Shutter Speed and ISO Speed

(Base Knowledge IV)

(II.) Shutter Speed

Longer shutter speed, more lighter (over-exposure) image will be produced. And to solve this problem, we can set smaller (relative) F-number. Shutter speed has same function with Aperture (F-number) as controlling quantity of the light that pass the lens. So, longer shutter speed is equivalent with smaller aperture value –for producing a normal exposure. Which the combination between two of them can create a different effect, even in the same exposure.

Generally, range value of shutter speed on most digital camera is 1/16000 s – 30 s on normal condition, and unlimited when taking a BULB technique.

Below, it’s Simple technique to create an effect with shutter speed..

1. Shoot a moving subject at a moment in time. Use a faster shutter speed to crisply shoot an instant of the movement.

2. Trace the movement to express the dynamism and flow. Use a slower shutter speed to shoot trailing image of the moving subject.

(III.) ISO

ISO (ASA): stands for International Standards Organisation. The initials are used for digital camera’s censor which rates light sensitivity. A censor with an ISO number 100 is twice as light sensitive as a censor with an ISO of 50. The faster the digital camera’s censor, the more sensitive it is to light.

Sensitivity to light is expressed by the ISO number. The larger the number, the higher the sensitivity. Which higher sensitivity can produce image more colourfull, more brightness. But in some case like shooting in low-light, when combination between shutter speed and aperture are less-accomodations –is foced to increase ISO value, it can appear some noise in a picture. Why?? Noise is colourfull spots that appear because of cencor of the camera is forced to more senstive to the light. Or it will caught more light from the source imperfectly, cause the source is less-light.

So, keep lower the ISO number when shooting in a low light, especially in the night. Of course it can decrease shutter speed (take a long time when shooting).
Set higher ISO number when its in daylight or in a bright-light source, it will bring you more colourfull light in your picture. . . keep the number depending on your mood.