I was recently asked by a fellow photographer how I approach long exposure photography. When I sat down to think about it I decided that it is actually quite complicated and that the best thing to do was to write it down so that I didn’t leave out anything important.
What is long exposure photography?
Typically a long exposure is when you aim to use a relatively slow shutter speed in order to blur movement.
In landscape photography the most common use for long exposure photography is to blur movement in water. This might be to smooth out the ripples on the surface of a lake or to add an ethereal look to a waterfall.
Long exposure photography is becoming more and more popular and is a handy technique for any photographer to master.
What will you need?
Long exposures work best when the stationary objects are pin sharp whilst the moving objects are blurred. As exposure times can often run into the minutes a tripod is absolutely essential to avoid unintentional blur through camera shake.
You will also need to be able to control the shutter speed so will also need a camera that allows you to set the exposure and focus manually.
Often it can be difficult to slow the shutter speed enough to produce the desired effect so neutral density filters will come in very handy. ND filters act like a pair of sunglasses to reduce the amount of light that reaches a cameras sensor therefore increasing the time the shutter must remain open in order to correctly expose the image.
ND filters are rated by the number of stops they increase the exposure time. I typically carry 2 ND filters:
- A Lee Filters Little Stopper which increases exposure times by 6 stops pushing a shutter speed of 1 second up to 60 seconds.
- A Lee Filters Big Stopper which increases exposure times by 10 stops pushing a shutter speed of 1 second up to 16 minutes!
A remote shutter release that you can use to trip the shutter without touching the camera, again to minimise camera shake.
Finally taking long exposures using a digital camera can drain the battery so having a few spare batteries is probably a good idea.
Step by Step Guide
As I have already said long exposure photography can be quite complicated but if you follow this step by step guide you won’t go far wrong.
- Set up your camera on the tripod and compose your image as you would normally.
- Switch the camera to manual mode and select an appropriate aperture. As with any landscape photograph I typically start with f/11.
- Focus the camera. If you use autofocus remember to turn it off once the camera is correctly focused to avoid it attempting to refocus when you go to take the shot.
- Set the shutter speed needed to correctly expose the image. This is relatively straight forward with live view but you can always take a test shot to check your exposure.
- Make a note of shutter speed that you set.
- Attach your ND filter.
- Increase your shutter speed by the required number of stops to correctly exposure the image. Lee Filters provides a handy app for your phone that will do this for you.
- On some cameras the maximum shutter speed that you can set is 30 seconds. If you you need a longer shutter speed you will have to switch to bulb mode and time the exposure manually.
- If you are using a DSLR camera remember to cover the eye piece while doing long exposures to avoid light leaking into the pentaprism and spoiling your images. I usually just use the cloth that I use to clean my filters.
- Use the remote shutter release to take the shot. If you are in bulb mode you would typically fire it once to open the shutter and again to close it.
So, there you have it. It does take a little while to get the hang of long exposure photography but with a bit of practice it will soon become second nature.