Luminance introduced in RAW processing

[fishcad]

Very often when I adjust an image in the RAW processor a lot of noise is introduced.  If I adjust the luminance to remove the noise it also reduces the sharpness in fine features.  Adjusting the sharpness just reintroduces the noise.  What happens in RAW processing that introduces that noise?

[MichelBParis]

The noise is by nature in the raw data. Raw processing does not introduce noise, it reveals it because it is always partly hidden by the processing to produce visible (jpeg) images on your camera display or the jpegs when you shoot raw plus jpeg.

All photo editors (raw or pixel) have to offer a compromise between noise and sharpness.

The 'detail' tab in the ACR dialog has superior tools to find the best settings. The 'luminance', in fact the 'luminance noise' control is the main setting. Very important, you should set your zoom level to 100% to see the real effect.

The other sliders, particularly the detail one, counterbalance the softening effect and let you adjust the sharpening for the luminance denoising you have chosen.

There are probably good tutorials on how to optimize denoising in the ACR dialog with the different sliders; I'll try to find one.

https://helpx.adobe.com/camera-raw/using/sharpening-noise-reduction-camera-raw.html

[fishcad]

Thanks for the explanation.  Three more questions:

Is ACR the same for Photoshop Elements as in Photoshop? 

Do you have any idea what the Detail settings would be in ACR to get the results from the camera processing for jpg? 

Is there any difference in the way one should adjust an image if it is a *.RW2 from a Lumix camera or a *.CR2 from a Canon?

[MichelBParis]

- Photoshop Elements ACR plugin has a reduced number of features compared to Photoshop.

- Only the raw converters offered by each camera manufacturer can exactly reproduce the jpeg settings of the camera. Adobe offers very near renderings in the settings of the ACR dialog, depending on your camera model

- The editing workflow is exactly the same for all supported raw formats and also for jpegs opened 'in ACR' from the editor file menu.