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Nov 28

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Photography basics – An introduction

You love taking pictures... whether it's with your mobile or your point-and-shoot. You take pictures of almost everyone and everything, your friends, family, strangers, food, flowers, toys, architecture, landscapes, etc. Some of your pictures, you really love.. and others are merely acceptable, whilst others you delete immediately. You realise that while you love taking pictures, some of your pictures are not turning out they way you expected them to. You feel that some of your pictures lack sharpness, or they're just too dark. Maybe the colours don't pop. Maybe you feel that your mobile phone or point-and-shoot is just too slow to respond. You explore your options, maybe upgrading to an advanced point-and-shoot or a DSLR. The shop you visit gives you a range of options, from sub compact cameras to full blow DSLRs. And that's when you realise that photography is quite a complicated subject. I've had quite a few friends come up to me asking questions like:
  • What's shutter speed?
  • What does f/1.8 mean?
  • What is bokeh?
So, in this series of short articles, I hope to explain what it all means.

The basic concept

Photography is essentially capturing light. Whether it is exposing a roll of film or a digital sensor converting light to digital information. In the early days of photography, images were captured in black and white on huge glass plates coated with chemicals. That evolved to colour film and now digital sensors. Feel free to read up more about the history of photography here. All cameras that capture photographs are considered still cameras. A still camera behaves almost exactly as the human eye. Like the human eye, the light enters the camera via a lens. The amount of light entering the camera is controlled by an aperture. In the human eye, that is controlled by the iris. The light's journey ends when it hits the camera's sensor or film. In the human eye, it ends at the retina. Like the human eye, images on the sensor are upside down. Digital cameras automatically compensate for this. Extending the human eye analogy, pixels on a camera sensor can be likened to the cones that make up the human retina. Unlike the human eye which constantly captures a stream of light information, a still camera's sole purpose is to capture a slice of time. In order to capture this slice of time, a shutter determines the amount of time the film or digital sensor is exposed to light. The shutter together with the aperture and mirror gives traditional DSLRs their distinctive clicking sound. The thing that comes closest to a shutter for the human eye is our eyelids. 🙂 Try opening and closing them real quick and you will see a series of still images.

Terms you will come across

Sensor - The sensor converts light to digital signals. Sensors come in various sizes, with point-and-shoot sensors being smaller than DSLR sensors. The larger the sensor, the cleaner the image. Which is why images taken using DSLRs always appear better than those taken with a mobile phone (which use the smallest sensors). This is beginning to change though, as a few point-and-shoot cameras now produce images that are almost as good as DSLR images. Megapixel - Many people assume that the larger the number, the better the image quality. Not necessarily so, if all you are after is printing to 8R, then all you need is 5 megapixels. If all you want is to share images on Facebook, then you'll realistically need much less. So don't get caught up with the megapixels race. It is more important that your camera's sensor is capable of producing clean, noise free images. Noise - Noise when used in digital photography refers to the tiny specks of red and blue you find on images taken in low-light situations such as photos taken in a dimly lit restaurant. The amount of noise increases as the sensitivity of the sensor is increased. ISO speed (sensor sensitivity) - For those of you who still remember film cameras, ISO is a rating that told you how sensitive a roll of film was to light. So a film roll rated at ISO100 is less sensitive than ISO400. All this means is that with ISO400 film, you are able to use faster shutter speeds that reduce the blur of movement. These days with digital, it's common to see DSLRs with up to ISO25600. But it's always better to stick with lower ISO values as they produce the cleanest, noise-free images. Camera lens - A series of glass / plastic lenses arranged in a multitude of ways that focuses image on the camera's sensor. Lenses can be broadly divided into two groups, zoom lenses and prime lenses. Zoom lens - Most cameras and DSLRs come equipped with zoom lenses. The reason for this is zoom lenses are versatile. Most zooms allow you to get up close to the action or go capture a group portrait. Typical DSLR camera bundles come with 18-55mm, 18-70mm or 18-105mm zoom lenses. Because zooms cater for a wide range of focal lengths, they are usually larger than the equivalent prime lenses. Prime lens - Prime lenses are lenses that have a fixed focal length. Prime lenses don't zoom. So if you have a prime lens attached to your camera, expect to move around alot more when taking photos. Focal length - Focal length determines how much an image is magnified on your camera's sensor. So, for example, a lens with a long focal length of 200mm will magnify a subject more than a 50mm lens. Focus - Adjusting focus on a camera is to ensure that the subject you are photographing appears clearly in the image. Remember when you were young and playing around with a magnifying glass out in the midday sun? If you held the magnifying glass a certain distance from the floor, the rays from the sun would converge to a single point. It's the same concept with cameras. Aperture - As mentioned above, the aperture controls the amount of light reaching the sensor. You will see numbers like ƒ/1.8 or ƒ/5.6, ƒ/1.8 is a larger aperture than ƒ/5.6. The larger the aperture, the brighter the image. The aperture and shutter go hand in hand to control the amount of light that reaches the sensor. Shutter - Like the aperture, the shutter also controls the amount of light reaching the sensor. The slower the shutter, the darker the image. The shutter and aperture go hand in hand to control the amount of light that reaches the sensor. Flash - A flash is a little bulb capable of produce a really quick burst of bright light. Flashes are used to help brighten up scenes, or to creatively light them. Antishake - Antishake is essentially the camera compensating for your movements. Antishake is called various things by the various manufacturers, ie: VR (Vibration Reduction - Nikon), IS (Image Stabilisation - Canon), SteadyShot (Sony), OIS (Optical Image Stabilisation - Panasonic), etc. The more shaky you are when you are taking a picture, the more likely your picture will be blurry. Antishake is supposed to help with that, but it isn't the solution to blurry images. Proper technique is still the best.

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