The three pillars of photography was mentioned in one of my very early posts which covered the different shooting modes of the camera. If you have explored the camera beyond the automatic mode, you must have definitely heard of the terms aperture, shutter speed and ISO . They are nothing but the elements whose values when rightly balanced , helps achieve a correctly exposed photograph.
When a photograph is too bright, we say it is overexposed and if it is too dark it is said to be underexposed. If we rightly balance the three elements mentioned above ,we can get a great result. Manual mode of the camera can be used to set all the three elements as desired.
- Aperture is a tiny hole in the lens formed by small set of blades that lets or allows the light into the sensor of the camera.Bigger or wider the hole, more light is let in and smaller the hole, less light is let in . So f /2 (wide aperture) will let in more light than f/16 (small aperture). Every f-stop change will either increase or decrease light by double.
- For portraits, wider apertures like f/1.4, f/2.0 etc will work perfectly. They uses a shallow depth of field as well ,helps the subject to be in focus and blurs the background ,also called bokeh.
- For landscape shots, where you want the entire picture in frame to be in focus, shift the f-stops to small apertures like f/8, f/16, f/22 etc which have deep depth of field.
- Most lens are sharpest at f/5.6 or f/8 but photographers are ready to compromise some sharpness for subject isolation and bokeh.
SHUTTER SPEED :
- Shutter speed is how fast the camera's shutter closes and opens, to let and allow light into the sensor of the camera .It is measured in fractions of seconds when under a second.
- Slower the shutter speed, say for example 1/30 s , more light is let into the camera which results in brighter images. However blurring is a possibility at slow speeds . It is recommended to use a tripod for shutter speed lower than 1/60 s
- Faster shutter speeds like 1/1000 s allows less light . Faster shutter speed can be used to capture sports events, fast moving objects or even avoid camera shakes.It is used to obtain sharp images, but can also result in dark images due to less light.
- ISO is the measure of camera's sensitivity to light and this value helps one to work with less light. It can be used to brighten your photos when you can not use a longer shutter speed or a wider aperture.
- The lower the value, it is less sensitive to light and higher the value it is more sensitive to light .
- It is best to keep ISO to a low value like 100 and then increase as needed. Higher ISO values can make the picture noisy and look grainy whereas the lower ISO values results in a smooth and fine image.
The illustration above gives a better clarity.As the f-stop values of the aperture changes to lower f -values from f/5.6, f/4, f/2.8 etc moving left , notice that the brightness increases and so does the shallow depth of field . In other words, the subject is in focus with increased blurring of the background (bokeh) . For higher f-stops values f/16, f/22 etc , it is the other way round brightness is reduced , but the whole picture is in focus and with greater depth of field. Similarly for shutter speed, as the speed decreases to say ⅛ s etc, the image is bright, but gets blurry. This can be used to capture a waterfall with a misty and dreamy effect. For faster shutter speeds, as the speed increases say to 1/1000 s the image gets darker, but image is sharp .This is especially used to capture subjects in motion like a bird flying , dance or sports event etc.For ISO , the higher the value more brighter the image. The downside is it can get grainy . Lower ISO values result in fine images .
Where to set the exposure values? Set to the manual mode "M" from the mode dial of the camera. You will see the LCD display screen similar to the one below from where the values can be set.
The picture of the exposure triangle gives a good overall idea on how to manipulate the three values to get a properly exposed photo. If you were for example, capturing a close-up shot of a flower with exposure values f-2, 1/1000 s and ISO 100 , experiment next by changing the f-stop to f-4 , but reduce the shutter speed to 1/500 and ISO 100 . Since higher f-values results in less brighter images , it makes sense to decrease the shutter speed to 1/500 s else you would get an image that is too bright or an overly exposed image .Keep practicing using trial and error by setting your camera in manual mode .It won't be very long you are intuitively turning dials like a professional . Happy clicking !
Disclaimer: I am not a photography tutor or professional .This is only an effort to share the lessons and tips I learnt , refresh the concepts I learnt and compile my experiences using the digital camera .