subject: How To Make Proper Use of Lens Apertures [print this page] How To Make Proper Use of Lens Apertures How To Make Proper Use of Lens Apertures
The diameters of all digital SLR camera lenses are controlled by a metal-bladed iris. The size of the iriscan be regulated by the image taker using the standard aperture range, which begins at 1 - the biggestdiameter - and gradually becomes smaller on a logarithmic scale that is based on the square root of two.
The idea is to make use of an aperture with a shutter speed that yields the right exposure. Luckily, withtoday's digital SLR cameras all you have to do is to decide on the relevant aperture size and the camera'selectronics can decide on the right shutter speed to produce the appropriate exposure.
This will occur on a digital SLR camera that is set to aperture priority mode. If you aspire to become creativeyou can put your digital SLR camera in manual mode and simply select the required aperture and the shutterspeed. But you have to be careful here by selecting the shutter speed first, and then decide on theaperture. If you do it the other way around, it might not work.
You have to understand that when choosing sizeable apertures you will generally obtain photographs that havea minimal depth-of-field. This means that the background, and at times the foreground of a subject, will notbe in focus. This effect is superb for portraits and when you do not want any distraction in a scene.
If you require more of the photograph to be in focus you will have to go for a smaller aperture.Unfortunately, a smaller aperture will mean less light entering the lens and thus the shutter speedwill be by design reduced to preserve a reasonable exposure.
A longer shutter speed means that there is greater risk of experiencing camera shake, which can lead toblurring. It is a delicate balancing act actually. You either reduce the depth-of-field to acquire thedesirable exposure, or you experience blurring because there is insufficient light.
Nevertheless, there is a smart way to circumvent this drawback. In order to lessen the probability of imageblurring, all you have to do is to put your camera on a bean bag or a tripod, then utilize a remote releasecable or the camera's self-timer to minimize unwanted camera movement, and that is all there is to it.
Lens apertures are actually ratios of the lens's focal length and are given as f/numbers, like f/3.5, f/8,f/22, etc. These are also referred to as f/stops, or simply stops. The bigger the f/number, the smaller isthe aperture. So an aperture of f/20 is considerably smaller than one of f/3.5.
