Part
7 Understanding the basics
How can we take better pictures?
In order to take crystal clear images, just like a professional photographer, we have first got to understand the basic principals of photography whilst grasping the fundamentals to the inner sanctum
and dynamics of how the camera functions in various environments.
Okay, so lets recap and recover some common ground again. So that we have not left any thing out.
What is depth of field (DOF)?
Depth of field is the distance wherein subjects are in focus, technically this is when the subject is in focus and all other objects at the same distance are also in focus. Objects some distance in front of and behind are out of focus.
What affects depth of field?
What will affect your depth of field when you try to capture an image. The following three principals
are used by many photographers.
Distance from subject
Focal length
Changing the lens aperture
The aperture is basically the size of the opening that allows light to go through the lens. This is expressed in f/stops (aperture values), given the range from max (large at f/2.8) to minimum (small at f/8).
Put simply:- a small f/value (f/2.8) indicates a large aperture.
A large f/value (f/8) indicates a small aperture.
Thus a large aperture gives a shallow depth of field, and a small aperture gives a great depth of field.
So if you only want the subject the lens focuses on to be sharp and every thing in the back ground to be out of focus as in the case of a portrait where by the back ground is slightly blurred. Then a large aperture would be used.
If you require all of the details in the ground and fore ground to be in focus, a small aperture would used.
But I have a digital camera and it is hard to estimate the scale of aperture to use. Easy, no worries!
Digital cameras have a Portrait and landscape scene mode. Manual manipulation of the settings will allow the aperture f/value to be adjusted and previewed on the LCD screen.
Mmmmmm! large, small and f/ values, aperture I’m lost. I just wanna take pictures of castles and baby kittens. Don’t worry. I have written a step by step technical guide out lining the basics and more advanced steps required to get your head around these important terms whilst putting them into day to day practical examples. Changing the focused distance.
When a photographer focuses on a subject close to the camera, the depth of field is less than when you focus on the subject further away from the camera. It is not the distance of the subject from the camera that is critical for depth of field, but the distance at which the lens is focused. Example:- Three people standing at the same distance behind each other. Now focus on each individual face. Notice some thing different in each picture capture. I hope you do. Each face at different distances are either in focus, blurred or just unrecognisable. Reminder:-
the key to a good theoretical EXPOSURE = Aperture + Shutter speed
Changing the focal length.
This is the distance between the optical centre of a lens and its focal point. In practice, the focal length is a measure of the magnification and angle of view of a given lens or zoom setting. Okay so lets look at this in a more practical sense. Lets say we have a beautiful, I mean a drop dead gorgeous, a real stunning topless model standing in the studio 3metres (10ft) in front your camera. You are using a 28mm lens and a small aperture value setting of lets say f/22 & 1/125. You will notice that the depth of field in front of and behind the model is in perfect focus. Almost crystal clear. Okay, you change lens and try a 70mm lens with the same small aperture value setting f/22 & 1/125. You will notice that the depth of field has been restricted using this longer lens and that sharpness extends from around 2m to 5m from the camera. And even if we change lens again, this time to a 135mm lens at the same small aperture setting of f/22 & 1/125. You will notice now that the background scenery and objects behind the model are out of focus. The depth of filed in this case extends from around 2.5m to 3m from the camera.
©Eugene Struthers 2007 ©Glamour
Photo OnLine 2003
Lens aperture 
Aperture
value(s):
f/64, f/32, f/22, f/16, f/11, f/8.0,
f/5.6, f/4.0, f/2.8, f/2.0, f/1.8/f1.4 etc. (WE ARE HERE)
Control via
the lens section
Shutter
speed(s):
1/8000, 1/4000,
1/2000, 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1 sec, etc.
Control via
the Camera section