The Basics of Your Camera

Posted by Hillcrest Camera Club on Wednesday, August 18, 2010

The Basics of Your Camera


The advent of the digital camera has made it easier than ever to take photographs you can show to your friends without having to apologise for the poor quality, and yet how many of us really use these cameras to their full potential.

The purpose of this article is to give a little insight into what your camera can do and what those funny little signs on the circular dial actually mean and do.

It is important when buying a digital camera to understand the reason for purchasing. If you are looking for something to take happy snaps of the grandchildren then a camera of 2 million pixels is adequate. (Most cell phones these days have built in cameras of 3 million pixels). The more pixels the sharper the pic and the crisper the colours.

If you are looking at taking wildlife photos for publishing in the travel mags then you need a 6 to 12million pixel camera with interchangeable lenses. (Known as a Digital Single Lens Reflex)
 
Most of us grew up using film cameras and know that when buying a film we asked for a particular speed, be it 50ASA or 400ASA or something in-between. This number is the speed of the film. The lower the number the slower the film and the better the colours but the more light you needed to be able to take the photo.
(ASA = AMERICAN STANDARDS AUTHORITY)

Conversely, the higher the ASA number the faster the film, the grainier the photo but the less light you needed. So! If you wanted to take a photo on Durban beachfront a 12 noon on a bright sunny summer day you would have used a 50ASA film. If, however, you wanted to take a pic at 6pm on a dark overcast day in the middle of winter you would have used a 400ASA film.

Digital cameras don’t use film; they use what is known as a Sensor or a Charge Coupled Device that can be likened to an electronic film that is built into your camera. The “speed “ of this CCD can be “adjusted electronically” by changing (either automatically or manually) the ISO on your digital camera settings normally from 200ISO up to 1600ISO and above on really expensive cameras.
(ISO =  INTERNATIONAL STANDARDS ORGANISATION.)

The success of any photograph depends on the amount of light entering the camera and controlling for how long that light illuminates the CCD.

 


APERTURE

The AMOUNT of light entering the camera depends on the camera APERTURE setting.

Imagine a water tap that is just open and lets through a drop at a time. This can be likened to the SMALLEST APERTURE of your camera just letting in a small glimmer of light. If you now open the tap so as to double the amount of water coming out and then stop again then you can again liken this to INCREASING THE SIZE OF THE CAMERA APERTURE  BY 1 STOP so that double the light passes through. If you continue opening and stopping the tap each time the amount of water from the tap doubles and liken this to your camera then you now should have a good idea of how the amount of light is controlled.

On the camera, each “stop of the water tap” is know as an “f stop” and depending on the camera ranges from f2.8 up to f29. There is an inverse relationship between the size of the f stop and the amount of light passing through the aperture. At f29 the aperture is at its smallest and the minimum amount of light passes through. Conversely, at f2.8 the aperture is wide open and the maximum amount of light is allowed to pass.

 

 
SPEED

The length time for which the light falls onto the CCD is dependent upon the speed of the shutter. Shutter speeds range from seconds to microseconds

1…1/2…1/4…1/10…1/100…1/250…1/500…1/1000…1/2000…1/8000 +++

It is the interplay between the speed and the aperture that allows the photographer to achieve the desired results.

DIGITAL VARI-PROGRAMS


With digital cameras the manufacturers have taken away the need for knowledge of photography and instead have put pretty little icons onto the control dial to allow us to take reasonably good photographs every time.

The first is the AUTO icon that is normally green in colour.  This is Dummies 101, the camera does everything for you; it guesses at what it thinks you want to shoot, focuses, measures the light, sets the aperture and speed, you  just point and shoot . 99 times out of 100 you will get a reasonable picture.

It is important to understand, besides controlling the amount of light passing through, what the consequences are of selecting the various aperture settings. The aperture also controls the DEPTH OF FIELD. This is the area in front of the camera that will be in focus when the photograph is printed.

THE LARGER THE f STOP NUMBER, THE GREATER THE DEPTH OF FIELD


 


Running stick man  -  Camera sets a fast shutter speed, designed for action type of pic                                                                        where the subject is moving. E.g. sport / 4x4 events / wildlife.

Mountain Range  -  Camera sets a small aperture,  designed for pics where everything is in focus. E.g. landscapes /seascapes. (Large depth of field)

Mountain Ranges with Moon  -  Same as Mountain Range but camera allows more fill-lighting. Moonscapes /  Night scenes with artificial lighting such as street lights.

Lady with Hat  -  Camera sets a large aperture, designed for portraiture where just the face is in focus and everything else out of focus. (Small depth of field)

Flower  -  Camera allows close-up photographs of flowers / insects etc.

 


AUTO MULTI PROGRAM

In addition to the above ICONS, the modern digital camera allows more control over what the camera does using the P, A, S and M functions.


P        This allows the user to choose what combination of aperture and shutter speed to use to obtain the desired effect. The camera chooses the initial combination, the user can then rotate the control dial to get the result he wants. Irrespective of which combination is chosen the exposure is still the same.

A        The photographer sets the aperture he requires and the camera will automatically set the correct shutter speed. This allows the user to control the depth of field.

S          This is the converse of A. The photographer sets the desired shutter speed and the camera automatically sets the correct aperture. This allows the user to freeze an action shot.

M         This is the manual mode. It allows the photographer full control and full artistic licence as the user sets both aperture and shutter speed.

I hope this sheds a little light on the vastly complex subject of photography. Happy shooting.
Gordon Battersby



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