In the last post we came to know about What is right exposure and the factors affecting the exposure of a picture. To register a perfect tone image on your digital camera sensor, one must allow the correct amount of light to reach the digital sensor. The three factors that control the path of light are sensor sensitivity (ISO), shutter speed(SS), and aperture(f-stop).
When the film photography was dominant, exposure was an really important subject. The digital era has brought us light-years forward because we can now see the result instantly. Just as with film cameras, the DSLR takes into account the brightness of the frame, the contrast, the color of the picture and the area in focused. When automatic exposure is set, the camera calculates all the settings accordingly and much more instantly.
You can now review your pictures immediately after exposing, on the LCD screen on the back of your digital camera. If you are a beginner to photography, there are many other different aspects that have to be considered before you take each picture. How do I compose the picture? Is it in focus or not? What should be the background? Until all these elements start to become second nature, it’s good to keep your camera on auto-exposure. This will give you one less thing to worry about while you concentrate on all the others parameters. Then gradually, as you become more technically strong and have learned to hold the camera the right way, you’ll start to adjusting the small adjustments that are possible on your camera to get a perfect exposure as per your learning and experience.
On most of the DSLRs and high-end compact digital cameras, you have the option of setting the exposure manually(M-mode). This is time where we begin to play with the camera’s settings to get perfect exposure. Moreover we now start overexposing and underexposing the photograph as per our need.
- Camera Sensor Sensitivity(ISO)
In Film photography you need to change films if you want to change the ISO. Eg. If you are shooting at ISO100 film and suddenly the weather changed now you need ISO400 to get your desired image, So you need to change the other film of ISO400.
On the other hand in Digital photography, DSLR allows you to shoot a group of pictures, or even a single picture, at one ISO setting, then change the ISO setting on the same memory card and keep shooting. You can change the ISO as many times as you need.
- Shutter speeds(SS)
Here are some basics about shutter speeds to begin with:
• If the light is really bad, try not to go below 1/60 second. If you must, hold your camera very still and don’t expect to freeze any action.
• For everyday pictures such as portraits and views, use speeds of 1/60 second to 1/250 second.
• To stop a racing car, or someone riding a bicycle, start with 1/1000 second.
NOTE: To avoid the camera shake, your shutter speed should not be less than the focal length of the lens you are shooting with.
- Aperture (f-stop)
Here are some basics about Aperture/f-stops to begin with:
• As a general rule, f/5.6 gives a little bit of depth of field, provided the lens focal length isn’t too long, and is still wide enough to enable high shutter speeds.
• If it gets really dark, don’t be afraid to open your aperture to its maximum available aperture, for example, f/1.2 or f/1.8.
• If you need loads of depth of field, or you want a slow shutter speed, stop down to f/11 (when using a short lens) or f/16.
If your picture looks a little bit lighter or darker than it should, take another parameter to adjust the exposure. You can make your image lighter by increasing your exposure, or darker by decreasing the same. NOTE: f/8 can be used as a universal aperture perfect for any genre of photography.
Note: Your most of the lens usually gives the best sharpness at one stop down to the widest aperture available at your lens. eg. Lens with f/1.8 will give its best sharpness at f/2.8 not at f/1.8. anyone can experiment this and visualize the difference.