Monday, 25 August 2014

Quick Notes on Olympus RAW and Lens Profiles in Lightroom

Here's a verbatim copy of a post to a FB group when we were discussing Olympus Lens Profiles and Lightroom. I'll update this when I get feedback, corrections and so on.

The Adobe Lens Profile issue is potentially confusing. Let me note the points and hopefully people can add / discuss.

1. ORF - the Olympus RAW or any camera model raw needs to be understood by the raw processing program. New camera models are released every few months, the third party companies like Adobe have to scramble to get their programs updated. Sometimes, the sensor is the same but the EXIF signature is different e.g. my E-PM2 file is similar to the OMD E-M5 but some old programs refuse to load the E-PM2 raw. If I use an EXIF editor and change the camera name, presto, the old program reads the file.

2. Adobe has a habit of deciding that a certain version of LR or ACR will no longer be supported by them - they make money by selling new versions - they don't get income by supporting their old programs for new cameras. Adobe is not the only company that does this. The Adobe blog will have announcements on which version of LR or PS a certain new model starts getting supported.

3. The Lens profile is not related to the sensor data of raw - it describes vignetting, fringing, curvilinear distortion. Since last year, there have been additional lens info being stored - e.g. the lens bokeh / out of focus info - Panasonic uses this for super fast focussing in the GH4. Olympus uses it for when rendering the JPEG in the camera or Olympus viewer. If the program can read the raw, it can produce an image on screen and for JPEG, it just doesn't automatically correct for the lens behaviour.

4. Olympus from Four Thirds lenses era (1990s) stores this data in lens firmware. Panasonic does similar. That PhotoHelpdesk article claims that Adobe LR reads that and uses MFT lens data from the raw file. I don't know the truth of that claim.

5. For other brands of camera and lenses, or for manual focus lenses, Adobe or users can run the Adobe Lens Profile Creator program and produce separate lens profile files - many of the other brands lenses are automatically installed with LR - hence you can see them in the screenshot of the menu above. If you download the Lens Profile Creator software, you can also run a menu item that grabs Olympus Four Thirds DSLR lens profile files from Adobe and installs them into the LR subfolder.

6. In LR 5.6, I have tried "Enable default lens correction" on a raw but I don't see the image wriggle if the lens name is not identified. If the lens name is identified, I see the image wriggle once - I think this means the lens correction has taken action.

7. This lens correction data is typically in raw metadata because we assume that the file is clean from the camera. It is not stored in JPEG because the JPEG is normally "baked" or "cooked" already. Certainly software can correct the JPEG but the industry hasn't catered for that aspect.

8. If you shoot SOOC JPEG in an Olympus body, it is corrected for vignetting and curvilinear distortion. The Olympus RAW is not corrected but it contains the data. If you shoot SOOC JPEG of a Panasonic lens on a Panasonic body, you also get correction for fringing (CA).

No comments: