When talking about photography there are a few key words that you should know as they will be used all the time by photographer. I for example will use most of the them in my blog posts.
SLR stands for Single Lens Reflex camera. These are cameras that typically use a mirror or prism system hence then name reflex from the mirror reflexion.
DSLR stands for Digital Single Lens Reflex camera and similarly to SLRs they also use a mirror but the film has been replaced by a digital sensor.
The aperture (in optics) is a hole or opening through which light travels. It is also called the Aperture Stop, f-number or f-stop (most common). See below for more details.
The f-Stop or f-number of a photographic lens indicates the size of the lens opening. The f-Stop is calculated by dividing the focal length of a lens by the diameter of the aperture when measured in millimeters. It can be adjusted to control the amount of light that will reach the sensor. The smaller the f-stop of a lens (always written on lenses in formats such as f2.8 or f2.8-5.6) the better it is as it will allow more light to go through. Large aperture such as f2.8 (or even better f1.2) will increase the depth (See below Depth of Field) of the photo and as a result the background will be very blurry compared to the point of focus.
Fixed & Changing Aperture Size
High quality zoom lenses will have a fixed aperture. For example f2.8. This means that if you zoom with you lens the aperture will not change and even zoomed out the amount of light getting through the lens will be the same. Entry level lenses will have changing aperture. For example f2.8 – f5.6. Meaning that when zooming out the aperture will go from f2.8 to f5.6 and as a consequence the amount of light going through the lens will be divided by two.
Depth of Field (DOF)
The depth of Field (or more commonly the depth) is the distance range between the nearest and farthest points that are in acceptably sharp focus. DOF can be altered by changing the aperture size, the length of the lens and the distance to subject.
ISO (Film Speed)
The ISO is historically the measure of the films sensitivity to light. Today it is used to increase or decrease the sensitivity of the DSLR’s Sensor. High ISO (1200 and above) will allow the photographer to take photos in low light condition but this will increase the granularity of the photo. Low is (100 and below) will allow the photography to do very sharp photos. It is always recommended to use the lowest possible ISO sensitivity on your DSLR.
The shutter speed will set for how long your sensor will be exposed to light. The slower the shutter speed the more the sensor will be exposed and allow to take a photo in low light condition. The risk with slow shutter speed is that the photo gets blurry if the camera moves just a little during sensor exposure.
Please let me know if there are other vocabulary in my posts for which you would like some explanation. I’ll complete this post with time.