Modern cameras are amazing – anyone can take a nice picture with the camera set to automatic. But taking pictures that really shine might require a little more know-how. Flipping the camera dial off “automatic” can be a little intimidating, but the results will be well worth the effort. Before flipping the dial it’s important to understand some camera basics.
Photography Basics – Shutter Speed
When the shutter release button is pushed to take a picture, the shutter is opened to expose the camera’s sensor to the image in view and then closed after a certain amount of time. How long the image is exposed to the sensor is determined by the shutter speed. Faster or slower shutter speeds will have different effects on a picture. A fast shutter speed is useful for freezing action, like in sports photography. A slow shutter speed is useful for low light photography or for artistic effects like a motion blur.
Fast shutter speeds are measured in fractions of a second like 1/200 of a second and can stop action like the falling pear on the left, above. Slow shutter speeds can be small fractions like 1/15 of a second (pear on the top right) or even full seconds like 30 seconds.
Hand-holding a camera can be difficult at slow shutter speeds because the photographer’s hand might shake. The general rule of thumb is that hand-held shutter speeds should be at least “1/focal length”. This means that with an 18mm lens, the photographer should use at least 1/18 of a second or with a 200mm lens use at least 1/200 of a second. This is just a guide, however – some photographers have steadier hands than others.
Photography Basics – Aperture
Camera aperture is similar to the pupil in an eye. The aperture diameter can be made larger or smaller depending on the photographer’s desired effect. The larger the aperture diameter, the smaller the f-number and vice versa. These numbers can be confusing, but just remember larger diameter = smaller number. For example a large aperture is f/2.8, whereas f/11 is a small aperture.
Larger apertures allow more light to hit the image sensor, therefore shutter speeds can be faster. However, larger apertures result in a photograph with less depth of field, meaning things farther away than the main focus point will be out of focus. In the photos below, notice how as the aperture diameter decreases (larger number) the background objects begin to get more in focus.
Being able to choose which part and how much of a photograph is in focus is very important to photography. The photographer can tell his or her audience what’s important or where to look, simply by setting the focus point and depth of field.
Summing up Shutter Speed and Aperture:
-Faster shutter speeds are great for catching action.
-Slower shutter speeds can be used for blur effects.
-Faster shutter speeds are easier to hand-hold.
-Larger apertures allow more light which allows a faster shutter speed.
-Smaller apertures allow less light, but they put more of the image in focus (see depth of field).
Photography Basics – ISO
Put simply, ISO allows photographers to “cheat” and double the amount of available light. With cheating comes consequences. As ISO is doubled, image noise or graininess increases. 100 ISO is usually the starting point for most cameras, although some go lower. A photograph taken at 200 ISO will have twice as much light as 100 ISO. (400 is double 200, 800 is double 400, etc.) This is helpful for taking photographs that need a higher shutter speed, such as action, or hand-held low-light pictures.
With today’s modern cameras, photographers can cheat light over and over again. Entry level DSLRs usually offer a maximum ISO of 1600 or 3200, but more expensive cameras can do 6400, 12800 even up to 102400 ISO.
With an entry level DSLR, noise will start to become apparent around 800 ISO, but the higher end cameras can take pretty good shots with acceptable noise levels in the 1600 and 3200 range.
Below are pictures of the pear at 100% crop (actual image size) taken with a Canon Rebel XSi (450D)
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