CAMERA BASICS

Aperture (Av): (def.) - Hole/opening that varies in size (depending on how much light it is required to be let through).  It is controlled by a mechanism called the "Iris Diaphragm", which allows more control than in the past.  F. Stop is the term used to describe the size of the hole.

Smaller aperture sizes such as f/22 let in less light and allow for a greater depth of field (more of the shot will be in focus), whereas a larger aperture size such as f/1.4 will let in MORE light but will have a much shorter depth of field.

ON MY CAMERA (Canon EOS 400D), these are the Aperture Sizes available with the Kit Lens (smallest to largest hole):

f/29< f/25< f/22< f/20< f/18< f/16< f/14< f/13< f/11< f/10< f/9< f/8< f/7.1< f/6.3< f/5.6< f/5< f/4.5< f/4.0


Shutter (Tv): (def.) - Mechanism that begins and ends the exposure.  Different speeds let in different amounts of light and are usually expressed in seconds or fractions of a second.  
There are 2 different kinds of shutters: Focal Plane Shutters, which operate directly in-front of the film/sensor, and BTL (leaf) shutters, which operate inside the lens much like a diaphragm.

ON MY CAMERA the shutter speed times are as follows:

30"> 25"> 20"> 15"> 13"> 10"> 8"> 6"> 5"> 4"> 3.2"> 2"5> 2"> 1"6> 1"3> 1"> 0"8> 0"6> 0"5> 0"4> 0"3> 1/4> 1/5> 1/6> 1/8> 1/10> 1/13> 1/15> 1/20> 1/25> 1/30> 1/40> 1/50> 1/60> 1/80> 1/100> 1/125> 1/160> 1/200> 1/250> 1/320> 1/400> 1/500> 1/640> 1/800> 1/1000> 1/1250> 1/1600> 1/2000> 1/2500> 1/3200> 1/4000>

Exposure: (def.) - Total amount of light captured:

                Exp. = Time (shutter speed) x Intensity (aperture size)
                   = Tv x Av

HISTORY OF THE CAMERA

1267 - ROGER BACON (english photographer) writes about the "camera obscura" as depicted by 10th century writings of arab scholars. 

Camera: (lat.) "vaulted room" 

Obscura: (lat.) "Darkness" 

1490 - LEONARD DI VINCI (artist) describes the room in detail.

A Camera obscura was a room what was very dark with a primitive lens on the top which projects an image (using mirrors) onto a concave surface.  It was originally used to see what was going on around the towns they were erected.  See - Jerez, de la Frontera in Spain. 

1557 - GIOVANNI BATTISTA DELLA PORTA suggests its use as a drawing aide, and the first movable camera obscura appears. 

1676 - First reflex mirror camera produced. 

1685 - First Telephoto lens produced. 

1826 - First Permanant captured image in recorded history taken by JOSEPH NICEPHORE NIEPCE.  It was an 8 hour exposure, created with Bitumen of Judea on a Pewter Plate.  It was the view from his bedroom window.  The process he used (Heliography) has now been recorded as the first successful example of what we now call photography.

Later on, Niepce's collaborator LUIS DAGUERRE continued the work mapped out by Niepce and created what would become known as the "Daguerrotype", a style of photography common in the early 1800s.