ISO Sensitivity / Noise levels

Standard Test Scene

ISO equivalence on a digital camera is the ability to increase the sensitivity of the sensor to enable faster shutter speeds and/or better performance in low light. The way this works in a digital camera is by "turning up the volume" (gain) on the CCD's signal amplifiers. Nothing is without its price however and doing so also typically increases visible noise (random speckles visible all over the image).

Just like the F700 the S5000 produced a very odd plot on our standard noise measurement test. After examining higher ISO images in detail we discovered that this is because the camera drops its sharpening considerably to keep noise down. Thus instead of posting crops of grey patches I thought it more appropriate to provide examples of what effect this has on image detail.

As you can see from the 100% crops below the S5000's noise reduction system is either softening the images or works in conjunction with the rest of the image processing system to turn down sharpening.

ISO 200, 1/27 sec, F5.6
ISO 400, 1/56 sec, F5.6
ISO 800, 1/110 sec, F5.6 (Forced 1MP: 1280 x 960)