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Digital zoom is when an imaged is cropped and is magnified as a result of the cropping. Digital zoom is a way of reducing the angle of the digital photograph or video image. Digital zoom is done when an image is cropped down to the same aspect ratio to a cantered area to make it look like the same as the original image. Doing this usually also changes the dimensions of the original images pixels. This is always done electronically without having to adjust the camera's optics. No gain in the optical resolution occurs during this process.
Digital zoom in a camera lets you get closer to a subject or an image when you want to take a picture from a distance so's not to get in the way of the picture with shadows or in the way of other people or subjects. Although this may make the image quality not as good as it could be.
Some digital cameras rely entirely on digital zoom, lacking a real zoom lens, as on most cameras. Other cameras do have a real zoom lens, but apply digital zoom automatically once its longest focal length has been reached. Professional cameras generally do not feature digital zoom.
In general cameras will allow you to zoom continuously from optical to digital or stop the optical zoom and then press the zoom switch a second time to engage digital zoom.
Optical zoom lenses physically extend to magnify your subject. A motor controls the lens movement. When you press the switch to "W" or "T," the subject is either magnified or reduced in size. The W stands for a wide angle where as the T stands for telephoto.
Optical zoom work using lenses and moveable components. This is the same way a zoom works on a traditional camera. By changing the distance between lenses, the focal length can be altered, reducing the field of view but increasing the magnification. Optical zoom do not change the number of pixels used to create an image, so result in clear zoomed photos. Optical zoom tends to be better than digital zoom.
Digital V's Optical:
It is useful to have both forms of zoom, but optical gives you much sharper images and better resolution than digital zoom. However, a digital zoom is very easy to use, for short distances or for beginners; it can be a very handy function. Another benefit is that you probably won't have to crop or alter the picture when it's in your PC.
The important thing is not to be convinced into buying a digital camera based on the power of its digital zoom. It's more significant to consider the power of the optical zoom - as well as a range of other features.
Resolution of the images.
This shows the details that an image may hold. It is used in all types of imagery from film imagery to optical and digital imagery. The resolution of an image can be measured in a number of ways. The resolution shows how close the lines are to each other and how visible they are without becoming blurred. 'Resolution units can be measures in physical sizes such as lines per inch or lines per mm Photographic lens and film resolution are most often quoted in line pairs per millimetre'
File size, file types-
File types and its quality:
Tiff, LZW lossless compression
JPG, High quality
JPG, medium quality
JPG, my usual web quality
JPG, low quality / high compression
JPG, absurdly high compression
PNG, lossless compression
GIF, lossless compression, but only 256 colours
Controlling The exposure in a camera.
Exposure is the light entering the camera through the lens.
There are two things are used in a camera to limit the amount of light coming into the camera; these include a shutter along with an Aperture.
· In a camera there is a shutter. The shutter in the camera blocks the light from hitting or exposing the film until the photography presses the button to take a picture. Once the button is presses the shutter opens quickly and then it closes which allowed enough light to hit the film and take a image of what is being seen through the lens. The shutter speed can be altered using the shutter speed settings in a camera which will change the time the shutter stays open.
· In a camera there is an Aperture. The aperture allows light to pass through a camera's lens an opening called an 'aperture' must be kept clear to let the light pass through the camera and hit the lenses. An aperture is a small hole and when it is open lots more light is let in, when it is open only slightly less light is allowed through.
How long the shutter remains open depends on the shutter speed.
Examples of this include when "A 1/2 second exposure is darker than a 1 second exposure" Another example is a '1/125 exposure this is TWO STOPS brighter than let's say a 1/500 exposure would be.
The longer the exposures the increase in light a film gets than if it was subject to ashorter exposure. The bigger the fraction the less light that is let through. So with a one second exposure more light that is allowed through.
The light that is passed through the camera lens can be controlled using an F-Stop which is usually built in into most cameras.
We can think of the aperture as the pupil in a human eyeball. Like the pupil the aperture in a camera can control the amount of light hitting what's behind the lens. To be able to do this it closes up and restricting the light by opening up or closing to let more or less light in. Lower F-Stop numbers indicate more light.
Controlling shutter speed and aperture size:
Automatic Image Focus is when the camera automatically focuses on the whole image, not only the subject will be brought into focus but the background surrounding it as well. If manual focus is used then this will only bring the detail and focus of the subject alone whilst the background will remain blurred to make the subject sound out more.
Fixed lenses are lenses that cannot be moved; they are attached to the camera and can only be used to zoom in and out. Many fixed lenses do not have the ability to be Able to change the focus of the image it is looking at. Most fixed lenses are attached to cheaper digital and optical cameras as the majority of people that use them are normal everyday people.
Zoom lenses are lenses that have the ability to zoom in closer to an object without the overall detail of it being disturbed. These lenses are used for larger pictures where the detail is needed such as at weddings or when taking photos of the country. Lenses can come in various sizes and the better the lens the better the final picture
Macro settings can be used when you are taking an image of a very small subject such as small insects. This allows you to focus on the subject when the lens is very close in. this means that you will have a high quality image of the subject. There is usually very little of no blurring when using macros.