This series will be in parts. The overall goal will be to show you how to use your camera in manual mode to get the most control out of your camera. This is Part 1.
Understanding ISO in Digital SLR Photography:
ISO, shutter speed and aperture determine the exposure of a photo. This photo tip will eventually lead up to using your camera in full manual mode, so it is essential that you understand how all 3 apply to your photo.
What Is ISO?
The ISO (international Standards Organization) determines the sensitivity of the sensor in your camera, which affects the exposure of your photos. The ISO scale typically starts at 100, and continues to double from this point to the boundary of your camera’s capabilities: 100, 200, 400, 800, 1600… The starting and ending points of this range and how well the camera handles the ISO depends solely on the camera that you’re using. Many of today's modern cameras will have more than the points I've mentioned here.
How Does ISO Affect Exposure?
The ISO determines how well exposed a photo will be by changing the sensitivity.
---ISO is the setting that sets the image sensor’s sensitivity to light and thus the amount of light needed for a “good” exposure.
---The lower the ISO, the less sensitive is the image sensor to light entering through the lens thus requiring MORE light to enter the camera in order to achieve a “good” exposure.
---The higher the ISO, the more sensitive is the image sensor to light entering through the lens thus requiring LESS light to enter the camera in order to achieve a “good” exposure.
What ISO And When?
ISO 100-200: This will give you the most detail and best quality. Best for shooting in daylight. Shooting at a higher ISO in bright conditions would be unnecessary.
ISO 200-400: For slightly darker conditions, such as in the shade or indoors where it is brightly lit.
ISO 400-800: A good range to use when shooting indoors with a flash. This will produce a detailed background and more even exposure.
ISO 800-1600: A good range to use for indoor events where lighting is difficult and flash may not be allowed.
ISO 1600-3200: Use this again for indoor events, concerts and extreme low light conditions (unless using a tripod).
So...In plain English what does all this mean? Well, when I'm out shooting during the daylight hours, I usually shoot at ISO 100 or 200. As it gets closer to nightime or indoors, I may go as high as 800 or 1200 or higher. Depending on your camera and how well the sensor handles light, a higher ISO may cause "noise" in your photo. Noise being more grain in the photo.
In most cases, the lower the ISO, the better quality the photo: Lower number = Lover sensitivity = Finer quality photos
ISO is a key step in using your camera in manual mode (which is where this series of tips is headed).
I found this cheat sheet on the web. It explains all the facets I will try to explain in this series (Not my image and I couldn't find anyone to credit for it):
Don't forget to follow Part 2: Understanding SHUTTER SPEED
Feel free to comment and ask questions. I am giving this information which I hope you will find useful. This is not the end-all of photography information and I am not going into any real technical detail for advanced photographers. I'm trying to present this in a "plain-English" format for the beginner that wants to understand and improve their photographic skills. I am not a teacher. I am just trying to help. The steps here are how I learned and what opened the door to the world of photography for me. The more you know how your camera works, the better photographer you will become.
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