Auto no more…

Understanding Exposure part 3

Yesterday in part 2 I used buckets, water and hoses to explain exposure to you, hopefully you had a chance to read it, if not, I suggest you do so you’re up to speed before jumping into part 3! You will find part 2 HERE

Now that you understand a little more about exposure, it’s time to look at why you would want to be able to make changes to shutter speed, aperture or ISO.

Today we will be looking at what adjusting the shutter speed does…

Basically, you leave the shutter open long enough to allow enough light in for a correct exposure, just like in the example of the bucket, you left the lid off until it was full of water. What you need to know is  a faster shutter speed will ‘freeze’ motion whilst a slower shutter speed will ‘blur’ motion. Using a slower shutter speed is how to get silky smooth waterfalls, show motion blur in propellers and wheels and more… sometimes creatively it is important to be able to depict movement, and slowing your shutter speed will help you achieve it. However, if you’re taking a photo of something that isn’t moving, the last thing you want is for it to be blurry, if you want an image that is not blurry it is known as being ‘sharp’, to achieve a sharp image you have two choices, one option is to use a tripod to keep your camera from moving as the exposure is taken, the second option is to speed up the shutter speed so it is so quick, that any movement is ‘frozen’. Just remember if your subject is moving, even a tripod won’t help…

Unfortunately, if the available light is low you cannot just use a faster shutter speed, this is why flash is used in some low light situations. If you don’t have a flash, or don’t want to use a flash, it is possible that you will underexpose your image if you don’t let enough light in, and if you leave your shutter open long enough to let the light in, you may end up with an unwanted blurry image! In the next couple of days I am going to show you how to best overcome this issue using aperture and ISO.

the daily pic – Silky Smooth Water

This photo shows you what is possible with a longer shutter speed. I had to use a special filter called a ND (Neutral Density) filter that blocked some of the light from entering my lens, it allowed me to keep the shutter open for 20 seconds. To do this I also had to mount the camera on my tripod and used a remote to activate the shutter otherwise other parts of my image would be blurred. I wanted to make the water blurry, this is how to achieve the silky smooth look…

(Click on the photo to order yourself a print or to download (please see licensing for the rules!)

Categories: Australian Locations, Blue Mountains | 1 Comment

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One thought on “Auto no more…

  1. Pingback: Noisy or Blurry…. « On Three Legs HDR Photography

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