Camera ISO, Aperture, & Lens

ISO

• Generally defined, ISO is the camera's sensitivity to light. • If the camera has a low ISO, the camera will be less sensitive to the light

coming in. • If the camera has a high ISO, it will be extremely sensitive to light. ISO

settings are as follows: 100, 200, 400, 800, and 1600. • If you have a high-end DSLR camera, you might have ISO settings as high

as 6400. • As much as possible, you want to be able to get the lowest ISO setting on

your camera, which in most cases is 100. This way, your pictures will always be of the highest quality.

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ISO continued

• However, in low light situations, this is not always possible. If you've already tried your best to adjust your shutter speed and aperture to let in most light possible, another solution to getting better light is to make your ISO higher. Although the picture will be grainier, the exposure will be better.

• If you are in a bright location, where there is plenty of light (outside), you should always check and make sure that your ISO is at 100. Bumping up your ISO to 200 or 400 won't affect the quality of your pictures that much, but if you make your ISO 1600, you'll definitely notice a depreciation in quality.

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Noise (digital) is Grain (film)

• Noise in digital photos consists of any undesirable flecks of random color in a portion of an image that should consist of smooth color. It is somewhat similar to the "snowy" appearance of a bad TV signal. Digital images shot in low light or with a high ISO setting often exhibit this undesirable noise.

• In a way, noise is the digital equivalent of film grain, but noise is generally undesirable, while grain can be desirable. In fact, some digital photographers will curse noise one minute, and the next they may try to create film grain in digital photos for an artistic effect.

• Much of today's photo editing software offers tools for reducing noise in digital photos, as well as filters for adding noise for a film grain effect.

Digital Noise

Aperture

The aperture is the size of the lens opening. It controls the amount of light let in: a larger aperture lets in more light, while a smaller aperture lets in less light.

• An aperture is made out of aperture blades (usually five to nine) that form a rough circle to control the size of the opening, and therefore the amount of light let in. The size of the opening is that f/number. Basically, that f/number is a ratio of focal length to aperture diameter. Do you need to know this? Not really, except you should keep in mind that the aperture is a ratio.

The lower the f-stop number means more light is let into the camera. The higher F-stop number means less light is let into the camera

• Now, lets get on to why this matters and how it can change what your picture looks like. Basically, a larger aperture (lower f/number) will have your subject in focus, and everything in front of and behind it blurry. A smaller aperture will have your subject in focus and everything in front of and behind it quite focused as well. Take a look at the following diagram; the further apart the lines are, the more out of focus something is:

We will call this “opening up” the aperture

• Selective focus examples – best selective focus happens f-4 or below.

Small aperture or “stopped down” produces “hyperfocal distance” or excellent depth of field.

The hyperfocal distance is the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp. When the lens is focused at this distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp.

• Aperture stopped down = Hyperfocal distance – best f-stops f 11 and above

• In optics, particularly as it relates to film and photography, depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image.

• It may be desirable to have the entire image sharp and a large DOF is appropriate. In other cases, a small DOF may be more effective, emphasizing the subject while de-emphasizing the foreground and background.

• The DOF is determined by the camera-to_subject distance, the lens focal length, and the lens f-stop number.

Depth of Field

Choosing a Camera lensfrom www.photography.com

• Choosing camera lenses demands both knowledge of and experience with different types of camera lenses. Although knowing which lenses work best in given conditions is important, a photographer also chooses a particular lens to produce a specific photographic effect. Light, composition and subject matter of a scene all influence photographers’ choices of lenses. A fast lens means? A slow lens means?

Wide Angle Lenses

• Although some will take landscape shots with telephoto lenses, most photographers opt for the wide-angle lens. Because a wide-angle lens has a wider field of vision than the human eye, it can take in more of a topographical expanse. Consequently, the wide-angle lens is one of the preferred landscape camera lenses. A wide-angle lens can focus on the foreground and background simultaneously, another ability that the human eye lacks. Wide-angle camera lenses are best for large, dynamic landscapes where background and foreground both catch the eye’s attention. However, a photographer should refrain from using a wide-angle lens if he wants to focus in on the details of a single, distinct subject.

Zoom Lenses

• A zoom lens allows the photographer to widen or shorten the lens’ focal length to increase or decrease the magnification of the subject. This feature makes the zoom lens a popular camera accessory in many types of photography, ranging from landscape to portrait photography. However, because zoom lenses have small apertures (or lens openings), they are not well suited to taking pictures in low-light conditions. Zoom lenses have replaced the fixed focal length camera lens in most camera models, especially with the advent of digital cameras. When choosing camera lenses, bear in mind that an optical zoom lens and a digital zoom lens are different. While an optical zoom lens magnifies the image, a digital zoom lens crops the image after the maximum zoom is reached. Essentially a digital zoom enlarges and crops the image seen in the viewfinder instead of magnifying the subject. This digital enlargement results in lower resolution and, therefore, a poorer quality image. When choosing camera lenses with zoom capabilities, photographers should look for high optical zoom capabilities rather than being deceived by claims about digital zoom capability. Pictures are of much better quality with an optical zoom lens.

Telephoto Lens• The difference between a zoom lens and a telephoto lens is subtle. A zoom lens

enlarges and magnifies the image. In contrast, a telephoto lens brings the subject “closer” to the photographer, reducing the distance between objects in the photograph and the camera’s lens. This allows a telephoto lens to show greater detail than the human eye could see at the same distance.

Fixed-Focal Length Camera Lens

• A fixed-focal length camera lens is a permanent, non-adjustable lens found on some low to mid-range quality cameras. Often (but not always) doubling as a wide-angle lens, fixed-focal lenses tend to work well for low-light photos. A fixed-focal length lens can do wonders for beginning photographers by helping them learn the art of photography. Without zoom capabilities, the photographer must give more thought to basic photography composition to produce good quality shots. Consequently, a budding photographer may learn the basics of good photography faster if by choosing a fixed-focal length lens. They are less common today but still available from photography supply stores.

Macro Lenses A macro lens is used to take extreme close ups of objects. Its short focal

length allows the photographer to take pictures at close distances without distortions. The resulting image is as large as, or larger, than the original subject. Choosing a macro lens has been complicated by digital camera settings. Originally, a macro lens was an extension tube for the camera lens. However, today’s digital cameras often have a macro setting. Although the setting replaces the traditional lens, it still produces the same effect as the previous macro lenses. Macro lenses or macro settings are best used for magnifying the details of already small objects. For example, a photographer can use his macro setting to photograph ripples in water, the dew on a flower petal or the crevices of a rock.

Fisheye Lens• Fisheye camera lenses distort the subject image, producing photos with

curved and convex appearances. The fisheye lens was developed for astronomy photography that seeks to capture as wide a range of sky as possible. Today, the fisheye lens has become popular with landscape photographers, as the lens distortion curves horizons and hints at the earth’s curve. A portrait of a person taken with a fisheye lens has the distortion similar to what’s seen when looking through a door’s peep hole.

• Telephoto lens

• Wide angle lens

• Fisheye lens

• Macro lens