Low contrast detail & NR options
What the crops and graph on the previous page don't show is the effect of noise reduction on low contrast fine detail such as hair, fur or foliage. An inevitable side effect of noise removal is that this kind of detail is also blurred or smeared, resulting in a loss of 'texture'. The crops below show the effect of the FZ 18's highest and lowest levels of noise reduction on such texture (hair) as you move up the ISO range.
|ISO 100 NR - 2 (low)||ISO 100 Standard NR||ISO 100 NR + 2 (high)|
|ISO 200 NR - 2 (low)||ISO 200 Standard NR||ISO 200 NR + 2 (high)|
|ISO 400 NR - 2 (low)||ISO 400 Standard NR||ISO 400 NR + 2 (high)|
|ISO 800 NR - 2 (low)||ISO 800 Standard NR||ISO 800 NR + 2 (high)|
|ISO 1250 NR - 2 (low)||ISO 800 Standard NR||ISO 800 NR + 2 (high)|
|ISO 1600 NR - 2 (low)||ISO 800 Standard NR||ISO 800 NR + 2 (high)|
At all ISO settings there's very little difference between the lowest (-2) and standard noise reduction settings. However, the highest setting (+2) is producing even more of the classic smearing that robs shots of the fine low contrast detail needed to preserve the 'texture' of a scene, even at base ISO (100). From ISO 200 the +2 NR setting is having a serious destructive effect on the low contrast hair detail - Panasonic is blurring the chroma noise away, and this is the result. It's also obvious that the luminance noise is being attacked pretty hard too at ISO 400 and up.
The low and standard NR settings are a little better, preserving a touch more texture, though you can see noise in areas of flat color and in shadows using this setting. At the end of the day it's easier to remove noise (selectively if necessary) than to put back lost detail (which is, by definition, impossible) - so you may want to permanently turn the NR down to -1 or -2, particularly if you are using anything over ISO 200.
From ISO 400 upwards the differences between all three NR settings shown here become more and more marginal, the lowest (-2) NR setting looks a tiny bit sharper, but there's a lot of blurring in all sample shots. At the end of the day it is a matter of personal preference, some prefer sharper noisier pictures, others prefer all noise to be ironed out. At ISO 800 and above there's little point worrying about the NR setting anyway.