Aperture

When the shutter release button of your camera is pressed, a hole opens up that allows your camera's image sensor to catch a glimpse of the scene you want to capture. The aperture that you set impacts the size of that hole. The larger the hole the more light that gets in – the smaller the hole the less light.

The aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or image sensor. In combination with variation of shutter speed, the aperture size will regulate the film's or image sensor's degree of exposure to light. Typically, a fast shutter speed will require a larger aperture to ensure sufficient light exposure, and a slow shutter speed will require a smaller aperture to avoid excessive exposure.



f /2.8

The Depth of Field is the distance wherein objects are in focus.When you desire a great depth of field, where objects both close to you and far from you are in focus select a small aperture.The photograph appears in crisp focus. And when want to isolate your subject, as when you are taking a portrait and want your subject to be in sharp focus but the background to be out of focus you use a shallow depth of field where in a large aperture of small f/value or small aperture value is used. 

f /22



Reducing the aperture size increases the depth of field, which describes the extent to which subject matter lying closer than or farther from the actual plane of focus appears to be in focus. The larger the diameter of the aperture, the more light reaches the film / image sensor. Aperture is expressed as F-stop, e.g. F2.8 or f/2.8. The smaller the F-stop number (or f/value), the larger the lens opening (aperture).

~ Hari Bhagirath Photography