The aperture is one of the most creative tools you can ever master in your photographic journey. The aperture opening is formed by a set of diaphragm blades fixed inside a lens.
The opening can be adjusted by adjusting the F number in the camera settings, in turn, controlling the amount of light that hits the sensor. By adjusting the aperture opening we are controlling two things. One, the amount of light that hits the sensor.
Other being the depth of field which gets adjusted. The diaphragm blade comes in different numbers,7,9,12 and it goes on. Generally this number of diaphragm blades has a direct effect on the bokeh shape.
The depth of field is the image that appears in focus from the foreground till the background. If an image is having a great focus from the foreground till the background which is generally the case of Landscapes it is said to have a great depth of field. On the other end, if an image which is having a small portion in focus either in the foreground or in the background or somewhere in between, it is said to have a shallow depth of field, like in portraits.
Through aperture the amount of light is controlled and measured by using the term called F stop. A F stop is nothing but the relationship between the focal length and the aperture opening in mm. For example, a 50mm lens with an aperture opening of 10mm results in the Fstop value of F5.
There are few lenses which are called as Fast lenses. Fast lenses are nothing but having a low F number value. Which means, big aperture opening, which enables us to shoot in low light conditions. For example, a 50mm lens which has got a 41.5mm lens aperture opening. Which means, the F number is F1.2.
There is one last thing to know about this aperture. One is constant aperture, The other one is variable aperture. Constant aperture is nothing but this aperture value stays across the range. For example a 70-200 mm which comes with F number 2.8. The F2.8 can be achieved at 70mm as well as at 200mm.
Whereas if you take an 18-55mm kit lens, the F number comes at a max F number is 3.5 at 18mm. The maximum aperture at 55mm is F5.6.
I trust this blog helped you in understanding aperture much better and enables you to become more creative in your photographic journey.