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| Page Views: 2,852 | A Photography Primer by phil_uk_net - last update: Nov 29, 2003 |
1. Introduction I've been meaning to write something along these lines for a while but other activities have got in the way. The objective is to provide some basic pointers to those who have none or very little experience of photography. It may be of use to someone who has been using a 'point-and-shoot' camera and is taking the first steps towards Single Lens Reflex (SLR) photography. What I pen below will also expose (no pun intended) my own limited knowledge of photography but I am getting too old now to care about such vanity. I will cover some basics to begin with before going on to talk about equipment and techniques. To finish off I will briefly cover the relatively new area of digital photography. This is a first draft and if I feel so inclined I may write some more. Depending on the feedback, if any, I may even remove it all together. I will be more motivated to write more if I am made to think it is actually of any use to anyone. Any comments or constructive criticism are welcomed. The photo. Canon T90, Canon 70-210mm/F1:4 lens, ISO 100. Exposure details not recorded This photo gets favourable comments but it is nothing special technically. A lot of luck was involved. I just happened to have my camera ready when this monk decided to use his at the Grand Palace in Bangkok. |
2. The Basics Up until quite recently, with the advent of digital photography, the basic concepts of photography had not changed for a hundred years. Reflected light from a subject falls on to a light sensitive medium where it creates an image. The image can be transferred on to paper or projected using a light. The earliest types of camera were just enclosed boxes containing photographic film with a pin hole that was uncovered for a pre-determined time to allow light to enter the box and form an image on the paper. As mechanical and electrical technology improved through the 20th century cameras have become more sophisticated in the manner that they allow light to fall on the film, and how lenses focus etc., but the principles remain the same. Digital photography has changed much of the process but the concepts of optical laws and exposure remain the same. The photo. Canon T90, Canon 70-210mm/F1:4 lens, ISO 100 Exposure details not recorded Walking around carrying a camera, I am always on the lookout for an interesting subject and this Chinaman caught my eye at the Central Market in Kuala Lumpur. |
3. Exposure Exposure refers to the amount of light that is allowed inside the camera when taking a photo. It is governed by two factors. i) Aperture. An aperture in the lens changes in size in exactly the same way that the iris in our eyes changes size to adjust for varying amounts of light. Just as our pupils dilate in low-light conditions the lens aperture will open up when there isn't much light around. The size of the aperture is expressed in numbers known as F-stops such as F2.8, F4, F5.6, F8, F11, F16, F22 etc. An aperture of F2.8 will allow twice as much light into the camera as an aperture of F4. An aperture of F4 will allow twice as much light into the camera as an aperture of F5.6, and so on. ii) Shutter speed. A shutter in-between the film and the lens opens to allow light on to the film. Obviously the longer the shutter is open for, the more light will be allowed in to the camera. A shutter speed of 1/500 of a second allows in twice as much light as a shutter speed of 1/1000 of a second. Correct exposure relies on getting these two factors right. Depending on your camera, both can be controlled manually by the user or both can be set automatically by the camera. With many cameras it is possible to select one manually and the camera will automatically set the other to give correct exposure. The photo. Canon A1, Canon 70-210mm/F1:4 lens, ISO 100 1/1000s F4.0 I spotted this man harvesting pineapples in Phuket, Thailand. My camera was set on shutter speed priority at 1/1000 athough there wasn't enough light for this shutter speed. The aperture opened up to its maximum F4 for the lens but the camera was still complaining of under exposure. Fortunately my focussing was good and the large aperture has caused the bacground detail to be blurred nicely. |
| Petronas Twin Towers, Kuala Lumpur |
4. Measuring light / effects of camera settings In the early days photographers measured the amount of light falling on the subject they were photographing with a hand held light meter. When they had the reading they would manually set the controls on their cameras to get the right exposure. These days, almost all cameras have built in metering systems that measure the amount of light reflected from the subject, so external light meters are not really necessary. Exposure control gets a little complicated because the amount of light in different parts of a scene varies. Most cameras use a centre-weighted average metering system which means basically that the exposure settings concentrate more on what is in the middle of the viewfinder. The camera manufacturers have devised extremely complex algorithms measuring different points in the scene to try to work out the optimum exposure. Because the shutter speed and aperture can be set independently, in most cases, it is possible to set different permutations of both to get the right exposure setting. For example, 1/250 of a second and F5.6 lets in the same amount of light as 1/125 of a second and F4 or 1/500 of a second and F8. So, what's the difference? An image is recorded all the time that the shutter is open so faster shutter speeds freeze action whereas slow shutter speeds result in blurred images. For fast action where a sharp image is required it is necessary to shoot at fast speeds. On the other hand, to create a blurred image to give the impression of speed or to soften a waterfall, a slow shutter speed might be preferable. Altering the aperture affects the Depth Of Field (DOF). If you focus on something in the distance the object you are focusing on is in perfect focus. However, there will be a distance before and beyond the object that is also in focus and this total distance is known as the Depth Of Field. For some pictures where you want everything in focus you need a deep Depth Of Field. However, for certain kinds or portrait photography for example you may want a shallow Depth Of Field. This way, the subject will be in sharp focus but everything else will be blurred thus accentuating the subject. These are important considerations when selecting which settings to use. The amount of light required is also governed by the speed of the film, specified by the ASA number. Film with a higher ASA is more sensitive to light so requires less of it. This means that ASA 400 film is more suitable for low-light conditions and shooting indoors without a flash unit. The downside with higher ASA rated film is that it is more 'grainy' so less suitable for producing large size prints than lower rated film. It is also more susceptible to damage in airport X-Ray machines. The photo. Canon T90, Canon 28mm/F1:2.8 lens, ISO 100 Exposure details not recorded When composing a photo it is sometimes a good idea to include some detail in the foreground to add interest to the main subject. The much photographed Petronas Twin Towers in Kuala Lumpur are quite boring on their own but I thought that this tree improved the composition. A wide angle lens and a small aperture will ensure that everything remains in focus. |
5. Basic equipment and photo taking secrets Does it mean I need a really fancy camera and one of those huge lenses to take good photos? Definitely not, and there are no real secrets. I maintain that good photography relies about 10% on equipment and technique. The most important thing is imagination and there is also an element of luck involved. The more expensive cameras probably increase the amount of useable photos that you take. Complicated metering/exposure and auto-focus systems mean that every time you click the shutter there is a better chance that the photo will turn out right but if you understand your own camera and its imitations you can avoid these pitfalls anyway. Huge lenses are usually reserved for special conditions such as sports photography in low light and can be difficult for amateurs to use. The optical shortcomings of standard lenses over very expensive lenses with high quality optics will only be noticed when photographing special test patterns and zooming into the smallest detail. Camera Body The first thing is a good camera body that allows the user to control different aspects of metering and exposure. Most photographers have their own favourite brand (mine is Canon) but all of the big manufacturers make quality products and there is little between them. Lenses One of the main advantages of SLR cameras is that lenses can be interchanged, which means being able to select the right lens for the right situation. Some lenses are very specialised to the extent that they are not suitable for general photography. Zoom lenses are popular these days because they offer a range of focal lengths in one lens. I have travelled a lot with just a 28mm prime lens and a 70-210mm zoom lens and this combination has been adequate for the majority of situations. The exception was on safari in South Africa when I also took a 300mm prime lens and 1.4x teleconverter but this was an exception and not the norm. Lenses with greater focal lengths (telephoto lenses) have a narrower field of view and are therefore more suited for taking photos of objects at a distance. Wide angle lenses have a wide field of view and are more suited for panoramic scenes. They are also useful indoors when it is not possible to increase the distance from the subject in order to increase the field of view. There are other differences though between lenses with different focal lengths. Perspective is one. Imagine a scene with an object in the foreground and an object in the background. Using a wide angle lens to take a photo of this scene would make it look as if there was a great distance between the two objects whereas a telephoto lens woud dramatically decrease this perceived distance. The depth of field is another factor that changes with lenses of different focal length. Telephoto lenses have a very narrow depth of field so accurate focussing is important. On the other hand, using a wide angle lens will result in amost everything in the scene being in focus as these lenses have a wide depth of field. Above 200mm lenses can get a little tricky to use, especially if they are hand held. The rule of thumb is to use a shutter speed faster than the reciprocal of the lens length. Therefore, a 200mm lens shoud not be hand held using a shutter speed of less than 1/200s which, on most cameras, would be 1/250s. The photo. Canon A1, Canon 28mm/F1:2.8 lens, ISO 100 Exposure details not recorded These young lads in Havana, Cuba were having fun jumping into the sea. A fast shutter speed freezes the action so the boy oos as if he is suspended in air. |
6. Digital Photography In the digital age, digital cameras seem to have taken off more than any other digital device. Instead of using photographic film, digital cameras use a light sensitive electronic sensor to convert the light into digital data where it is stored on an internal memory card. Apart from that, many of the photographic principles still apply. The advantages are obvious. i) With our desire for instant gratification it is possible to see photos straight away and bad ones can be deleted. ii) Captured images are already in a format where they can be sent in e-mail or posted on the Internet so there is no need to scan in photos. iii) After the initial investment in equipment there are no ongoing costs for film and developing. iv) The final result of the photo does not rely on settings made by whoever is doing the developing. There are some disadvantages though. High quality photos are large in terms of file size. Storing photos will require investment in computer storage equipment instead of the shoe box that you might have stored your film negatives in. Obtaining prints will require buying a suitable printer or paying a photo shop. Prints from digital film do not last as long as prints from traditional film but the technology is steadily improving. There are rumours that the sensors inside digital cameras will not last indefinitely but have only a limited life although I'm not sure if there is any truth in this. The photo. Canon T90, Canon 70-210mm/F1:4 lens, ISO 100. 1/180s F4.0 A telephoto lens allows the photographer to remain at a distance from the subject for portrait photos which results in more natural looking photos. Using a large aperture reduces the depth of field so that the background becomes blurred and attention is focussed on the subject. |
| Mermaid, Phi Phi Island (underexposed image) |
7. Digital cameras, resolution & the 1.6 factor What resolution do I need? Digital cameras are described by the amount of Megapixels they produce. Does this mean more Megapixels is better? Technically yes, but depending on what you will be using the camera for you may not need a high resolution. Digital images consist of thousands or millions of tiny dots. The total amount of 'dots' or pixels (short for picture elements) determines the Megapixel size. My Sony camera at maximum resolution can take images measuring 2048 x 1536 pixels which is just under 3.2 Megapixels. Taking a picture this size though to be used on the Internet would be a bad idea. Downloading a picture this size over a modem would take about 15 minutes. Secondly, most computer screens only display about 72 PELs (picture elements) to the inch so this size image would measure roughly 28 inches across. Therefore with even a large monitor it would not be possible to see the whole image with scrolling across. The advantage of high resolution is that small portions of an image can be 'cropped' and the crop will still be reasonable quality. If you are taking photos to be printed on a high quality printer that has a resolution of several hundred pixels to the inch that would be another reason to buy a high resolution camera but make the decision based on your needs and remember that high resolution means big file sizes which means higher storage requirements. Canon make very expensive professional cameras that have sensors of between 11 and 12 Megapixels. These sensors are the same size (36mm x 24mm) as conventional film. These cameras have no effect on the focal length of lenses used on them. However, the 'Prosumer' cameras Canon produce for the amateur consumer market have cheaper, smaller sensors or around 6 Megapixels. This resolution is more than adequate for most users but the smaller sensor has an effect on the lens optics. The focal length of any lens used on one of these cameras is magnified by 1.6 times so that a standard 50mm lens becomes 80mm. This is great for telephoto purposes as a 200mm lens becomes 320mm and there is no trade-off in speed. The downside with the magnification factor is wide angle. For some time now I have been using a 28mm lens as my standard lens but to get an equivalent lens for a digital SLR means using a 17.5mm lens. This is getting into the realms of super wide angle though and once in this territory lens prices get expensive. To everyone's surprise, Canon recently announced a digital SLR under 1000 USD. What's more, in kit form it comes with an 18mm - 55mm zoom lens that, on this camera, is roughly equivalent to the popular 28mm - 90mm zoom lenses found in many conventional SLR kits. It will only fit on this camera though and not any other in the Canon range such as the 10D. Any other Canon lens will fit on the 300D. What will happen in future is a bit uncertain. Nobody seems to be sure whether the price of cameras with full size sensors will come down so that a 50mm lens is actually a 50mm lens or if the manufacturers will continue with the smaller sensor format and start producing cheaper wider angle lenses. If your camera does not have a built-in flash unit, or even if it does, an external fash is always useful, not only for poor light conditions but also for fill-in flash situations. Remember that a flash unit works by bouncing light off the subject and using the reflected light for the photo. Many flash units are only suitable for use with subects that are 6 - 10 feet away. Bear this in mind next time you are at a sports stadium or concert hall and see lots of flashes going off - they are totally ineffective in this type of situation. The photo. Sony DSC-P1 1/1354s F5.6 ISO 100 No flash Photographing a subject against a bright background often fools the camera. The camera adjusts its settings for the whole scene but the main subject is actually underexposed. There are a couple of different ways to overcome this. One way is to take a meter reading off the subject and set the camera accordingly. This however will result in the bacground being overexposed. |
| Mermaid (corrected with fill-in flash) |
8. Me and photography My parents bought me a Canon A1 camera for my 21st birthday (many centuries ago when dragons, witches and warlocks roamed the earth. Yes, I'm old - just ask Annathrax). At the time, auto-focus cameras were in their infancy but not widely used. With the AE-1 (approx. 1976), Canon had introduced the first mass-produced, electronic camera, together with an extensive range of FD manual focus lenses. The A1 was about the best amateur camera available back then and a good tool to learn some basics with. Flexibility was the A1's strength as it could be operated fully automatically, fully manually or in a variety of semi-automatic modes. Over time I built up a system of lenses (50mm/F1.8, 70-210mm/F4, 28mm/F2.8, 135mm/F2, 300mm/F4, 500mm/F8 reflex, 1.4x teleconverter), some dedicated flash guns, spare bodies and accessories such as autowinders and a radio-controlled shutter release. My final acquisition in the Canon manual focus range was a T90 body which is often referred to as the best manua focus camera ever produced. I read photography books and used my equipment to put the theory into practice which is a good way to learn. 19 years after this present from my family, another one arrived, this time a Sony DSC-P1 digital camera. The P1 was my first foray into digital photography. Since owning it I have learnt a little about digital cameras and also a little about post-processing with Adobe Photoshop. In the three years since I've had the P1 I have watched the price of digital cameras and memory cards fall dramatically. The camera has been a good learning exercise for me but now I have outgrown it. Having owned good SR film cameras for many years it frustrates me that I cannot control the Sony settings as I wish to. The lag between pressing the shutter and a photo being taken with digital point-and shoot cameras is also very frustrating. I have an underwater housing for the camera and fully intend hanging on to it to take underwater pictures while diving. However, with digital SLR camera prices falling I think the time is approaching very soon for me to buy one and retire my film equipment. I have been reluctant to do so up until now because of the investment I have made in it over the years but going digital makes sense, especially when I look at how I use photos. Typically in the past I have taken thousands of pictures on film and then selected the best ones to scan in an put online. The photos and negatives have then been put into storage never to see the light of day again. With the emphasis on taking photos predominantly for use online it seems to make sense to capture images in digital form in the first place. The other part of the equation is that with the availability of cheap computer storage and CD writers, storing digital images is no longer expensive or problematic. I've been researching digital SLR cameras lately. My preference for Canon leaves me in no doubt as to which manufacturer I will choose. The choice of model comes down to 2 at the moment but taking everything into consideration (price/performance/the 1.6 factor) and looking cosey at my own personal needs in a camera, I think that the 300D is the one to go for. Pease don't write to tell me otherwise because you're not me, OK? The photo. Sony DSC-P1 1/1229s F5.6 ISO 100 Flash A better way to correct the above problem is to turn on the camera flash so that artificial light from the flash unit 'fills in' the detai that woud normay be underexposed. The advantage with this method is that the bacground is still exposed correctly. |
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lindsey1511 Sat Oct 24, 2009 15:21 UTC
May I ask where can I read more about The Brahma Jati Rat horoscope? I would like to read more about Rabbit and Pig. Kindly share with me if you have the article. My email is lindsey@dearmagic.com. Thank u very much, Lindsey from Malaysia | marvelous_girl Sat Aug 29, 2009 15:01 UTC
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How's life in Brentwood. originally from Billericay, now live in Sydney, Australia. Nice plant. |
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