If you’ve been following this blog recently, I explained what the whole deal was about the quintessential term APERTURE. If you need a refresher or want a hopefully simpler explanation than you’ve heard so far, do head back to the post: Technical Terms in Photography – Aperture.
Let’s see the difference visually. The three photographs are from my window and shot in sequence at the same time of day. I varied the aperture setting on my camera and the setting is shown on each photo.
The photo in the middle is typically as close as possible to a correct exposure. Most of the detail is visible and the colours are well balanced out. This was on a bright day at a medium size aperture, f5.6.
The photo on the top is an overexposure. This means that there is more light in the photograph than is necessary. The result is a washed out image as if the whole scene was enveloped in a mist. As can be seen, the details are suppressed and the colours are very light. This is at a very large aperture size, f 3.7.
The photo at the bottom is an underexposure. As you might have guessed, this is due to inadequate light falling on the image sensor. The camera sensor is unable to capture the details and hence the image looks like it was captured at dusk under fading light. Again, the details are lost in the dark tones and colours are very dull. This is at a very small aperture size, f 8.
| Exposure is a term that comes from the days of film photography. The amount of light to which the film is exposed to would determine how good the photograph is. This amount of light is controlled by the size of the aperture and how long the film is exposed [shutter speed]. Getting a correct exposure manually is the holy grail of photography. |
So in conclusion, the ability to get good detail and correct colours depends on the aperture being open at the right size for the existing light available. While it is also important to consider for how long the image sensor is exposed [The shutter speed], the aperture size will determine the correct amount of light needed for the scene to be captured well.
What aperture settings to use when?
The main determinant of aperture size, just like the human eye’s iris, is incoming light. Depending upon the amount of light in the scene, either the camera or you will have to adjust the aperture size. If the lighting is bright, the aperture should be small. If the lighting is low, use a bigger aperture.
A list of typical subjects being captured and the typical aperture size is given below:
| f-stop | Used in situation when |
| f 1.4 | Dark night landscape |
| f 2 | Moon lit night landscape, stars |
| f 2.8 | Night photos |
| f 4 | For most situations in artificial light, like a bulb lit room |
| f 5.6 | For most situations |
| f 8 | For most situations with bright light, like a spot-lit performer or an outdoor shot on a bright sunny day |
| f 11 | Sun lit objects other than snow like light coloured walls |
| f 16 | Snow landscape on a bright sunny day, well lit white objects |
| f 22 | Bright light, Sun lit snow |
If your camera allows you to adjust aperture settings, it is important you learn to do this manually. This would not only give you more control on the photograph, but will also allow you to get more creative with the photographs.
A note to point and shoot camera owners: If your camera does not allow you to change aperture settings, do not feel bad. This essentially allows you to concentrate on composing good pictures, while ‘outsourcing’ the technical work to the camera. Your camera will have a number of SCENE modes which essentially are presets of aperture and shutter speed. So in a way, when you use each scene mode in the appropriate situation, you are effectively adjusting your aperture and shutter speed, with a little help from the camera :)
Another very important aspect of photography that is dependent on the aperture is Depth of Field [DoF], but that is the subject of another post.
Until then, do leave your comments and suggestions. I’ll also be happy to answer any questions that you might have.
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