Aha! Just as I thought.

People out there want to learn more about taking better control over their digicams, but the damn guides all over the place just fill your head with unnecessary and confusing jargon. Anyone can tell you how to talk the talk, but my purpose here is to show you how to walk the walk. So before I jump into mindless faffing modes, let's get to the point.

If you missed the last feature I did on this series, then you should probably check that out first. There I have explained the basics about what shutter speed and aperture size is and how you can make it work for you. If you've gotten the hang of these concepts (and you will with a little trial and error), its time to move on to a few other secondary, but essential concepts that will help you take pictures that will woo the hearts of women and make you a champion among men... or at least make your photos look better.

ISO Sensitivity
The Idea:
Yep, it's the same ISO as International Standards Organization. The thing is they had created a standard for the sensitivity level of camera films in relation to the amount of exposure time they need to form a picture. The same concept has been carried forward to the digital sensors in your cameras now.

Besides the FYI above, what to need to know is that the high ISO sensitivity levels are better suited for dark environments and lower ISO levels are better suited for well lit areas.

The thing is that when you use a lower ISO level, the camera's sensor needs a decent amount of exposure (depending on the lighting conditions) in order to form an image on it. If you use low sensitivity like ISO 80 in broad daylight, even a high shutter speed with give the sensor enough exposure to form an image on it, which makes it a great option for brightly lit areas. But if you use that same sensitivity level in a dark area, the camera will require a much lower shutter speed to form an image, which would be hard for a regular user unless he's using a tripod and shooting a still subject.

This is why in dark areas you can go to ISO levels like 200 to 400 depending on how dark the lighting is, which can form an image at even higher shutter speeds, reducing the chances of a blurry image.

So you may ask, why not shoot at a high ISO level and high shutter speed all the time, and eliminate any chance of camera blur in any condition. But then I'd probably give you a tip about how life is not fair and then give you the actual reason why it's a bad idea to do that, which is -- As you increase the ISO sensitivity, the sharpness and the overall quality of the image goes down. So while an image shot at ISO 80 will look sharp and have deep colors, an image shot at ISO 800 will probably have some digital noise, watercolor-like uneven lines and bland colors.

It all depends on the camera's sensor, how well it handles higher sensitivity levels. So while an SLR camera may give you sharp images even at ISO 800, a consumer camera may plague the image with digital grain at that setting.