Camera Lenses Explained
Single-lens reflex cameras offer photographers the opportunity to change lenses depending on what types of pictures are going to be taken. Camera lenses vary in zoom type, aperture, focal length, focus type and cost. Knowing what these variables refer to and what you need will help you set a budget and get the most for your money.
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Zoom Type
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Some camera lenses are known as primes, which means they have one fixed focal length, such as 50mm, and cannot zoom. Others are zoom lenses, which means they cover a range, such as 24mm-70mm, and can be adjusted. The advantage to prime lenses is that they usually produce slightly higher quality pictures.
Aperture
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Aperture is the amount of light the lens can allow through it to hit the sensor or film in the camera. The wider the aperture, the more light is let in. This is important because the more light that can enter, the faster the shutter speed can be to freeze high-speed action.
Focal Length
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Focal length is measured in millimeters and tells the viewing area of the camera. The human eye's viewing area is between 40 and 60 millimeters. Lenses with higher focal lengths will zoom in closer than the eye is able to.
Focus Type
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Most camera lenses today come equipped with automatic focus and manual focus. Automatic focus is when the camera sets the focus while the manual setting allows the photographer to set the focus. Some cameras also offer full-time manual focus, which is a special twist to automatic focus. Unless the camera has full-time manual focusing, the photographer cannot adjust the focus when the lens is set to automatic focus without risking damaging the lens.
Cost
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Camera lenses can cost under $100 or more than several thousand dollars, so deciding your budget is important. If you need the perfect picture every time, you may invest in multiple prime lenses. However, if you just want one lens to stay on the camera at all times you might consider a cheaper lens with a wide range of focal lengths so it can be used for any picture, near or far.
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