Lightroom Classic: Smart preview problem in Sony Alpha 9 Files
I am facing an issue with lightroom smart previews, only on Sony Alpha 9 images.
I import the Alpha 9 RAW files, build smart previews and disconnect the RAW's (to increase lightroom speed), and edit the images. Once I am done editing, I export the images in Smart Preview resolution. Everything is fine and there is no issue till this.
But after a while, I connect the catalog with the RAWs to export in Original Resolution. When I do this, there is a considerable difference in the exposure between the smart preview export and the RAW export. The exposure difference is not present in all the images but only a few. The export setting for both is the same and I have not changed any other settings (exposure, tone curve, etc.,). I have attached my export setting down below. I am using a Windows system and I have attached the specs down below as well.
I have attached a video here to explain this better. In the last few minutes of the video, I have shown the differences between Original RAW export and Smart Previews export. In the 1st image, the RAW export appears brighter than the smart preview export. But in the 2nd image, the smart preview export appears brighter than the RAW export.
There is no consistent pattern on how the exposure is changing, sometimes RAW export appears brighter, but sometimes it appears darker too. But clearly, there is a difference between the two exports.
There is one other user who reported the exact same issue, but no clear solution was provided to that. You can go through the thread here:
Note: This is an issue present only in Sony Alpha 9 cameras and it is not consistently seen in all the images as well. Around 5-10% of the images have this issue.
Reproducing the problem: Since this issue is not present in all the images, I am attaching a few RAW images which will help in reproducing this. You can download it here.
Step 1: Download the RAW files which I have shared above.
Step 2: Import it into Lightroom and build smart previews
Step 3: Disconnect the RAWs and edit the images. In order to see the exposure difference clearly, increase exposure difference well, and burn the background.
Step 4: Export the edited images without connecting it with the RAW files. From what I have understood, this issue does not seem to occur in any particular export settings. So any export setting is fine.
Steps 5: Once you finish this, connect it with RAW files and export it again.
Ideally, there should be no difference between the Smart preview export and the RAW export. But in this case, the RAW export will appear different than the smart previews export. You will notice this, especially in image no: KB100732. I have uploaded the 2 different exports of this image in this link.
I tried converting the RAW files into DNGs (to check if the RAW files are causing this) and did the same process again. But the issue is still present. I have also tried this in the older lightroom version (8.21), but no luck there as well. I have tried this on multiple systems (both Windows and MAC). The issue persists.
Here is my system spec: