Relation of Aperture to Exposure
Aperture regulates the amount of life coming to the camera sensor or film. The bigger the opening ( aperture), the more light coming in and the smaller the opening the less light coming in. If you have an overexposed picture, you can get a properly exposed image by using a smaller aperture or F-stop like F8, F11, F16. Large apertures are 1.8, 2.8. Medium size apertures are F4.0, F 5.6.
WHEN TO USE THESE APERTURES ( F-STOPS)
Definition – Aperture is expressed in F stops . The amount of light coming to the lens is determined by the size of the aperture of the lens iris. The bigger the aperture F stop ( lens opening ), the more light comes in. the smaller the aperture, the less light is admitted . F1.8 is a very big lens opening versus F11.0 which is a smaller opening. Each lens has a maximum & minimum aperture. The best lenses ( and more expensive quality ) have large apertures ( F stops ) like the 50mm 1.4 portrait lens, the 85mm 1.8, 200mm 2.8 lens.
F1.8- F2.8 – Great for shooting portraits, fashion, sports, and macro shots with shallow depth of field. Shallow depth of field mean background behind the subject matter is out of focus or blurry. Fast lenses with F1.8 and F2.8 are great for getting rid of clutter in the background & creating good bokeh. These apertures are great for shooting in low lighting conditions.
F4.0- F5.6 – Good for medium portrait shots or telephoto taken with a prime or telephoto zoom lens ( like Canon’s 70-200mm F4). At these apertures, with a good telephoto, you can still shoot with a good background blur, Longer telephoto lenses at 5.6 still produces a good background blur depending on lens quality.
F8.0 – This is the sharpest F-stop in any optical camera lens for shooting film or digital. This aperture produces the a very good depth of field esp. in wide angle lenses ( 11-24mm )and normal lenses ( 50mm ) for full sensor digital cameras. Practical aperture to use in flash photography at events and weddings.
F11- F22 – These F stops produces very high depth of fields in wide angle, normal, and short telephoto lenses. To get the best resolution in digital., shoot at F11.0 or F16. Best resolution for shooting landscapes