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Buying a camera - the big issues

Discussion in 'Help Team' started by Lounge Lizard, Jul 23, 2007.

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  1. Lounge Lizard

    Lounge Lizard Well-Known Member

    Image Stabilisation (IS)
    This is a very complex but clever system whereby the camera counteracts movement of the users hand which normally leads to blurry pictures caused by what is commonly known as 'camera shake'. This is seldom seen under normal lighting conditions but when light levels fall (or the camera is being used indoors without flash) and the camera selects a slow shutter speed to permit more light to reach the sensor and thus record an image. Those familiar with photography will also know that longer focal lengths i.e. at telephoto settings, will also exaggerate camera shake and IS is also useful here. Many photographers have grown up without IS and have steadied themselves against trees and other solid objects or use tripods and bean bags to minimise camera shake. These techniques can still be employed so IS is often seen as a useful feature and not necessarily a 'must have' feature though the importance of this is largely a preference of the user. Whatever, IS actually works and can make a big difference to some photos.

    This is seen as a coloured speckling on the image most noticeably in the shadow areas. Some people liken it to film grain and, like film grain, the higher the sensitivity of the sensor (cf. higher film speed), the more likely you are to see it. The noise is actually electronic noise caused by strong amplification of a weak signal recorded by the sensor and since compact and bridge camera have small sensors and hence smaller photo sites on the sensor, they don't collect as much light and therefore give a weaker signal, need more amplification and thus tend to exhibit more noise. Some cameras are worse than others but generally at ISO 100 it is hardly seen, if at all. At ISO 400 on a compact, it may be visible if examined closely (depending on the camera and its built-in noise processing) but may not be visible on an enprint. However, it is likely to show in enlargements as a speckling or as a softening of the image. dSLRs are much better than compacts or bridge cameras in this respect as they have much bigger sensors.

    This is a controversial issue. Dust has always been a problem in photography. If dust gets on film, it may degrade just the one frame where it happens to sit. If dust gets on a sensor, it could degrade all images since the sensor is fixed and the dust doesn't move for the next exposure. Dust shows itself as small dark out-of-focus blobs on the image. Some cameras now have anti-dust systems built-in which can clean the sensor on start-up or shut-down. Is it really a problem? No. Most experienced photographers will use a blower brush to blow dust off the sensor. Some people say that this is a dSLR issue because users change their lenses thus exposing the internals of the camera to the environment. Compacts and bridge may be better protected but there are reports of users with these having dust problems too. The only problem here is that they cannot remove the lens to get to the sensor to clean it. In reality, dust is not something that should keep you awake at night. It can be dealt with whether you have a camera with an anti-dust measure or not.

    This is sensitivity to light and corresponds to the ratings used on films (also known as 'film speed' or just 'speed'). Most cameras operate at about ISO 100 which is fine for general photography in good daylight. Under gloomy conditions or at the ends of the day, you may need to use ISO 200 or ISO 400 to get acceptable exposures before resorting to artificial lighting or flash. ISO 400 tends to be the maximum practical speed for a compact or bridge camera (noise starts to become intrusive) but a good dSLR can go up to ISO 1600 or even ISO 3200 and still get good results. The general rule is the the lower the ISO, the better the quality of the image.

    Focal length range (zoom range)
    Nearly all cameras have some kind of zoom lens fitted to them or sold with them in the case of dSLRs. A zoom lens gives your camera the ability to see more of the scene around you (wide-angle) or enables you to home in (zoom in) on a small portion of the scene or perhaps a distant object. The degree to which the lens can do this is known as the zoom range. Most cameras have lenses that permit moderate wide-angle to moderate tele focal lengths ('tele' means telephoto or a magnification greater than 1). A moderate zoom lens may cover a range of focal length whereby the longest focal length is numerically 3x the shortest focal length - this is known as a 3x zoom. A more advanced compact may go up to 6x while a bridge camera may go up to 10x or more. dSLRs either come without a lens (sold as 'body only') or come with a short zoom range starter lens (2x - 2.5x).

    Optical Zoom vs Digital Zoom
    Digital zoom is simply blowing up the image captured by the sensor. The subject may look bigger or closer but is no more detailed than the original image. Optical zoom, on the hand, uses the lens by permitting you to zoom in and capture more detail. Unfortunately, an optical zoom may result in a bigger or bulkier camera than one without. If you only need images for the web or enprints then a digital zoom may be fine. If you use a computer, you may prefer to not use digital zoom and just crop the image how you wish on your computer.

    A lot of people like the idea of photographing insects and flowers and want a 'macro' facility. Macro really means 1:1 or greater i.e. the size of the subject on the sensor is the same as the size of the subject in real life or is even bigger than real life. Unfortunately, the word 'macro' is misused in the camera industry and many manufacturers use it to really say that their camera or lens can focus closely, sometimes as close as a few cm from the lens. It does not mean that resulting image is really 1:1. Many compacts and bridge cameras have a close-focus mode. With dSLRs, it depends on the lens. Real macro photography usually means a special high quality fixed focal length lens. However, the close-focus abilities of the compact or bridge camera is often more than adequate for most people who don't specialise too much in this type of photography.

    Crop Factor
    This only really applies to dSLRs and will only have meaning to you if you are coming from a 35mm film background. To put it simply, the sensor in many dSLRs is smaller than 35mm film so it 'sees' a small crop of the central portion of the scene when comparing the same lens and focal length between a 35mm SLR and a dSLR. In many ways, it is like a zoom factor or magnification factor and this is how many people rate it. So, if somebody says a camera has a crop factor of 1.5, it means that the sensor is smaller than a 35mm frame and the effect is rather like using a lens with a focal length 1.5x longer than the actual focal length of the lens on the camera. So, if you had a 50mm lens on your film SLR and put it onto your dSLR, you will see a more restricted angle of view that corresponds to something like a 75mm lens. This only becomes significant if you have an existing collection of lenses from one maker that will also fit your prospective new dSLR and you wish to use them. Wildlife photographers love the crop factor because their 300mm telephoto becomes, in effect, a 450mm telephoto while landscape or architectural photographers become upset that their 24mm wide-angle has now become a not-so-wide 36mm lens in effect. They then have to buy an expensive 16mm lens (or thereabouts) to be back their 24mm angle of view.

    Kit Lens vs Standalone Lens
    dSLRs are expensive (but prices continue to fall) and, traditionally, have not included a lens because there are so many to choose from and may well be bought by an enthusiast with an existing and compatible lens collection. However, as dSLR prices fall, many manufacturers now include a short-range zoom lens (2x - 2.5x) as a general-purpose starter lens for those venturing into SLR photography for the first time. These lenses have a focal length range of 18-55mm or so. These are specially designed as starter lenses for the dSLR market and are often included in kits for very little extra money compared to the camera body sold alone. These lenses represent excellent value for money and under many conditions produce quite acceptable results. However, some people may observe limitations in the performance of these lenses as they start to become more serious about their photography. Remember that the dSLR is an enthusiasts camera and to buy quality lenses, you will be spending as much, or more, as the camera body on its own (and even more over the months and years as the photography bug bites and you want more lenses).

    Nikon vs Canon vs Sony vs Pentax vs ...
    Many people wonder which make is the best. The short answer is that none of them are (or all of them are, whichever way you wish to look at it). No major manufacturer makes a bad camera and every maker sells different models throughout the world. What's best for me may not be best for you and vice versa so how do you choose? Well, once you have narrowed down what you want (see here for further advice) go to the stores and handle these cameras. One person may prefer the control layout over another and somebody else may prefer the menu displays on one camera over another and so on. We are all different and have our own personal likes and dislikes. Somebody else cannot make your mind up for you - only you can do that. Asking for the opinion of others over whether you buy x or y may well give you 10 users saying why they bought x and 10 why they bought y. Work out what is important to you and decide what you prefer.
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