for iPhones  is also very good.

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Hopetoun Falls using a 6-stop ND Filter, 13-second exposure.

5 – What subjects are good for long exposures?

There are three main subjects that people use long exposures for; water, clouds, and people. Basically, ND filters can be used for anything that moves where you want to get a blurred effect.

Water

Perhaps the most popular subject for long exposure photography is water. Using the filters can give that smooth water look. Though, they can be good for waterfalls and help to get that marshmallow or silky look. The filters are often used to show how water moves on beaches, capturing the movement of the water as it rolls in and out.

Clouds

The filters can be used to capture the movement of the clouds as they move through the sky. Many people also do long exposures with architecture having blurred clouds behind the buildings. City scenes are very popular as the effect gives the scene a quiet, empty feel.

People

To help get that isolated feeling long exposures can empty the scene of people. It works really well unless people are walking straight towards you or they stop and stand in the same place for a long period. If you give it less time you can get a blurred effect so that people or cars look like ghosts in your images.

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A city scene that has removed the people. It was taken with the Firecrest 16-stop ND filter for 3 and a half minutes.

6 – Square or round filters?

There is a big difference of opinion with this one.

Round filters

Round filters screw onto the end of your lens like many traditional others like UV filters. You order the size according to the size of the thread of your lens. It is the same size as your lens cap (look on the back of the cap).

However, if you want to use more than one lens for long exposures then, in theory, you would need to buy filters for all them. You can, however, get step-up rings, so it is best to buy a filter for the biggest thread size lens. For example, my largest is a 77mm, and I then get step-up rings for the smaller ones. So if you also have a 62mm lens, then you can get a ring that will go from 62 to 77mm. You can then use the one filter for both lenses.

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A round screw in 10-stop ND Filter. The color is solid.

The disadvantage is that every time you recompose your shot, you have to unscrew the filter and then screw it back on. Some people don’t mind this, but others find it too time-consuming.

Square filters

The square filters are more expensive as you have to also buy a holder for them. But you can get different adaptor rings for the different size lenses. The advantage of this system is that you can remove the holder easily each time you want to recompose your image, then put it back on quickly. It is an easier system in that respect, though it is a bit more work when you are setting it up and packing it away.

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A square 10-stop ND filter, again the color is solid.

There are a lot of companies that make filters for both systems up to 10 stops, but for darker density ones you have to get square. Many of the top filter companies only offer square filters. I use Formatt Hitech and they make round filters up to 10-stops, but their Firecrest 13 and 16 ND filters are square. Whereas, I believe, the Lee Filters are all square.

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Filter holder, the square filters slide into it.

7 – Cheap or expensive filters?

There is an easy answer to this question. You get what you pay for and the cheap ones are nearly always a mistake. They often have a really bad color cast, magenta, and can give you a lot more work to do in post-processing. If you are working in black and white, there isn’t a problem, but for color, it is a headache that most regret.

The top quality filters are expensive. But they will last you for years and if you love long exposure photography they are a purchase you won’t regret. The best filter to start with is the 10-stop. It is the most versatile and you can add more filters as your confidence grows and you have more money. I started with the 10-stop, now I have a 16, a 13, a 6, and a 3-stop. I can also stack them which gives me even more choices as well and doesn’t reduce image quality.

Many filter companies also provide packs that will provide you with everything you need. Formatt Hitech, for example, have the Joel Tjintjelaar Signature Edition and it has the 3, 6 and 10-stop ND filters, plus everything else you need to get started.

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A pier down at Sorrento. Two filters were stacked for this, a 10 and a 3-stop. The exposure was 3 minutes.

The magic of long exposures

There is something quite magical about long exposures and once you start to do them it is hard to look at water or clouds the same way again. A whole new way of expressing yourself is opened up. Many think it is complicated, but it isn’t really.  Take a chance and give it a try. Let me know how you go.

Please put your questions in the comments section below and share your long exposure images with us as well.

Read more from our Tips & Tutorials category

Leanne Cole is a fine art photographer based in Melbourne, Australia. She loves Melbourne and photographing it, along with other parts of the state. She likes doing architectural and environmental photography. You can find her on her website or on Instagram.

  • Mark A Pijaszek

    Great stuff here…thank you!!

  • Alvie Morris

    I bought an inexpensive filter that I had never heard of. The brand is called Cacagoo. I know, weird name. I believe they’re made in China, but I only paid about $20 for 77mm and it works brilliantly!https://uploads.disquscdn.com/images/71d48f4950563127bf7433b28170d8d40fd45f1c84f4791649ecc287769dbbd4.jpg

  • Alvie Morris

    The image isn’t perfect, I didn’t have a tripod and had to brace the camera against a rock, so it slipped ever so slightly, creating a blur around the edges of the rocks.

  • drdroad

    A common use of long exposure is a city scene where you want the headlights/taillights to stream https://uploads.disquscdn.com/images/0103a026c76fb2075521e2cf70a32543b90a49b8fac1b30ce4712c4ef8f0ff1a.jpg through the scene.

  • You’re welcome, glad you enjoyed it, thanks Mark.

  • If you managed to get an inexpensive filter and it works, that is great. My experience hasn’t been so good. I end up with very magenta photos, especially for very long exposures. Thanks for sharing your image, next time you might want to try a tripod, just a suggestion. Good luck.

  • Yes, I do that a lot too, though I tend to refer to it more as night photography, which is still long exposures as well. Thanks for sharing your image, it looks great.

  • Bob Bevan Smith

    In the days of film, there was a phenomenon called reciprocity failure. Essential, that says that if you use a very long exposure (say 30 seconds or more), you have to more than double the time for each extra stop down of light (so not going to 60 seconds, but perhaps 65 or more). Does anyone know if there is a similar effect with the sensors in digital cameras?
    Also, with digital sensors, the longer the exposure, the more noise appears, even at lower ISO settings. Many astronomers cool their cameras to try to counteract this.

  • Ardelle

    Thank you for this very informative tutorial. I wished I knew what the conditions were that made you choose your filters and exposure time in these wonderful photos. I also wondered why you chose to stack a 10 and a 3 filter instead of using the 13 you had. I got a full set of filters with my Canon but have not attempted to use any of them, nor have I done any tripod work…. yet. Thank you again for this tutorial.

  • I haven’t heard of that Bob, though I never tried long exposures when I was doing film. So, sorry, I don’t if you do or not.
    You do get more noise and the hotter it is the worse. If you take really long exposures you can get what they call hot pixels, so white spots or spots of bright colours. Have to be very careful. Cooling or making sure camera isn’t in the sun certainly helps.

  • A lot of it is experience Ardelle and just trial and error. Sometimes I think it is not too bright and put on the 10 stop, only to realise I need the 16, so I experiment, same with time. Though I am getting a lot better at judging now. I can often know exactly what filter I need and roughly how much time to expose it. I think it is just about getting out there and trying it. If your photo comes out black, you need to give it more time, if it comes out white you need to give it less.
    I stacked them because when I took the photos I didn’t, at that time, have the 13. It is good to have the option of stacking them. Some brands you can’t and you get terrible colour casts, but have never found that with the Formatt Hitech ones. Thanks Ardelle.

  • David

    Hi Leanne, I use Hoya HD round filters with Cokin grad ND if needed. For dawn shoots, I start with just the grad ND and when the sun comes up, I then add a 6 stop round filter to smooth the water. Using liveview, I can still compose without taking the 6 stop round filter off. A different story for my 10 stop or if I stack my 6 and 10 stop together. 1 point to mention is that manual focus can be needed (focus with no filter and then change to manual) as most AF systems can’t cope with the low light. 3 minutes/16 stop (stacked round ND) shot attached for example. Really need a swivel screen or remote display for these ones 🙂
    https://uploads.disquscdn.com/images/70fc0da8ca38374453bd21b204394464ef01d51a9ec054c7dee33d80f0af5ebd.jpg https://www.flickr.com/photos/davidmarriottsydney/21598991266/

  • Guruprasad Baba

    Hi sir great information,I couldn’t afford expensive nd filters so I bought Rangers cokin filters set from US through Amazon but it’s not of good quality, can I buy variable nd filters(eg tiffens or hoya) which is a cheaper option, please guide, my widest lens is Tamron 24-70mmIS at 82mm

  • Hi David, I think if you are going to convert your images to black and white then you have more options for filters. The 6 stop is good like that, you can see through it. Yes, this article wasn’t really a description for how to do long exposures, but focusing is very different. I focus my image without the filter, then put it onto manual and then put the filter on. In the end we all do things differently in some ways. Thanks for sharing your image.

  • The wider the lens the more expensive they get. I don’t know Tiffen filters, but Hoya can be quite good. I started with a ND400 from them, it’s 9 stops.It is hard when you can’t afford good filters, but you can always work up to them. Good luck.

  • Alvie Morris

    You might want to try this filter. Haven’t tried it myself because I found one even more inexpensive (unfortunately the one I have maxes out at 77mm). But I’ve heard good things.
    http://www.itsjustlight.com/reviews/ice-10-stop-neutral-density-nd1000-filter-review/

  • Dave_TX

    The pixel cells on the sensor are electrically leaky. The higher the pixel count for a given size sensor the smaller the pixel cells are. Additionally, the cell walls are thinner. Electrons migrate through the walls. Cooling helps a lot by slowing down the electrons. Throwing some shade on the camera is a start.
    One way to avoid the problem is to take a lot of relatively shorter exposures and add them together to form a composite exposure.

  • Alvie Morris

    Actually I was wrong, the filter I got does come in 82mm size. I highly recommend it! With shipping included it costs $25 for the 82mm. Here’s the link:
    https://www.wish.com/m/c/5666814974c8b62093b23c29

  • ernldo

    All, even expensive ND filters create a color cast. ALL do, and its easy to fix in post….

  • I don’t know, I use the Formatt Hitech ones and I don’t think they do at all. I never have to correct the colour. Then again, you could say the same about cameras as well, they all favour certain colours.

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