I'm taking shots in a pretty dark place and expect some noise with my inexpensive Olympus E-M10.II and kit lens at ISO 3200. When I process pics in LR, often as they are loading, and the image has appeared, and the loading spinner is going, the shot looks pretty good in the Develop window. When the loading spinner goes away, suddenly there is a bunch of noise that wasn't there before. Below are two pics to illustrate. The first is what I see when the loading spinner is about to appear (it's not shown in this picture, but it's a half-second from appearing.) The skin is smooth and the top of the cello is clear. The second shot is what I see when it's finished loading. Noise galore. Check the skin and the top of the cello. What's LR doing that it seems to have a good "loading" shot but when it's done there's noise? I have dozens of pictures from a string concert last night that have exhibited this issue when I'm loading them. (I have an older laptop, so loading a bit of time for me.)
Thanks for helping.
This is normal for typical high ISO shots, the noise reduction set by default in Lightroom Classic is very conservative. Usually far more conservative than what cameras do to the jpeg preview rendering (what you see on the camera for raw files and as the initial preview). At first Lightroom shows you the jpeg preview from the raw file before it shows the actual raw data. You simply need to optimize the noise reduction and sharpening for these images and sync those over all files shot similarly. Make sure you only touch the noise reduction and sharpening sliders in the 1:1 view as all other views (except the even higher zooms) are inaccurate for the detail (noise reduction and sharpening) settings.
Thank you for your answer - it makes sense given what I'm seeing, and it has also prompted me to view the in-camera JPGs, which I have usually not bothered with. The camera does a remarkable job of noise reduction on its own.