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Creative people will make creative photographers. The skills or craft needed to achieve their creativity is the conduit between mind and canvas. The synergy of creativity and craft make the masterpiece. Ergo, any good photographer will have mastered the craft of the camera. This article sets out to explain some very rudimentary technical issues concerning your use of a camera.
The transition between film and digital photography has been nothing but a wonderful journey for photographers. The explosion of technology in both hardware and computer applications has opened a plethora of knowledge need.
When discussing the basics of photography there are three subjects which need to be imparted: exposure, aperture and ISO (sensitivity)… I usually refer to this as the golden triangle. Today’s modern digital SLR cameras and most bridge cameras allow the user total control over this triangle.
People who grapple with cameras get to understand the need for correct exposure quite quickly. Fewer people get to grips with aperture priority though and depth of field that aperture controls. Opening the aperture limits the depth of field of focus while tightening the aperture brings items both far and near into focus.
Exposure and aperture choice are the single most important adjustments people make when creating a digital image. With today’s cameras it is often the case that where one setting is adjusted, the other changes too. They are easily controlled. Thus when you open up the aperture to a wider f-stop (say f/2 – f/5.6) the camera will adjust the exposure automatically to a faster speed, say 1/750 sec.
Often when you find you are in full control of your camera faculties, you face challenges with things which are outside your control… probably the most frequent being the available light. In the good old days of film photography the cameraman would choose the speed of the film, based on the purpose of its use. Film was rated by an ISO (or ASA) which was and still is the standard for light sensitivity for film, or as most referred to it as the speed of the film.
Today’s digital cameras have sensors to receive image light through the lens and enable its conversion to a digital format. Sensibly, manufacturers have chosen to hang onto the international standards for sensor light sensitivity, and they have given the user the ability to change the sensitivity of the sensor at any time. This control of sensor sensitivity levels forms the golden triangle of camera control.
Cameras may be set to operate with aperture priority or exposure priority (there are other modes) and, with the rolling of dials, either aperture or exposure speed is changed with ease. Adjusting the ISO on your camera may not be as simple as it should be. Lead manufacturers have come to realise a need to improve the ergonomics of ISO adjustment and most DSLRs allow a switch/button and dial adjustment right at your finger tips. Roll on the ISO dial in its own right.
So what? Why be confuse with this obscure concept? Well simply said, it happens to give you an extension of your potential. My passion happens to be wildlife photography and as many will know, perhaps the most successful time to dabble in image capture is during the earliest and last hours of the day, commonly known as the golden hours.
The earliest and very latest minutes of this range of light present one with challenges which can be met with that little adjustment of ISO for higher ‘gain’. There is conflict, for example, between your slowest exposure levels and capturing a moving animal, say at a predator kill, where it is sacrilege to use your flash!
You cannot allow movement blur… so you up your ISO to obtain a greater light gain, which will allow faster exposure, and thus sharpness. Simple! So, in the last few minutes of the day, you have no choice but to pump up the ISO.
Life is not a bed of roses, for there are sacrifices. When choosing a high rated ISO/ASA film for use, one knew that your images would be far grainier than the lower speed rated film. You would never choose a high ISO rated grainy film for landscape work (long depth of field/all in focus). The conversion to digital brought with it a conversion from high ISO film grain to high ISO digital noise.
Now, one could get extremely technical here and bang off a few terms which will mean little, perhaps. High sensor ISO settings are known to cause what is called the salt and pepper effect (resulting from photodiode leakage). Let us just call that a little colour distortion. You could observe the appearance of blues, where they should not be, or speckles of colour out of the general range. Just to complicate matters, the smaller the sensor size, the more noise is apparent (thus some mobile phones produce ‘grainier’ and more noise ridden images).
Noise reduction is a feature of many of the more advanced cameras. This is basically a set of algorithms which challenge the image noise while trying to retain or preserve low-contrast detail (possibly mistaken for noise). If the camera fails to achieve this, then the handy backup lies with excellent software applications which enable the photographer to adjust their images.
Take a good look at your camera… research the model you have, perhaps on the internet, and learn its ISO adjustment capability. Most compacts do not cater for this but both bridge and DLSR cameras do. You never know when that once in a life time opportunity presents itself at dusk or in low light and what a pity if you are still fumbling to find the adjustments.