While Lensfun's lens database is pretty comprehensive, it does not contain all lenses. Moreover, only for distortion correction, the coverage is at almost 100%. Most datasets lack vignetting data, and many lack TCA data. Therefore, it may be helpful for you that Lensfun is able to use so-called LCP files. LCP files contain lens correction information – just like Lensfun's database does. Usually, one LCP file contains data of exactly one lens. The LCP file format is defined by Adobe (see the specification) and used in their Lightroom and Photoshop products. Everyone can create LCP profiles using Adobe's Lens Profile Creator. Moreover, a comprehensive library of LCP profiles is shipped with Adobe's DNG converter, but pay attention to the licence agreement associated with this software.

The RawTherapee community has created a page describing in detail how to get LCP profiles. Additionally, you may google for further sources of LCP profiles.

Once you have put the LCP files in a directory on your computer, you can easily import them into Lensfun by calling “lensfun‑convert‑lcp” in this directory. After that, the data is immediately available in your favourite Lensfun-using RAW converter. “lensfun‑convert‑lcp” merges the two data sources, so you get the best of both worlds. See the manpage of “lensfun‑convert‑lcp” and its output with the “‑h” option for further information.

Note however, that Adobe files tend to undercorrect distortion and vignetting. In particular, vignetting is corrected only partially. Moreover, since recent Adobe products do not correct TCA based on LCP files anymore, TCA coverage is bad for newer lenses. And last but not least, automatic lens detection is much more reliable with genuine Lensfun datasets. In Lensfun's official database, no profiles using “acm” models are accepted. Thus, instead of using LCP profiles, please consider uploading RAW images suitable for calibration. This way, you do not only benefit from increased quality, but you also help others with the same lens models by providing freely available data.

Thank you!