When using the Process with Topaz Photo AI LR plugin (from file/plugin extras) Topaz will take the original file and create a DNG file from Canon Raw CR3. The new DNG loses Lens profile settings for the aperture.
This is important because Lightroom needs the aperture setting to apply lens correction. In this particular case I am using a fisheye lens and lens correction is drastically different for this kind of lens, which flattens out the image to make it ultra wide. This is very important. Thus you lose the ability to apply Lightroom’s profile correction on lenses after importing it back in.
If you compare the exif data from the original file the lens profile will typically be something like the following:
Lens: 15mm f/2.8 #0000000000
Lens: 15mm #0000000000
I will also note that Topaz also strips out the firmware version of the camera from the exif data.
Attempted workarounds that don’t work:
Apply lens correction in LR before import. Doesn’t work because Topaz can’t use Lightroom’s develop module settings (this is an issue in and of itself, forcing people to use topaz ahead of editing as opposed to after which can put noise back into an image)
Apply lens correction on import to Topaz Photo AI. - Not sure of the algorithm here but it simply doesn’t see to do much. Perhaps Topaz and LR use different algorithms but for me this has never proven to do much of anything and in the case of the fisheye it doesn’t work at all.
Convert to TIFF with LR settings and then use Topaz Photo AI. This works with obvious limitations and is not a workaround so much as it is a compromise.
Normally I would attribute this stripping to having limitations on the perceived length of the exif fields and truncation on Topaz’s part but that doesn’t explain losing the aperture setting. Most likely this field is a tuple and Topaz simply misses putting it back in.
Steps to reproduce issue:
- Step 1 - Import image from Lightroom using the Plugin Extras option on the file
- Step 2 - Allow Topaz to enhance the image automatically and save
- Step 3 - Inspect the exif data comparing the two files. I use an external program to look at the exif data and you can clearly see the missing data.
Topaz Photo AI [v1.5.1] on [Mac]