PHOTOGRAPHY BASICS (TIPS)

The Photography Resource
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Basic Photography Tips
Basics of Exposure Exposure and Metering Modes Avoiding Camera Shake Controlling Depth of Field (DOF)
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Basics of Exposure
Exposure is the quantity of light it takes to record a scene correctly. Let too much light into the camera and your pictures will appear washed out and lacking detail in bright areas. Whereas if you let too little light get into the camera, pictures will appear dark and cloudy.
Digital cameras have extremely sophisticated light-metering and exposure control systems, and in most ordinary situations the camera will provide a good exposure with minimal help from you, if you put the camera in 'Automatic' mode, you won't have to intefere with the exposure settings. Having said that, having an idea of how the camera works will help you get a higher percentage of good exposures and give you a good insight into the technical side of photography which in turn will assist you in creating great photos.

To decide how much light is required for creating correct exposure, your camera has a light meter that measures the amount of light reflecting from your subject. Taking into account the ISO speed that you've set (or that the camera has set in the automatic mode), the camera then sets the exposure controls for a perfect exposure. The two basic controls that all cameras use to set exposure are the shutter speed (it determines how long the camera's sensor is exposed to light) and the lens aperture (the size of the lens opening that lets light into the camera). Shutter speeds are described as fractions of a second (or whole seconds for long exposures) and typically range from one or more full seconds up to 1/4000 second. The faster the shutter speed the less time light has to enter the camera; the longer the shutter is open, the more light reaches the sensor.
Lens apertures are described as numbered f/stops; the f/stops designated with smaller numbers (f/2.8, for example) let in the most light, and higher-numbered stops (f/22) let in the least amount of light. In combination, shutter speed and aperture are the gatekeepers that regulate the amount of light that gets to the sensor.
Understanding the significance of the numerical sequences of each control isn't important. It is important, however, to know that the two controls have an entirely reciprocal relationship. If you open the lens by one aperture stop to let in more light (going from f/11 to f/8, for example) and then speed up the shutter speed by one stop (from 1/125 to 1/250, for example), you will get exactly the same exposure. The only difference is that the faster shutter speed stops action better, and changes in aperture affect depth of field.
Exposure and Metering Modes
Getting correct exposure with most simple 'point-&-shoot' (auto-exposure) digital cameras is easy - you simply press the shutter button and the camera does the work for you. However, the more technologically advanced cameras often provide a choice of several exposure and metering modes. Navigating your way through these optional modes may seem somewhat daunting at first, but in reality they actually enable you to completely control your photographs rather than just accepting the images you end up with.
Exposure modes. A choice of different exposure modes enables you to manipulate the camera's shutter speeds and apertures to match your chosen subject so you can tell your camera to pick a fast shutter speed to photograph a moving object such as a car and not end up with a blurred image. Generally, the more expensive the camera, the more options you'll have to choose from, here are some of the most common options:
In Program Mode, you adopt the role of technological slave and the camera automatically selects the shutter speed and the aperture for you. It is often called the green mode because it's frequently marked by a green "P" on the mode-selector. The camera will choose a shutter speed that is safe enough for hand holding and an aperture that will provide a moderate amount of depth of field. It's ideal for shooting fairly still subjects like a tree blowing gently in the wind that doesn't require either a very fast, or a very slow shutter speed and likewise it does not require an extensive or shallow depth of field - the settings in automatic mode will be very 'middle-of-the-road'.
In shutter-priority mode you select the shutter speed and the camera chooses the appropriate corresponding aperture. For example, if you want to blur the water rushing over a waterfall, you can select a slow shutter speed and the camera will choose the aperture. Conversely, if you want to capture a race horse mid gallop, you can pick a fast shutter speed and, again, the camera will select an appropriate aperture so you get a sharp image.
Aperture priority mode, lets you pick the aperture, while the camera selects the matching shutter speed. This option should be chosen when you want to manipulate depth of field. For example, you could set a small aperture for extensive depth of field, when shooting a vast landscape, or a large aperture when you want to limit depth of field when shooting a portrait or close-up.
Metering modes allow you to control which part of a scene the meter will take its reading from—This is an extremely useful function when you require good exposure when you have difficult natural lighting.
Matrix metering is used in virtually all digital cameras for the simple reason that it is the most reliable and sophisticated type of automatic light metering. Matrix metering works by dividing the viewfinder into a series of zones and taking separate readings from each of them. This information is then fed into a chip that has been programmed with literally hundreds of thousands of potential combinations, the meter then selects what the important parts of the scene are and chooses the best matched exposure.
Center-weighted metering is a type of 'averaging' meter where the entire viewfinder image is metered but the reading area is 'weighted' to give more emphasis to an area at the center of the frame. Typically the meter will give 75% emphasis to the material at the center of the frame and 25% to the remaining area of the frame. The logic of this method of metering is that since most photographers place their subjects in the center of the frame, that's where the most important metering should be done. Is this method accurate? Yes, if you place your subjects in the center of your photograph. However, you can place your main subject in the center of the viewfinder for metering purposes (usually half depressing the shutter button) and then you can move the subject to anywhere in the viewfinder (whilst still half depressing the shutter button) without altering the metering settings.
Spot metering is a further refinement of center-weighted metering, but spot meters read only a tiny portion at the center of the frame—usually from 3-5% of the frame. This metering method is very accurate if you are careful to read only the subject area of the frame. Imagine a scene where the important subject area (a deer running across a snow covered country estate for example) is surrounded by a large field of bright or dark subject matter (the snow). By using spot metering, you can meter just the subject and exclude the large area of snow that would normally fool your light meter. Avoiding Camera Shake
The quality of camera lenses nowadays is that good that expensive digital cameras can take acceptably sharp pictures. So why is it then that 'blurry' pictures is still the main issue among most photographers?
The answer is simple, however expensive the camera, peoples hands still shake... To get really good sharp images, you have to hold the camera steady or rest your camera on something (ie a nearby fnce or gate) or a camera tripod. Additionally, you have to depress the shutter button very gently. Whether you're using a point-and-shoot camera or a Digital SLR, the best technique is to rest the camera in the palm of one hand and squeeze the shutter button gently with your free index finger.
More recently a technology called 'anti-shake' or alternatively known as 'image stabilization' or 'vibration reduction' has begun to appear on cameras, and it has become very successful in providing sharper images even at slower shutter speeds. In fact, most anti-shake systems enable you to shoot at shutter speeds up to two or three stops slower than possible using a camera without anti-shake. Look for the initials 'AS', 'IS' or 'VR' in the camera you are buying or with DSLR camera's check either the camera body or the lens to make sure it incorporates this technology. Ultimately you will pay more for a camera or lens with anti-shake but it's a worthy cost to pay.
Whatever the camera or technology, some basic facts apply: The effects of camera shake increase the more you zoom in on a subject as these lenses magnify vibrations. Also as telephoto and zoom lenses are larger and heavier, this inevitably increases the chances of your hand shaking whilst trying to hold the camera still. Camera shake is far more likely to ruin your photo at shutter speeds of 1/60 second or longer, and most digital cameras have a 'camera shake' warning that will warn you to either use a higher shutter speed (which might require setting a higher ISO speed) or use a camera support, such as a tripod or monopod. If you have the space available to carry a tripod and the time to set one up then this is highly recommended - be aware though that if your camera does have an anti-shake function, this may need to be turned off when using a tripod as it can have the opposite effect.
Controlling Depth of Field (DOF)
The subject of depth of field can be intimidating for many amateur photographers, but the concept is actually quite simple. It is the range in a scene, from near to far, that is in sharp focus. The ability to control which parts of a scene are in focus has an immense effect on your images. For example, when shooting a landscape you'll want as much of the photograph in focus as possible, so a great depth of field will be required. However in other situations, such as close-up's, abstract images and taking portraits, a shallower area of sharp focus will seperate your subject from distracting backgrounds giving a much better contrast to your end photo.
Three aspects control how great the depth of field will be in a photograph: lens focal length, aperture, and the distance you are from your subject. Other things being equal, shorter-focal-length lenses, smaller apertures, and larger distances to the subject all increase the range of sharp focus, while longer lenses, wider apertures, and a shorter distance to your subject shrink the depth of field you will experience.
however when you look through your lens, you will not see what's really sharp and what's not, this is all done in the image processing of the camera. With point-and-shoot cameras, this is because you're not looking through the lens, you're looking through a secondary viewfinder. With Digital SLRs, you're looking through the lens at its widest aperture; it closes to a smaller f/stop only at the instant you press the shutter button. This is a problem if you're using a medium telephoto lens to take a photo of a person in amongst a busy street. As you look through the lens, it appears that the traffic and crowds in the background are out of focus. But because you have a small aperture set, however when you look back at the photo, your subject is lost in amongst the business of the rest of the photo.
The solution? Many Digital SLRs have a depth-of-field preview button; when you press it, the lens briefly closes to the shooting aperture, showing you the real depth of field. Be aware that when you press this button, the image in the viewfinder will temporarily darken. If too much is in focus, simply open the aperture, put on a longer lens, or move closer. Or do all three. If too little is in sharp focus? do the reverse..
The main thing to remember is to go and practice on the basics so that when you get the chance to capture that 'killer image', you get it right - rather than practicing on the 'killer image' and not capturing it well.
Good luck and above all, have fun !