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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 can change the threshold. Like on the A12 module on the S10 24-72mm 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' and 'weak' settings blur a little more detail than the 'off' setting but the difference is marginal. Even at the 'off' setting there is actually still quite heavy noise reduction being applied.

  Noise Filter Settings compared
Off
Weak
Strong

 

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 Off Weak Strong
ISO 100
ISO 200
ISO 400
ISO 800
ISO 1600
ISO 3200

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, like many cameras even at the 'Off' setting the S10 24-72mm still applies some noise reduction. The RAW shots show at all ISO settings more detail. Noise reduction 'officially' kicks in at ISo 800 but again the difference between the noise reduction settings is pretty small. All of them are relatively strong. If you shoot in RAW+JPEG format you can apply your own noise reduction settings in post processing.

Please note that the RAW files in this comparison have been processed in Graphic COnverter 6.7 (DCRaw) to eliminate all noise reduction. As we've seen on the previous page Adobe ACR still applies some noise reduction to the RAW files even when NR is disabled.

  ACR RAW NR Off JPEG NR-Off JPEG NR-Weak JPEG NR-Strong
ISO 100
ISO 200
ISO 400
ISO 800
ISO 1600
ISO 3200
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