EXPOSURE TIPS. Camera shake causing blurry pictures

Transcription

1 EXPOSURE TIPS Camera shake causing blurry pictures Hold your camera steady Digital cameras are usually held away from the body to view the LCD screen to compose the picture. This is less steady than the old camera position which were held up close to the eye and allowed the elbows to be braced against the body. Press the shutter button gently Some people stab the button down causing the camera to move. Also as the button is usually on the right hand side of the camera the action of pushing it sometimes twists the axis so that your images appear to be on a slant When you push the shutter button the picture is NOT taken instantly. There is a slight delay after you have pushed the button while the camera lens does an auto focus, ( the less light contrast there is the longer this takes ). Then it calculates and sets the correct aperture and exposure. Then it applys power to the CCD chip to sensitize it. Then it takes the picture. This slight delay sometimes means the person may have been holding the camera steady but then starts to move before the sequence of taking the picture has been completed. Also this slight delay often catches us out when taking action pictures. Imagine taking a picture of somebody jumping into a swimming pool. To catch them in mid air requires anticipating the moment when pressing the button otherwise you just get a picture of there splash. All digital cameras have a slight delay and its extent varys between models and brands. Leica and some Panasonics at the present time have the fastest responses. SOLUTION FOR CAMERA SHAKE Press the shutter button gently. Remain holding steady untill full exposure sequence is completed. Where possible steady yourself by leaning against a wall or lamp post, or resting the camera or elbows on a table. When composing the picture most cameras have the function of gently half pushing the shutter button to preset the auto focus and exposure calculation which may reduce the delay time slightly. Also read the section on the action symbol for another tip on reducing camera shake Tripods A tripod will solve many camera shake problems and you do not have to use huge unwieldy profesional ones. There are many small lightweight table top models available for about $30 which will fi t into a handbag. Most of your pictures will be taken on the full auto settings, usually set by the camera symbol, or a green rectangle or the words Auto. There are usually also variations on most cameras to supplement the auto function. Before discussing these we have a short explanation of correct exposure and depth of fi eld which will then make our explanation and understanding of the symbols easier.

2 A Photograph is formed with 3 elements, Aperture Size, Exposure Time and Sensitivity. Sensitivity is how responsive the CCD chip is to light On old fi lm cameras you purchased fi lm of different sensitivity and it was expressed as an ISO number, and 400 are the most common. The higher the number the faster or more sensitive the fi lm. Digital cameras use the same ISO numbers to express the fastness of sensitivity. The sensitivity of the CCD chip is altered by applying more or less power to it. Aperture is in the lens and can open and close to let more or less light through Usually expressed as a stop or F number. The larger the opening the more light will pass through and the smaller the opening the less light will pass through. Exposure time is the length of time that the shutter is open Usually expressed in fractions of a second, but in low light situations can be on digital cameras up to 30 whole seconds. The auto function on your camera measures how bright the light levels are and calculates how much light is needed and sets automatically the aperture, exposure time and sometimes the CCD sensitivity. Depth of Field When you take a picture on a sunny day your subject will be in sharp focus and so will the background for a distance of about 10 metres, the foreground will also be in focus for a similar distance. This is the depth of fi eld. In this example about 20 metres The Aperture size controls the depth of fi eld The smaller the aperture size the longer the depth of fi eld will be and the larger the aperture size the shorter the depth of fi eld will be If we doubled the size of our aperture in our example we could shorten the depth of fi eld from about 20 metres down to about 15 metres; and with even larger apertures shorten it even further. Of course if we doubled our aperture size we will let twice as much light through and our exposure would be wrong. So to correct it we would have to halve our exposure time. Understanding this will allow you to then chose some of the other Auto scene symbols for even better pictures.

3 AUTO SETTINGS and variations Most of your pictures will be taken on the full auto settings, usually set by the camera symbol, or a green rectangle or the words Auto. There are usually also variations on most cameras to supplement the auto function These are often called scene menus and often have symbols on the Auto switch and/or on the LCD display screen. Such as displayed on the pictures below from a Canon and Sony cameras The Symbols on most recognised brands of cameras are similar to these. First of all we will discuss the Flash off or fl ash stop function. When set to standard auto the camera will determine the exposure and if light levels are low will automatically pop up and activate the fl ash. If the Flash Off symbol is selected the fl ash will not pop up or go off. When would you use this setting? If you were photographing young babies, wild life and animals, things you did not want to startle or frighten If the fl ash was giving refl ections from glass or shiny objects. such as peoples glasses or trying to take pictures through shop or car windows. Night scenes of distant fl oodlit buildings Some Nikon cameras have a different symbol and call it the Museum setting, as many overseas museums allow only non fl ash photography inside. This is the fl ash on or forced fl ash symbol as used on Sony cameras The fl ash will go off for all pictures. Not all cameras have the forced fl ash command It is usefull for providing shadow illumination such as when taking pictures on very bright days with dark shadows

4 Two versions of the Landcape Scene Symbol When this symbol is set the auto function is meant to favour a smaller aperture to assist the focus going out to infi nity. My experience with several different brands and models has been that there is no discernable difference between this and standard Auto setting and I no longer bother with using this settings. The fl ash should be suppressed with this symbol and it can be used for night shots sometimes instead of the night symbol. Try some tests yourself though. Portrait Symbol Professional Photographers take portrait pictures with very short depth of fi eld to focus all interest in the picture on the subject and usually use plain backdrops which are also out of focus. When you set this symbol the auto function favours a larger aperture and shorter exposure to shorten the depth of fi eld. If your subject is outside in good light conditions you will not see any noticable difference, but inside in lower light levels it works quite well. To enhance the affect make sure your fl ash is suppressed, use a plain background and have your subject stand at least a metre in front of it. Action Symbol In my view the most useful symbol to use with great affect and not just for action. When you set this symbol the auto function favours a shorter exposure to catch action movements; but in addition to this most digital cameras then also automatically increase the CCD sensitivity to allow it to operate with even shorter exposure times again. My Canon camera increases the ISO number to 400 but you should check your own manual to see if yours does the same. You can use this setting for action or moving subject shots of course; but it is also usefull to set for inside shots where the light levels are lower to reduce exposure times. Very handy to use for night shots such as fl ood lit buildings. Try all sorts of tests yourself, its a great setting symbol. Most cameras also have a function to take 3 or more pictures quickly in sequence which may assist you in capturing action shots such as the example of somebody jumping into a swimming pool. Read your manual to see how to set this for your particular camera. Also if you are having trouble with camera shake you should use this setting symbol to help reduce the movement and increase the sharpness of your pictures. With fi lm when you increase the sensitivity by using higher ISO numbers you also increase the grain affect in the fi lm. With digital cameras when the sensitivity is increased you get a similar affect to grain in your picture which is caused by electronic noise. Most of the time this will not be noticeable, but may be more noticable in bigger enlargements printed out and particularly in night shots and time exposures.

5 Close Up Symbol also sometimes refered erroneously as a macro setting When this symbol is set the auto function is meant to favour a smaller aperture to assist the auto focus which is also allowed to function at much closer ranges. Close ups always have short depth of fi elds and focus is critical. So on most digital cameras this symbol only functions when there is little or no zoom used. This usually defeats the object of trying to get a close up picture of say a fl ower or insect as full zoom from farther back will most likely give you a better result. Technically it does work, but for practical use there is no discernable benifi t. Close up and Macro photography as you see in magazines is a specialised subject using expensive lenses and ring lighting and you will not be able to match it with any standard digital camera. for further information see the web site Beautiful Bugs: How to Do Macro Insect Photography at Night Symbol When you set this symbol the auto function allows the camera to take up to the maximum time exposure for your camera, possibly up to 30 seconds without the fl ash fi ring. For fl oodlit buildings such as the skytower exposure may be in the vicinity of 6 to 10 seconds. So you will need to use a tripod or stand the camera on a wall or something to avoid getting a blurry picture. Night Portrait Symbol Not all cameras have this symbol function. It allows the fl ash to fi re at a low level while synchronising with a long time exposure. Its use can be in taking say a portrait type picture with a sunset background. The low level fl ash captures the detail of the person in the foreground while the extended exposure captures the sunset background. The subject must remain still after the fl ash has gone of to prevent getting blurry features though. Great for getting all sorts of artistic effects. Try it out on some evening street parades. With all the different symbols there are no must not rules, you are only limited by your own imagination. Try anything out, the beauty of digital camera is there is no cost to trying out different effects as if it doesnt work you can easily delete.