P: Allow ability to adjust Denoise slider value prior to Denoise running (LrC)

Its also a huge waste of electric energy and computing power to effectively use AI Denoise 2x on one image just to get the Denoise right. This is a bug, and it needs to be fixed

This is an obvious bug. I preferred the way it worked before, even though it was a estimated simulation, I could see what the setting was going to do to the detail in photo while it removed the noise. Once I get a feel for this, with each camera in each ISO situation, I can make proper presets but this is a lot of unnecessary work. Please fix this bug. 

Ive used Denoise for long enough to know almost every camera sensor in my catalog and what level of Denoise each needs. The feature was scary/good, and I have to believe that Adobe didnt intentionally put this in their application. 

But why are we not able to adjust that level slider? I dont want 50 for any of my cameras. This has to be a bug in the sauce. I hope they are working to change this error. 

@ExUSA: "In both Lightroom and ACR, the Denoise amount cannot be adjusted before applying it."

Two methods:

1. In Develop while editing a photo that has Denoise - 40 applied, define a preset "Denoise 40" with just Detail > Denoise, Raw Details, Super Resolution checked.  Then in Library, select all the desired photos and do Quick Develop > Saved Preset > Denoise 40.  This method is good for people who generally use a given amount based on their camera and their shoots.

2. In Develop with the current photo, apply Denoise and then change the slider to 40. In the filmstrip, select all the photos. Click the Sync button and select just Detail > Denoise. This method is good for a shoot where you're unsure of the amount, so you experiment with one photo and then apply it to all the rest.

You can also use Auto Sync for this (as mentioned previously), though Auto Sync is dangerous -- too many posts here over the years of people forgetting to turn it off and not noticing until it was too late.

@ExUSA 

Why do you need to set the Denoise Amount before denoising?

How do you know what Amount you want? Experience possibly.

The non-destructive Denoise just does things in reverse to the old DNG method.

First let's consider Denoising just one photo.

With the former DNG method, you had a preview window set to a fixed zoom that many found was excessively high. You could set the Amount based on what you see in the preview prior to committing to Denoise and creating a DNG with a baked-in Amount of Denoise. If you want to change the Amount sometime in the future, Denoise had to be run again, creating another DNG. The Denoised DNG doesn't inform you what Amount was applied to it, so in the future, you will not know what Amount was used to create it unless you noted it somewhere in the metadata.

The new non-destructive method runs Denoise when the checkbox is checked, applying the default Amount of 50. You can now alter the Amount slider to whatever setting that you like, whenever you like. You can zoom your photo to whatever level you choose to access that change made by the Amount slider in real time. You can always come back to the photo and know what Amount was applied to it.

I see no problems here when using non-destructive Denoise on one photo; in fact, I see this as a very positive change.

Now let's look at applying non-destructive Denoise to a selection of photos with Auto-Sync enabled.

Many users who are complaining here don't realise that they must enable Auto-Sync first, which I find quite astonishing considering that many of those users are professional photographers with years of experience using LrC.

With Auto-Sync enabled:

1. Check the Denoise checkbox, which is done to all the photos in the selection
2. Denoise is applied to the active photo in the selection
3. At this point, you don't see it, but the remaining photos in the selection are marked as needing an AI Update
4. AI Update is invoked on the remaining photos in the selection; one less than the number selected since the active photo has already been Denoised

You can Stop the AI Update processing immediately if you want to; you can then see by activating one of the photos in the selection that AI Update is needed (yellow AI Update Status icon). Assuming that you still have the selection, Shift+Click the AI Update Status icon will start the process again; any photos in the selection that did get Denoised will be skipped over almost instantly.

The big problem and I mean BIG, is that changing the Denoise Amount slider for a selection of photos initiates an AI Update process again for all the photos. This is a huge bug and is totally unnecessary and this is what really needs to be fixed now!

The other major complaint, and justifiably so, is that Denoising a large selection of photos is a slow process which is not being done in the background like before. This holds up users from continuing work on other activities in LrC while Denoise is being applied. For professional photographers Denoising very large selections, this costs them time and money. It is hoped that Adobe finds a workable solution to this seriously negative aspect of non-destructive Denoise.

The  denoise option in the  latest version of Lightroom (LRC) does not give you the option to "preview". It starts the denoise immediately after you click the denoise button. No preview is given. Therefore you don't have the option to increase the or decrease the amount of denoise and view it on the screen before you actually denoise. Why was this taken away?  It makes the denoise option much less user friendly and is a few steps backwards. Will this be put back in (the preview screen) in the next install or in this one?

Bonjour, depuis la mise à jour LR 14.4 je n'ai plus le choix de mon niveau de réduction du bruit par défaut à 50 , curseur grisé inaccessible.  Dès que je coche une case le process commence sans possiblité de réglage

There have been multiple versions/UIs. Lightroom Classic has had two versions, and Camera RAW has had three (previous with DNG, previous technology Preview, current release.) Each has looked and worked a bit differently than the others.

Post a screenshot of what you do see in Detail. I get the distinct feeling that there is nothing wrong, but that you simply did not read the "What's New" info on how AI Denoise has been changed from a version that created a DNG to the non-destructive setting it is now.