Introducing Long Exposure Photography
Here is another article from Dynamic Range, the magazine I started and hardly anyone purchased, lol. I though some of you might be like this one.
Introducing Long Exposure Photography
Have you looked at photos of beautiful beaches where the water seems very calm and smooth? Perhaps you have seen architectural images of giant skyscrapers and the clouds are all blurred? Night photos that have a lot of colour and depth to them? Or maybe you have seen photos of
streets where the cars are so blurred that there are only the trails of where the lights were?
If you have, then you have been looking at long exposure photographs; a form of photography that has become very popular in recent years. There has been a growth in the number of photographers who are experimenting with this technique and it can seem like a complicated process, but, really, it isn’t very hard at all.
What is long exposure photography?
Put simply, it is any photography that requires you to use a tripod. Typically, you can hand hold a camera at around 1/100 of a second. Of course that is all dependent on the lens you are using and the focal length of it, but, as an average, around that long. If you want to do images that are longer than what you can hand hold then you need to have the camera on something that is sturdy, like a tripod.
When the camera goes on the tripod, you are ready for long exposures.
Different types of long exposures
Usually when someone says long exposure photography, people tend to think about filters and using them to get very long exposures, but that isn’t always the case. Night photography and Astrophotography are popular forms.
You can take night photos with any camera, but automatic cameras are never going to give the rich detail and colours that a good camera on a tripod with a longer exposure will give you.
Taking photos at night is no different to shooting during the day, except it takes longer and you need to use a tripod. When taking photos at night, the camera needs to be put on a tripod or a solid surface because it would be impossible to hand hold. The longest shutter speed cameras tend to have is 30 seconds which is often long enough for a night photo in the city. Though it is possible to take longer exposures as well if you use a timer of some sort and put your shutter in bulb mode.
Astrophotography, while also night photography, is done to photograph the stars in the sky. Photographers who are trying to photograph the milky way or star trails need to do long exposures. Both require the use of tripods and remote shutter releases. The exposures can be anything from 30 second, to minutes, or even hours.
Long Exposures with filters
A very popular form of long exposure photography is the use of special filters that help facilitate longer shutter speeds. Neutral Density filters, or ND filters have a neutral colour tone, meaning that when you use them the filter shouldn’t alter the colour of your image or give you any colour cast. The Density refers to how dark they are. The darker the filter, the longer the exposure.
Equipment needed for long exposure photography
While you don’t need a lot of equipment, there are some fairly essential items for long exposure photography.
Camera – You need a camera that will allow you to use manual modes as well as the priority settings, like aperture and shutter. However, for nearly all long exposures you need to have your camera on Manual, so it is important that yours allows you to use that. You also need to have a shutter speed called Bulb which will allow you to keep the shutter open for as long as you need.
Tripod – This is essential. As stated earlier you really one to get long exposures. If you are going to do very long ones, for example, up to ten minutes then a sturdy tripod is recommended. The best advice I hear from other photographers about purchasing a tripod is to get the best you can afford. Get the heaviest and tallest one you can. It is not something you will ever regret. You don’t want your exposures ruined because as soon as there is a slight breeze the tripod sways in it.
Remote Shutter Release – This is a device that allows you to take longer photos than 30 seconds. They are often called Intervalometers as well. They allow you to set the camera up to do the times that you want. They often have timers as well so you don’t need to watch the clock to get the exposure you need.
Neutral Density Filters – You need one or more of these if you want to do long exposures during the day. They come in various stops which will give you different results The most common long exposure filter is a ten stop.
What is a stop?
Stops are measurements of time. If you have ten stops and then do nine stops, then you are halving the amount of light, for example, ten seconds is then five seconds. If you increase it by one stop then you are doubling the amount of light.
For example, if your shutter speed is 1/60 of a second, then if you increase it by one stop, your new shutter speed will be 1/30 of second. However, if you are decreasing by a stop your new shutter speed will be 1/120 of a second.
Your filters work in the same way. The light is doubled until the correct exposure is worked out. There is no doubt that it is quite complicated, but luckily there are apps for your phone out there that take away the mathematics for you. For Android phones, a good one is Exposure Calculator and it is free. For iPhone check out the Apple Store for Long Exposure Calculators.
Shutter speed is not the only consideration, you also have to take into consideration aperture and ISO. As with any exposure in photography, the three have to work together to help create a well exposed image.
It isn’t uncommon to put the ISO down as low as possible and to make your aperture as small as it will go to help give the image a very long exposure. It is good to know how low your ISO will go; most cameras will go down to 100 or 200. The same goes with your aperture. On some lenses it might only go to f/22, while others might go to f/45.
For night and astrophotography, filters are not necessary. Usually the fact that it is dark is enough. By putting your shutter speed on bulb and using an ntervalometer, you can get two or three minute exposures in a city. However, if you are out in the countryside on a moonless night, you could conceivably get exposures of anything up to a few hours. It isn’t really recommended, but it is possible
When to use Neutral Density Filters
These are primarily used during daylight hours. They help to give you the longest exposure necessary to get the desired effect that you wouldn’t be able to get otherwise.
If you were at the beach and it was during the day, your camera would not be able to give you a long exposure. They aren’t designed to do that. You would need to use a ND filter.
The filters are very good for giving you a smooth water look or blurred clouds at any time of the day. Even on days when the sun is very bright you can put on a filter and do a long exposure.
This is why the filters come in different densities. If it is early morning or late evening and it is getting dark, you might only need a two or three stop filter. That is certainly the case for doing waterfalls. Often they are in canyons or deep ravines and, while it is dark, with no filter you can’t get that silky water look, but if you put on a three stop ND filter then you can get an exposure of several seconds which will help you get that effect.
If you are at the beach taking photos, then it can be a lot harder and you will need a much denser filter. Somewhere around a 10 stop is what most photographers prefer to use to get a longer exposure. Though, if it is really bright you might want to try a 16 stop. The latter filter will give you minutes even on bright sunny days.
Long exposure isn’t as complicated as it sounds, but if you love that serene, smooth water look or the blurred clouds then you will love doing them. Start planning how you can go and take some photos either at night or during the day with some filters.