Of F Stops and Apertures

Photography is described as an art of capturing light. Now the amount of light captured on your photos which directly corresponds to the quality of photos depends on three fundamental parameters: how fast the shutter closes (shutter speed), how wide the shutter opens (aperture) and how sensitive the image sensor is (ISO). Having already known a bit about the shutter speeds, in this blog post we shall discuss the intricacies involved with the size of the opening.

Aperture is defined by a term called f/stops in photography parlance. The smaller the f/stop number, the larger the opening (like an f/1.6) and larger the number (like f/16) smaller if the opening. Just remember that it’s the denominator that we are looking at so the size of the opening would be converse of the magnitude of the denominator.

Now aperture has a great bearing on the depth of field of the images that you capture. The larger the opening, the more light can get in, and the more blurry the background, or lesser depth of field. Conversely the smaller the opening, lesser light enters and more sharper the background, greater the depth of field. Depth of-field is a term that describes the area from near to far that is in focus; in other words, it describes how much of the image is in focus. For more on Depth of field, read a previous post on YouCanClick.Com here.

In brief, just try to remember this table. Don’t bother if you cant because this will come to you naturally when you start taking photos.

Larger f Stop(like f/1.4, f/2, f/2.8)	Smaller f Stop (like f/4, f/5.6, f/8, f/16)
Smaller Opening Sharper Image Background Greater Depth of Field	Larger Opening Blurred Image background Shallow Depth of Field

Just to illustrate the above, have a look at the two images here. Both were taken at approximately the same time with a hand held camera with two different f stops (one large and another one small). Do you note the difference in the depth of field that change in f stop produces. While in one image the tree in the background is totally blurred, the other image has a sharp outline of the leaves on the tree.

Furthermore, because a smaller opening requires that the lens be open longer to get the same amount of light as a larger opening, an image has an increased chance of being blurred if the camera or the subject moves during exposure. In this case, a camera support like a tripod would be recommended. So, the trick is to get the proper depth-of-field and the desired degree of image sharpness with the available light.

To conclude Larger aperture numbered (f/8.0 or f/11.0) result in more depth-of-field than smaller aperture numbers (f/2.8 or f/4.0). Longer shutter speeds (1/60th or 1/30th) are more likely to be blurred than shorter shutter speeds (1/250th or 1/400th). When shooting low-light scenes, increasing the ISO setting (say, from 50 ISO to 200 ISO) allows the image sensor to capture more light more quickly, allowing the use of a faster shutter speed, or a smaller aperture setting. But this increased ISO setting increases the amount of digital noise. These are the fundamental trade-offs of all cameras, film or digital.

Take home message: To add ‘depth to photos’ reduce the aperture..

Happy Clicking!!

The Guild