Don’t worry about your pet tripping the infrared sensors in your home. The alarm companies will activate the “pet alley,” which is a few inches of undetected space that can be adjusted for your cat or dog. (It can be designed according to weight, say, less than 30 pounds.) Read the rest of this entry »
There are numerous detection devices available and choosing the right one to protect a particular area isn’t always easy. There is a whole range of circumstances to take into account — the size of the room, what’s in it, even how it is constructed, as well as what’s outside or even across the road.
You may need one or more types of detectors in any one area — for example, there are bound to be doors and windows to protect as well as the room itself. There may also be very large areas of glass, such as a patio door, draughts or heating, which may make it difficult to site certain types of detectors, and you may have pets in the house which will mean careful positioning and directing of the detection pattern. Read the rest of this entry »
There are no specific British Standards for control panels (or alarm devices themselves), although elements of BS 4737 relate to features found in alarm equipment. This is likely to change with the introduction of European Standards which will, for the first time, require individual components to meet levels of performance and construction.
It is very important to understand how an alarm system is operated if false alarms are to be avoided. To reduce this risk, manufacturers have been making instructions easier to follow and many panels now incorporate a Liquid Crystal Display (LCD) giving plain English step- by-step instructions to guide users through the arming, resetting and disarming procedures. Read the rest of this entry »
The extensive range of equipment available can prove very confusing. Your main aim is to find a system which is easy to understand, uses proven technology and can be extended, if necessary, at a later date.
Personal recommendation is probably the best way to choose a company to install your alarm system.
Then, if the installation or system should prove unsatisfactory, you do at least have an official organisation to approach to take up your complaint and investigate the situation.
You should obtain at least three quotes from reputable installers and remember — the cheapest may not necessarily be the best value. Read the rest of this entry »
The most important additions to the camera outfit are the extra lenses. If you have always used a standard lens on your camera, you may not find it easy to decide which would be the best lens to buy next. Obviously, you want to start with the one that will be the most versatile for your type of photography. As a first buy, most photographers choose a wide angle lens (28mm) or a telephoto lens (135mm). If you like taking scenic landscape pictures or you want to include a wide area without having to step back with the camera too much, then a wide- angle lens is a good choice. Read the rest of this entry »
The biggest attraction of a 35mm single lens reflex camera is its versatility. Not only is it a useful piece of equipment in its own right, but it can be the ‘heart’ of a complete camera outfit. You can add things like extra lenses, filters, a flashgun, a tripod, as and when you feel you need them, to help you get the results you want.
Smaller items—a blower brush for cleaning lenses, or a cable release, for example—also form part of the serious photographer’s equipment as the collection builds up. And, of course, you will need a gadget bag, or a carrying case to keep everything in. Read the rest of this entry »
The lens-to-camera attachment is very important on SLR cameras. It must be easy to fit, light-tight, and link up smoothly with the camera’s controls. There are two basic types of lens mount—screw thread and bayonet. Screw thread mounts: found on the older or less expensive SLR models. Their great advantage is standardization. All screw thread lenses fit any make of 35mm camera body made for this type of lens mount. Read the rest of this entry »
A camera which is reasonably compact, easy to operate, and can take a whole range of lenses opens up dozens of new possibilities for any photographer. Telephoto lenses for sports action pictures and better portraits, wide- angle lenses for depth in sweeping landscapes and pictures in cramped spaces, or close-ups of insects using a macro (close-focusing) lens. The pentaprism SLR camera can provide all these things. It is the most popular interchangeable lens camera, widely used by amateurs and professionals alike. There are others with interchangeable lenses—for example medium format SLR cameras and some viewfinder cameras—and these are discussed in detail later on. Read the rest of this entry »
Most modern cameras make it impossible to make a double exposure unintentionally. But sometimes double or multiple exposures provide unusual and interesting results.
A few cameras have a switch or lever to allow the shutter to be retensioned without advancing the film to the next frame. This makes accurate register of the subject components possible and gives the most successful multiple exposures. Read the rest of this entry »
Even the most accurate through the lens exposure meter can be fooled by a subject surrounded by large dark or light areas, subjects which are predominantly back lit, or those against unusual backgrounds. These can influence the meter, providing false information about the light level. Thus the main subject is over-exposed if the meter reacts to a large expanse of black background and, conversely, underexposure of the subject results if it is back lit or surrounded by a large bright area. Read the rest of this entry »
This is usually found on a camera top plate. The index shows the exact location of the film within the camera and thus enables accurate measurements and calculations to be made. It is most useful for close-up work when you may want to measure bellows extension or extension tubes to help you work out magnification and exposure. Close-ups are difficult to focus with a non-reflex camera because the focus cannot be checked through the viewfinder. Instead the distance from the subject to the film must be measured accurately. Some cameras which do not have a film plane index have a serial number engraved on the top plate. The top of the figures often corresponds to the location of the film plane inside the camera. Read the rest of this entry »
When taking black and white infra-red photographs special focusing adjustments must be made because infra-red rays do not behave in the same way as visible light. The point of focus for infra-red radiations is further from the back of the lens than it is for white light, and a small degree of focusing compensation is necessary to produce sharp infra-red photographs. In fact the lens must be adjusted as if the subject were slightly closer. Read the rest of this entry »
Apart from the shutter release, film winder, focusing and exposure controls, even the simplest cameras have a few additional knobs and switches that are either safety devices or provide an extra degree of control. Used correctly they may not only make picture taking more reliable but can also increase the versatility of the camera.
Here’s how to use the extras most commonly found on modern cameras, and in some cases what you can do if your own camera lacks them. Read the rest of this entry »
When you buy from a trader who has called at your home without an appointment, you, have seven days in which to cancel the contract and reclaim the money you might have paid. This applies to goods you buy and to work you have arranged to have done, provided the sum involved is over £35. This law covers home improvements such as replacement kitchens or double glazing, but not new building work such as home extensions. If in doubt, contact the local Citizens Advice Bureau. Read the rest of this entry »
Exposure meters indicate light intensity and are designed to help you get a correct exposure every time you take a photograph. When a light reading is taken the meter indicates the correct adjustments needed to the camera aperture and shutter speed settings. This sounds simple, as indeed it is, but not all subjects can be treated in a straightforward way. How would you tackle a backlit subject, a snow scene or subjects in deep shadow, for example? In such situations your exposure meter can well mislead you into giving the wrong exposure. ‘Correct‘ exposures are a matter of interpreting meter readings and applying them to the subject in hand. Read the rest of this entry »
A few sophisticated automatic cameras have a dual metering system, one to provide guidance to the photographer in the form of a viewfinder exposure display, while the other system takes a reading of light reflected from the film plane during exposure. The Olympus OM2n is an example where CdS cells provide viewfinder information while silicon cells control the exposure when the camera is set to automatic. Read the rest of this entry »
Most modern cameras have a light meter built in. This has proved to be very popular among amateurs and professionals alike because of the speed and convenience it offers.
All exposure meters work towards the same end—to give the photographer exposure information—but the ways in which they operate vary widely. There are two basic types however: coupled and uncoupled. Examples of both systems are found in 35mm reflex and non–reflex as well as in smaller and larger format cameras. Read the rest of this entry »
You can measure the light either from the camera position or from close to the subject. The reading can be taken in two ways: using the light reflected from the subject or the incident light falling on the subject. Incident light readings can only be taken using a hand-held meter.
A reflected light reading, taken by both built-in and hand-held meters, measures the light bouncing off the subject. It can he measured either from the camera position, where you will actually take the photograph, or close to the subject. Taking the reading from the camera position will give an overall impression of the available light, including the background. But, if one part of the picture is more important than the rest, walk up to it and take the reading, or measure the light on a substitute. For example, a hand held close to the meter will represent skin tones in a portrait if similarly lit. Read the rest of this entry »
Choosing the best exposure for a picture is just as important as getting the image sharp. A beautiful holiday picture on the beach is spoiled if you cannot see details of the people in the photographs—they may be too light or dark.
A correctly exposed negative or slide will have a full range of tones from deep shadows to bright highlights. Under-expose your photograph and the darker parts of the picture will contain little detail; over-expose, and the bright parts will appear all washed out and lacking in detail. Read the rest of this entry »
Basically, there are two main types of shutter: those that work inside or just behind the lens, known as between lens shutters, including sector shutters; and focal plane shutters, which are positioned close to the film.
The between lens shutter closely resembles the aperture and is positioned between the lens elements, near the aperture blades. It is made up of two or more overlapping metal blades. which spring open for the time of the exposure and then close again. These shutters are very light and compact, and can synchronize with flash at all speeds. But between lens shutters have two drawbacks: few work at speeds of over 1/500, and they are costly to produce for cameras with interchangeable lenses. This is because each lens requires its own integral shutter and a separate means to block light from the film when the lens is removed.
Between lens shutters are used mainly on rangefinder 35mm cameras and roll film cameras. Read the rest of this entry »
