P: Make HDR work with AI denoised AE bracketing images

[mwfn]

Using LR classic Version 14.5.1 with Camera Raw 17.5 on a Windows System.
I recently acquired several images using autoexposure bracketing with the intention of creating HDR images later in Lightroom. I realized too late, that during the bracketing series my camera automatically adjusted the ISO value for each raw file. So now the raw files have different ISO and therefore different noise patterns.
I can use the HDR function on the RAWs but the result looks quite terrible with re. to noise and the HDR image cannot be denoised using the AI denoising tool.
So I then used the AI denoising filter and subsequently applied the HDR function in LR classic. This caused quite dramatic artefacts, it looks to me as if the denoising filter is discarded when HDR grabs the raw images:

It would be great if the HDR function would be made compatible with the denoising function.

[JohanElzenga]

HDR is merged from the original raw images, so indeed denoise of the brackets is ignored. However, I believe that the resulting HDR DNG image should be supported by AI Denoise. I can't check that right now as I'm typing this on my iPad, but I'm pretty sure this is a recent change. As an 'HDR' merged from ISO-brackets is not really HDR at all, the results of your particular example may indeed be poor, however.

[Karsten.G]

In the past, when denoised images were still DNGs, I ran some tests to compare a denoised HDR created from noisy individual images with an HDR created from denoised images, out of curiosity. In all cases, the latter produced better results. This is not surprising, given that denoising should be applied before editing. 

Since HDR Merge used to work with denoised images, I hope that Adobe will bring back this option and allow users to decide when to denoise.

[JohanElzenga]

What you could do is denoise the brackets, and then export them as 16 bits ProPhotoRGB TIFF or PSD files. Then import these into the catalog again and merge them to HDR. I know this is not exactly the same as merging denoised DNG files in the past, but the difference should be minimal.

[mhozza]

This is quite frustrating. You can indeed use ai denoise on the resulting image, but there will still be artifacts, as it seems to apply the same denoise level for all parts of image, including those coming from the noisier shots and that results in a weird patches of noise. 
Previously when I applied the ai denoise, it created separate denoised dng files. The denoise on the noisy image was still handled quite well - resulting noise was fairly similar across the images - and you could also finetune it individually.