Learn aboutMax light sensitivity - ISO

Short Description

Sensor light sensitivity refers to a cameras maximum ISO setting. ISO is an international standard that was used to denote the sensitivity of film. Digital cameras retain this notion of light sensitivity. Every time the ISO number is doubled, say from ISO 100 to ISO 200 the amount of time you need to expose the photo is halved. Say for instance your camera needed 1 second to properly expose a photo of your cat , even if you setup a tripod so that your camera was perfectly still your cat might not be. What you need is have proper exposure in less time to avoid blur. You need more sensitivity - at ISO 3200 you would only need an exposure of 1/32 of a second, enough to get a photo with minimal blur if you have a stead hand. Unfortunately the higher the ISO level the less time the sensor has to detect the true colors of the image you're capturing (less exposure time) - because of the reduced exposure time noise is introduced to the photo - the noise is the direct result of the lack of light on the sensor. Less light makes it hard to determine the true value of each pixel. That's the compromise with higher ISOs - more noise and lower quality. At higher ISOs many cameras have aggressive noise reduction algorithms that essentially blur the photo, but many cameras have strong performance up to reasonably high ISO levels, the low light performance rating indicates how high you can take the ISO and expect good quality and is available for most DSLRs

Best Low Light Pro DSLRs

The following Pro SLRs have great low light performance.

Best Low Light Entry Level DSLRs

The following entry level SLRs have great low light performance.

Why Shorter Exposure Times are Important

Say for instance you wanted to take photos indoors without using a flash, perhaps of a birthday party, you would want your film to be more sensitive to light so that you didn't need to expose as the photo as long. Longer exposures are problematic because if your subject is moving or your hands aren't completely steady it can result in a blurry image - the blur is even more amplified if you're zoomed in on your subject - for instance at a sporting event held indoors - one small move of your hand becomes a giant movement against your subject who could be hundreds of feet away. Blur can turn your 10MP camera into a .5MP camera in short order. Short exposure times are important to capturing the most detail via a completely steady exposure so each pixels is capturing unique detail.

ISO Examples

The following two shots were taken of the same subject at the same time with different ISO settings on a D90. While the ISO 200 exhibits no noise the ISO 6400 is showing tremendous noise both in color and luminosity. At 6400 ISO your get 4 stops of advantage, meaning you need only expose the photo for 1/16 the time, but the consequences are obvious. At 6400 ISO the usable resolution is probably about 25% of what you're getting at ISO 200 - about 3MP on a D90. But you can do a lot with 3 megapixels so its still quite useful to have.

High ISO Digital Cameras

The following digicam digital cameras have high maximum ISO and larger digicam style sensors.

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