Noise is not reduced when shooting using Multi-frame noise reduction feature.

Multi-frame noise reduction helps to reduce picture noise by building up exposure and allow larger ISO numbers to be selected than the normal maximum ISO sensitivity. The noise reduction is less effective if High ISO NR is set to OFF. Therefore, it is recommended to set High ISO NR to Normal or Low when shooting with a high ISO setting.

NOTE:  If model-specific information is needed to change the High ISO NR setting, refer to the instructions supplied with the product.