1. What is Aperture:
An aperture is generally a hole or an opening through which light travels. In the case of mobile phones or DSLRs it the lens through which light travels. And in case of our eyes, it is a pupil through which light travels so here pupil acts as the aperture.
All cameras that we know of are designed like human eyes. The sensors in the cameras work just like retina in our eyes. But the amount of light which enters the retina is limited to the size of the pupil, so the larger the pupil the more light enters the retina.
2. Large vs Small aperture:
The size determines how collimated the light rays are (Collimated light is a light whose rays are parallel). So narrow size results in a sharp image because it admits highly collimated rays. While its wider size gives an image that is sharp only for objects at a certain distance.
In photography, the aperture is expressed in terms of “f-numbers” commonly known as “f-stops” (for ex.- f/2.0) which describes its various sizes. A larger f-stop means a smaller aperture while smaller f-stop means a larger aperture. The size of also determines something called “Lens Speed”. So maximum aperture (of sizes f/1.4 or less) lenses are considered as “fast lenses”.
3. The depth of field:
The depth of field refers to the area of the image which appears to be sharp. Smaller or narrower apertures give images with sharp foreground objects and a blurry background. While larger or wider one provides images with both foreground and background objects in focus.
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