A popular style of photography at the moment involves long exposures which enable the photographer to capture a scene in a way that can't be seen normally. Clouds become streaky, flowing water becomes silky, waves on the surface of lakes or the sea are smoothed out, people walking through the scene disappear or become ghostly shadows of themselves.
This is an example of the type of effect that can be achieved at dawn or dusk where exposures can run into minutes
This shot was 136 seconds which smoothed out the water enabling much nicer reflections that the choppy harbour would normally have offered. This particular shot was taken at dusk, the light levels meant I could use a really long shutter speed to gather enough light to make the shot bright enough.
Shots like this can often be done without the need for specialist equipment, other than a camera, sturdy tripod and a cable release (to stop you shaking the camera when you release the shutter).
A tip I was given when I was just starting out in photography is that light and exposures can be likened to water filling a bucket. If water is flowing into the bucket it won't take long to fill, if there is only a dribble of water filling the bucket it will take ages to fill. Similarly in bright sun typical landscape exposures are in the region of a 100th of a second, at night you'll need much longer to get a bright exposure.
During daytime there is too much light about to allow long exposures without assistance from filters. What we need is a filter that reduces the amount of light coming into the camera so that it takes much longer to get the correct exposure. In the bucket of water analogy we need a lid with a small hole cut in it to slow down how quickly the bucket fills. In photography these filters are called Neutral Density or ND filters.
On this shot I used a relatively weak ND filter (3 stops, every stop doubles the shutter speed needed) to give just enough movement in the water that it didn't look completely silky, I wanted to capture the movement and energy of the waves.
This 3 stop ND filter gave me a shutter speed of of half a second instead of a 15th of a second which would have frozen the water much more.
If you want really long exposures in bright daylight then you'll need a much stronger ND filter, one that reduces the light coming into the camera even more.
This photo of the raging waters of the River Etive in Scotland was taken in broad, albeit cloudy, daylight.
This exposure took 67 seconds with a 10 stop filter which extends your shutter speed by 1000 times. Without the filter this shot would have only needed around a 15th of a second exposure which would have frozen the running water.
There are several brands of 10 stop ND filters on the market, the main brands being Hitech and the one I use, the Lee Big Stopper. If you're working to a really tight budget you can even use welding glass!
Using these filters takes a little bit of practice and organisation to get the best results, here is my workflow for working with long exposures;
1) Compose, get the shot looking right in the viewfinder, including what I want in the shot and, more often more importantly, excluding what I don't want in shot
2) Focus, then switch to manual focus
3) Meter, with both the camera's internal meter and an external spot meter
4) Expose for a standard shot
5) Apply ND grad filters as necessary to get the exposure right
6) Take a test shot at a short shutter speed
7) Examine the histogram on the short shot for blown highlights or blocked shadows
8) Adapt exposure according to step 7
9) Work out 10 stop shutter speed - various apps are available for smartphones to do this for you
10) Close viewfinder to stop light leaking in
11) Check AF on manual and IS/VR turned off
12) Slide 10 stop filter into position checking it covers the entire lens
13) Set the exposure up, either on bulb or with manual setting
14) Check mirror lockup is switched on
15) Lock mirror up, give it a second or two for any vibrations to die out
16) Set shutter with cable release, either one shot if it is on manual (eg less than 30 second exposure) or lock it off if on bulb.
17) Check top plate exposure timer and also chronograph for exposure time
18) Walk about, try and keep warm for up to 32 minutes!
19) Unlock shutter release when exposure time reached.
20) Review shot and reshoot as necessary (if I am doing a long exposure at dawn or dusk the exposure time is a bit hit and miss as the EV of the scene changes during the exposure).
If it has all worked correctly you'll get amazing effects that you just can't see with the naked eye, like this:
Have fun and feel free to get in touch if you have any queries or if I can help.