Thank you all for making it out to our long exposure meeting this past Thursday! If you missed the meeting or want to review what we talked about, here is a recap on the topic of long exposure.
To start off, a long exposure is essentially using more time to expose the photo more for than what one person can typically hold the camera steadily. Typical long exposure may take from 1/5 seconds to 25 seconds and it depends on the goal of the long exposure. This will allow more light coming into the camera and reach the sensor, and thus a brighter exposure; it will also result in a sharp contrast between the stationary and moving objects by creating motion blur. Finally, it can create many dramatic effects out of perfectly ordinary object which can help improve your photos. We will talk about three typical scenarios for why using long exposure is important.
ND filter example.
Before I (Wenjun Ning) start the three typical scenarios, I have to mention what is needed for long exposure. Because how long the exposure typically takes, we cannot hand-hold the camera and will need a way to fix the camera in place. The solution is to use a tripod; however, you can improvise by just placing the camera on the ground (or other firm object). You will also need a Neutral Density filter if there is too much ambient light like during the daytime. This filter will reduce the amount of light passing through it, effectively making the exposure darker, thus balancing the brighter exposure brought by longer exposure time and will give us a correct exposure in the end. An intervalometer and shutter trigger might also be helpful, though not always necessary. They can conveniently help us set up a time interval to take each exposure (e.g. for circular star trail), or prevent shutter shake (which is undesirable for a long exposure as it may create unwanted trailing) respectively. Remember that a dark ND filter may disable auto focus because there may not be enough light to focus with. So focus before you put a ND filter on as auto focus might bring you hassle later on.
Waterfall photo example. Photo by Wenjun Ning.
Now for the scenarios. The first scenario for long exposure is to create trailing effects. It is important to notice that with extended exposure time, light reflected by moving objects is still being captured by the camera sensor; this creates the trailing effect. A typical example would be a waterfall. See photo above that I took where the flowing water creates trails as it moves downstream, while the rocks are kept sharp as they are stationary. Waterfalls are a typical example of trailing. Keep in mind that every object will provide trailing effect if they move at appropriate speed relative to shutter time. For example, Niagara Falls might only need about 1 second to create beautiful trailing, while some smaller fall at creeks may take you 2 second or more to create continuous and complete trailing. You have to adjust the exposure time accordingly to the speed of the object.
Light painting OK from our club astrophotography trip. Photo by Wenjun Ning.
Light painting in the dark - keep in mind that long exposure allows more light to come into the camera, so it performs excellently in dark conditions. While exposing, one can move light source and it will leave a trail on sensor. This allows us to paint various of things at night. This exposure above that I took was 6 seconds.
Long exposure of clouds and stars. Photo by Wenjun Ning.
Emphasizing motion and contrasting the environment - the cloud is moving at a fast speed, while the stars are moving at incredibly slow speed. The tree is almost stationary. This type of trailing emphasize motion and is mostly seen on car advertisement photo. This exposure took 25 seconds.
Long exposure photo on a bullet train. Photo by Wenjun Ning.
Trailing the background - anything can be “trailed” and there is no limitation. Camera is placed on a bullet train, moving at 300 km/h (186.4 mph), and a mere 1 second exposure is plenty to capture the change of views outside the train.
Now we learned about the trailing of long exposure, we can talk about how to smoothen the surface of the water. By using a dark ND filter and having extremely long exposure and hopefully not very much wind and waves, we can effectively smoothen the wave on a body of water, and sometimes even create a mirroring effect. This is one of the extreme case of trailing, what essentially happens is that the slight movement of waves on the surface of the water is blurred out over a long period of time, while what is stationary - reflections on the water and what is underneath water, stays in place and gets sharper and sharper over the exposure time. This can be used for many purposes, such as preparing a photo ready for post-processing for better mirroring effect, or to show the audience what is underneath the water.
Two photos above that I took shows the difference between a regular exposure (1/160s) and a long exposure (25s). The slight change in color in long exposure is brought by a Circular Polarizer, which will allow us to see more of what is underneath the water, but it does nothing to smoothen the water. A ND 1000 filter is used for long exposure to reduce the total amount of light coming into the camera. It effectively reduced the light to 0.1% of its original intensity, thus allowing a shutter speed of about 10 stops longer.
Another example of the smoothing effect is provided below.
15 second long exposure with the beautiful reflection. Photo by Wenjun Ning.
Milky way photo with reflection. Photo by Wenjun Ning.
Long exposure for water smoothing works at night as well. I will still encourage the use of long exposures at night because it can help us to see what we cannot see with our own eyes (in addition to being necessary most of the time so that the camera can capture enough light due to being dark).
Keep in mind that it is required to be near the shore of lake or have a relatively small angle of incidence for reflection to happen on water. Calmer wind is also necessary. A completely still lake may provide a good reflection without a need of long exposure, however, long exposure is still recommended.
The last scenario of when to use long exposure that we will discuss is crowd removing. When properly used in an ideal setting, we can completely remove unwanted crowd at a popular destination for people. Because the crowd are constantly moving while all the building and floor are stationary, long exposure can help us to capture the stationary object clearly while ignoring the majority of affects by crowd in the picture. Simply set up the tripod and prepare a ND1000, just take a few photos (typically around 25s) and enjoy the crowdless scenery.
You may notice the first picture have almost no crowd while the right one has a lot. This is due to the fact that the left photo took 25 seconds while the right one took 2 seconds to expose. Because crowds are constantly moving, this will allow us to take a photo of a “ghostly bridge” while it actually have many people passing through it.
Star trails photo. Photo by Sidath Karunaratne.
Finally I will briefly mention stacking. Stacking is very typical for long exposure photo as they further enhance trailing in the photo and smoothing the photo even more. I would always recommend stacking and it can improve your photos in some scenarios. Here are some photos stacked by Sid which allows him to create dramatic effect. To stack stars like this, you can simply change the blending mode to “lighten” in Photoshop. To stack types of other photos to create the effect of a longer exposure, you can create a smart object within Photoshop containing all the individual photos, and then change the smart object’s stack mode to “mean” which will average the photos together.
San Francisco Skyline Fireworks. Photo by Devansh Rathi.
Overall, try out long exposures whenever you can. It will definitely provide a different perspective to the scenery that you are looking at! Learn to set up the exposure time based on your lighting and environment is crucial to long exposure and not missing the perfect moment (such as fireworks and focus before hand).
Once again, thank you for coming to the meeting and I hope you enjoyed this weekly blog on long exposure!! If you took any cool photos from that light painting session, we would love to see them and reshare them. Here are some photos taken by Sid from our meeting and our members practicing some light painting.
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