So I was absolutely thrilled to see a photo of the falls on flickr a few years ago in which the water seemed to be cascading down the rocks in multiple streams of silky soft material. That was when my eyes opened to the power of the long exposure shot in converting an ordinary scene to one of extraordinary beauty.
Years went by, and I was in this wonderful place called Cherrapunjee on a holiday with my family. As is usual in the month of May, it had mostly rained throughout the day. The sky had cleared up a little while ago, treating us to the spectacle of a beautiful sunset, and now it was almost dark. For the first time, I had all the right equipment(decent camera, sturdy tripod) to try and get a good long exposure shot. So I plunked my tripod down right in the middle of a small stream, focused the camera on the water, held my breath, and clicked. And here’s what the result looked like - the first long exposure shot of my life!
Since then, I have lucky enough to get a number of opportunities to take a reasonable number of such shots. Along the way, I have bought a couple of filters and learnt some new things as well. So here’s what I have learnt so far.
For any long exposure photograph, the key objective is to ensure that you maximize the amount of time that the shutter stays open so that the movement melds into something smooth and flowing. So all our efforts have to be focused on getting the camera to deliver this.
As a starting point, I assume you have a decent camera in which you can control the shutter speed and exposure, but you don’t have any other specialized filters etc. Ideally you also have a decent tripod. If not, your camera needs to be placed on a solid surface before taking the shot. You have already located the object of your photographic affection – maybe a waterfall, maybe a small stream rushing by, or even waves dashing against rocks on a beach.
In order to get a long shutter speed of a few seconds or more, you would ideally need to shoot at times when the light is pretty low. The best times would be either at dawn or dusk, when there is just about enough light to illuminate the scene. To keep things simple, I prefer to keep the camera on aperture priority and let the shutter speed take care of itself. To ensure that the lens remains open for as long as possible, I would set the aperture to the minimum possible – f/22 or even f/32. One benefit of this level of aperture is that you get huge depth of field i.e. objects close to the lens as well as objects very far away will probably be in focus. One disadvantage of such a small apeture is that image distortions start creeping in. Based on the lens you are using, set it to whichever number works best for you.
The other factor you can control is the ISO. Set it as low as possible, say 100. You are basically reducing the camera’s sensitivity to light by doing so, and this will result in the camera keeping the lens open for longer to properly expose the scene.
Finally place the camera on a solid tripod or surface, focus, and click. Just one thing, since the exposure will be a long one, any shake of the camera needs to be avoided. One prudent thing to do to avoid shake while you are pressing the shutter would be to set the camera on its self-timer and click. To be even more careful and avoid the shake due to the “mirror slap” of SLRs, put your camera on “mirror up” mode and then take the photograph.
That, then, was the simplest way of getting these photographs. However, this needs the situation to be ideal - you need to have access to the location at exactly the right time to get the shot right. Here is a photograph I took where the shoot location was right in front of our hotel. Thanks to jet lag, I even managed to wake up at an unearthly hour to capture this shot without the use of any specialized equipment.
What do you do if you are visiting a place and are not able to be at the right location before sunrise or after sunset? Is there any chance of still getting those long exposure shots?
Well, yes. Provided, of course, that you are willing to invest in a very useful thing called a neutral density filter. So what is this magical piece of equipment? Simply put, it is like a sunglass for your lens. It is a grey coloured glass filter that fits in over your lens. Since it is dark, it cuts down the amount of light that reaches the sensor in the camera, so that the same scene will require a longer exposure time with such a filter compared to without.
Depending on how much light they cut off, there are various grades of neutral density filters available in the market. There is a standardized protocol for naming these filters – an ND.3 allows only 50% of the light to reach the sensor, an ND.6 filter allows only 25% , and so on. Depending on your needs and the price of the filter you could select any of the various options available.
I ended up buying the ND 3.0 filter from B+W, which is considered to be an “extreme” ND filter, since it allows only 0.01% of the available light to reach the sensor. The advantage of this is that I can use it even in bright sunlight to get long exposures. The disadvantage is that the glass is so dark that it is practically impossible to see anything through it while composing the shot, so one has to compose the shot and do the focusing first and then screw on the filter. This is what my ND filter looks like.
Sometimes, however, a simple ND filter may not be enough. For example, I was in Goa, trying to get some long exposure shots on the beach. Unfortunately I woke up a bit late (actually quite late, way past sunrise). Thanks to this, the sky was pretty bright though as a saving grace, it was cloudy. I spotted this nice looking log lying on the sand with the waves swirling all around. Due to the brightness of the sky, however, I was not able to get a long enough exposure to get the effect I wanted even after stopping down the aperture all the way. Luckily, I had just the solution with me - a graduated neutral density(GND) filter!
So what is this new creature? Well, it is like a normal neutral density filter, except that it is perfectly clear at one end and gradually gets darker and darker towards the other end. It is basically a rectangular piece of glass that is dark at one end and clear at the other. You need to buy a filter holder that matches the diameter of your lens & place the filter in front of your lens. I attached this filter, rotating it to ensure that the dark part covered the sky. Doing this cut down the light coming from the sky significantly, thus giving me the extra exposure time I needed to get the shot I wanted.
And here is that shot.
So in circumstances where one part of the scene is significantly brighter than the other, a GND filter can be used to cut down the light from the bright part of the scene, thus ensuring even exposure. Other than for long exposure shots, you can use GND filters to ensure that details of the sky(clouds etc.) are not burnt out when shooting landscapes on bright sunlit days.
Some additional points about GND filters.
· Like ND filters, different grades of GND filters are available.
· There are circular and rectangular graduated ND filters. If you are ever to buy one, do not go for the circular one as it provides very little flexibility for adjustment. This is because once it is screwed in front of the lens, its position is fixed.
· There are also “hard” and “soft” GND filters. In the hard filter, there is a sharp demarcation between the clear and shaded portions, while the transition is very gradual in the soft filters. With the hard filter you have to be more careful about its position so that the dark line disappears into the horizon and does not appear as a line in your photograph.
To summarize, if you are able to take the trouble to get to the right spot in time, you can still get great long exposure shots without using any special filter. However, having either of these filters can help you get some shots that would not be possible otherwise. Take a look at the image below. To my mind, the scene looks like rocky cliffs surrounded by mist. In reality, the shot is that of moss covered rocks on the sea shore. Thanks to the long exposure that my ND filter enabled, the flow of the water has been smoothed out to such an extent that it looks like a mist. This is despite the fact that the sun was shining pretty brightly by then, as you can see from the bright glow of the sun on the top of the photograph.
I hope this note has been useful. Hope you shoot a lot of beautiful long exposure images & look forward to seeing them if you connect with me on fb or flickr. All the best!