Long Exposure know how

As a result of numerous questions and requests I have decided to post a few photography tips.


The first topic is Long Exposure, it's really quite simple.
Always remember that a photograph is just captured light. Each photograph needs to be correctly exposed (to have enough light, neither too much nor too little).
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A long exposure shot is simply one where the camera absorbs the image (light) for longer this then creates a blurred effect on moving objects like cars, stars or primarily water as seen in many of my photographs.
An LE (long exposure) shot can be anything from half a second to hours long. Most LE shots are within the 30 second mark. The reason we vary the length of the exposure is to get a specific desired effect :-)
So here we go.
How do we reduce the light to the camera's image processor?
The first method is a neutral density filter this reduces the light allowed into the lens. This ND (neutral density) filter acts like sunglasses for your camera :-)
You can purchase these in various strength's depending again on the effect you want and the light level you are shooting in.
The second way is to use the aperture of the lens using a high aperture or F-stop eg. F16. Now I know this sounds complicated again but think of it like this... The aperture on your camera acts exactly the same as your own Iris in your eye. When its bright your eye closes so you don't absorb too much light and when its dark it opens wide to absorb as much as possible. We can control the Aperture on the lens in either manual mode (I always use manual), A or AP which is generally the aperture Priority mode. The more we increase the F number or F-Stop the more we close the "iris" hence less light. By decreasing the light in the camera it means we need to take a slower photograph to let more light in which in turn creates the desired motion blur.
Lastly your camera can also by itself vary the exposure time required through the ISO setting. ISO just varies the sensitivity of the light receiver or CCD chip in your camera. The ISO setting should be set to manual and at ISO100 or the lowest real ISO setting on your specific camera.
Combining a neutral density filter, high F-stop (F16) and a low ISO means your camera in the aperture priority mode will need to take a long exposure to correctly expose the image.
Try this 
It pays to experiment, so at sunset tonight why not try taking a photograph of the clouds directly overhead. Firstly setup your Tripod and adjust your Camera's Iso to ISO100 or 200 whichever is your lowest. Point your camera upwards, zoom out fully and set the F-stop to say F16. In aperture priority mode your camera will always select the correct shutter speed. Take a few shots under different light and see the effect. 
Tip: Having a building in the image will help ground the image. This will not create a beautiful photograph but it will help you to understand how it all works.
This is the first of my brief explanations on how to create a long exposure image. My latest image on my Facebook page (kieran hayes photography) and instagram  (@kieranhayesphotography) was taken at sunrise and it was a 20 second exposure with me as a ghost stand in. Ghost images are simply done by standing in the frame of the image while the photograph is being taken for a certain period of time but not all the exposure time. Its vital you stay completely still.
Nb. Always use a tripod. Its impossible to keep the camera steady handheld.