ISO Sensitivity / Noise levels (contd.)
In-camera High ISO noise reduction
The Ricoh GXR features three noise reduction settings - off, weak and strong. The default setting is off. High ISO Noise Reduction settings can be changed in the shooting menu. By default noise reduction kicks in from ISO 800 but you change the threshold. The difference between all three settings is very subtle but luminance and chroma noise are roughly tackled with the same intensity. At very high ISOs the strong settings smears a little more detail but all in all the difference is so marginal that you could almost question the point of offering different NR options.
|Noise Filter Settings compared|
Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of luminosity on the vertical axis.
High ISO Noise Reduction Crops
|ACR RAW NR OFF||JPEG NR Off||JPEG NR Weak||JPEG NR Strong|
Noise reduction and fine detail
The biggest issue with noise reduction - especially luminance noise reduction - is that in the process of blurring away the noise it can also have a very destructive effect on the detail in an image, particularly the fine, low contrast detail you might find in hair, fur or grass. To better judge the effect on fine detail lost due to noise reduction we have shot our studio scene and produced crops from the feathers in the image.
|To check the effect of noise and noise reduction on low contrast detail we shoot our studio scene framed as shown here, with the new added feature of feathers. The very fine detail in the feathers will help to better judge the effect of noise reduction on fine detail.|
Raw vs in- camera JPEG noise reduction low contrast detail comparison
As you can see from the crops below, at the 'Off' setting the output is very similar to the RAW images. At ISO 800, when the noise reduction kicks in, you have to look closely to see a difference between the 'Weak' and 'Off' settings, only the 'Strong' image is noticeably cleaner but also already loosing some detail. As you go higher up the ISO range the differences become a little more visible but always remain quite subtle.
|ACR RAW NR OFF||JPEG NR-Off||JPEG NR-Weak||JPEG NR-Strong|