Key camera settings for long exposure photography
Here is a summary of the most important camera settings that you will use in long exposure photography:
Shooting Mode
Use Manual Mode (M) to have complete control over your shutter speed, aperture and ISO settings.
Alternatively, you can use Shutter Priority Mode (S or Tv) so you can control shutter speed while the camera adjusts aperture and ISO automatically. This works in many situations but gives you less control for difficult situations.
Shutter Speed
This is obviously the key setting for long exposure photography. A slow (long) shutter speed allows the camera to capture motion over time.
We will look at typical shutter speeds later, but to cover the range of situations where you might use long exposure photography, you will need to know how to dial in, and get a good exposure with, anything from 1/3 of a second to 30 seconds using your camera's in-built timer, as well as how to do shutter speeds longer than 30 seconds using 'Bulb' mode (since on most cameras this requires a slightly different technique).
Aperture (f-stop)
A narrow aperture (high f-number) helps to cut down the amount of light entering the lens and prevent overexposure during long exposures, especially in bright conditions, and in some situations may mitigate the need for the use of ND filters.
It's usual to start with an aperture of f/8 to f/16. A mid-range aperture helps keep more of the scene in focus due to greater depth of field, but also gives scope to open or close the aperture if you need to in order to modify the shutter speed.
ISO
It's always best to use the lowest ISO possible to avoid introducing noise, which can become more noticeable in long exposures.
I normally use ISO 100 (or lower if your camera supports it) for all long exposures (although night sky photography is a special case where it is necessary to increase ISO).
Focus
Focus on a specific point, then switch to manual focus so this focal plane is locked in. This is especially important if you need to use ND filters, since camera focus systems often struggle to gain focus through dark filters.
Stabilization
Turn off in-camera image stabilization when your camera is on a tripod if you can, since counter-intuitively, these systems can cause vibrations that affect sharpness in longer exposures.
Taking a long exposure photo; a step by step guide
Now that you have selected an appropriate subject (somewhere where you want to blur motion), you have all the right kit (a camera with manual settings, a tripod, a remote release and optionally ND filters) then it's time to set up and take your shot.
1. Set up your camera
Fix your camera to your tripod, make sure it is securely attached and ensure all parts of the tripod are tight to prevent any drift during long exposures. Be aware that if you are on the soft sand of a beach, your tripod might sink in, so find a firm surface!
Turn off image stabilisation (if you have it) in your camera menu.
Preferably set your camera to shoot in RAW file format (rather than JPEG) for maximum flexibility in post-processing. This format preserves more data than JPEG, especially in low-light situations.
Switch your camera to Manual Mode (M): This gives you full control over exposure settings like shutter speed, aperture, and ISO.
2. Select your shutter speed
The shutter speed determines how long the camera’s sensor is exposed to light, and how much moving subjects will be blurred. The exact choice of shutter speed will depend on what is happening in the scene and what your creative intent is. E.g. slightly blurring a waterfall needs a shutter speed of around 0.5 seconds; creating a flat milky looking see by blurring all of the waves takes around 30 seconds; blurring the movement of clouds normally takes a minute or more.
Note on Bulb mode: Note that on most cameras, if you wish to use a shutter speed greater than 30 seconds you will need to use 'Bulb' mode (normally the next selection once you move past 30 seconds). In Bulb mode, the shutter will stay open as long as you keep the shutter depressed; so if you wish to do this, you will have to use some sort of timer to open and shut the shutter (since using your finger will move the camera!). There are a range of options available, such as remote shutter releases with timers, or camera apps that use InfraRed of Bluetooth to operate the shutter.
3. Set your aperture and ISO
Aperture (f-stop): Start with a medium to small aperture (f/8 to f/16) for a larger depth of field. However, depending on the amount if light in your scene, you may need to open or close the aperture in the next step in order to ensure a good overall exposure.
ISO: Keep ISO low (ISO 100 or lower if your camera has it) to reduce noise. Long exposures tend to introduce noise, so lower ISO settings will help maintain image quality. The only exception is for night sky photography where you can't use very long shutter speeds without causing star trails (unless this is your intention!) and so have to use higher ISO settings to get a good exposure.
4. Adjust your settings until you have a good overall exposure
You will need to know how to use your camera's light meter (usually an arrow that points between -3 for underexposed and +3 for overexposed) to assess when you have a good overall exposure. If your shot is underexposed, you can increase the shutter speed (understanding that this will change the amount of blur!), open the aperture to let more light in, or increase the ISO, or a combination of all three. Do this until the light meter arrow is around the 'zero' mark, as this shows you have a good overall exposure. See this blog on how to nail your exposure.
Note on ND filters: If you cannot dial in a long enough shutter speed without over exposing (your light meter shows +3), and you have tried shutting down the aperture and reducing the ISO, then you will need an ND filter (essentially sunglasses for your camera) to allow you to extend the shutter speed without over exposing. Simply add the ND filter (best done AFTER you have locked the focus - see below) and then increase the shutter speed as required. For more details on ND filters see this blog.
5. Compose the Shot
Now you have your camera settings sorted, it's time to think about composing your shot. In doing so, don't forget to consider following the composition rules.
6. Focus & lock it
Autofocus can struggle in low light or when using an ND filter, so you can either:
- Find an area of strong contrast (e.g. a streetlight) and focus on that (as focus systems generally work on contrast). See this blog on how to control where you focus.
- Use Manual focus (where you focus by manually turning the focus ring on your lens until the scene is in focus)
Whichever method you use, you should then lock your focus (turning your lens switch to manual focus will effectively do this). This prevents any accidental shifts in focus, and ensures your scene is in focus before you add any ND filters.
7. Take the photo
Use a remote shutter release or a timer: This will prevent camera shake. If you don’t have a remote, set your camera’s timer to a 2 or 10-second delay so you don't move the camera whilst taking the shot.
Check the histogram: After taking a shot, review the histogram to ensure that your exposure is well-balanced. The histogram helps avoid blown-out highlights or underexposed shadows.
Check the image: Check if you have captured the scene in the way you wanted to, if not then try again!
Final Words
Long exposure photography is a great way to get creative with your camera, and hopefully this step by step guide will help to get you started. Next week, in the final blog of this series, we'll build on this general guide to help you understand some specific situations such as photographing waterfalls, flat seas and car light trails.
Want to improve your photography skills?
Don't forget that if you want some direct help with your photography, I offer a range of 1-2-1 photography courses for Devon based folks. If you're not nearby then I also offer residential weekends for beginners or improving photographers.
About me
I first got into photography after walking the beautiful South West Coast Path: I was so disappointed that my photos didn't do justice to the beautiful coastal scenery that I decided to walk all 630 miles all over again, but this time to also teach myself photography along the way!
A few years later and I find myself as a professional photographer, widely published and with landscape photos which have won national awards. But I do much more than landscapes, providing photography training to businesses & individuals on how to take beautiful photographs, and providing professional photography services to businesses across the South West. My commercial specialisms are property photography, business photography, people photography & aerial (drone) photography.
I’m also an author with a number of published books and I give regular talks about my passion for photography, and for Devon, to camera clubs and other groups.
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