6-bit coding comes into its own.

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My earlier piece on 6-bit coding of Leica M-mount lenses concluded with the following codes for my four lenses:

Lightroom stores lens correction profiles, which correct for vignetting and distortion, for the first three. Strangely the Tele-Elmarit is missing.

While 6-bit coding corrects for edge color effects in-camera, there is still a need to apply lens corrections in LR or LRc for the best results. Ordinarily this is done manually, frame by frame, a very laborious approach. You have to check the lens maker and then choose the correction profile from a very long list, one frame at a time. Not good.

Here is how to have Lightroom do that automatically when the files are imported. Even if the imported files were made with more than one lens, the correct profile will be applied to each, along with chromatic aberration correction. Here’s the process.

Take a picture with each of your 6-bit coded lenses and import those into LR or LRc. Go into the Develop module on the first image and scroll down to the ‘Lens Corrections’ pane at right. Check the first two boxes as shown below. My examples are specific to the lenses I own. Choose as appropriate for yours.

21mm f/3.5 Voigtländer Color-Skopar Aspherical VM:

• Click on ‘Make’ and choose ‘Voigtländer’
• Click on ‘Model’ and choose ‘Voigtländer VM 21mm f/3.5 Color-Skopar Aspherical’ from the long list
• The correct Adobe profile will appear in the box ‘Profile’
• Click on the drop-down ‘Default’ above under Setup
• Click on ‘Save New Lens Profile Defaults’
• You have now instructed LR that every time it’s importing a file with the 6-bit code for the 21mm f/2.8 Elmarit-M to apply the profile for the 21mm f/3.5 Voigtländer VM Color-Skopar lens.

The next time you import a file taken with the Voigtländer lens, the correct correction profile will be applied along with correction of chromatic aberrations.

Now repeat this process for files taken with your other lenses, selecting the appropriate Make and Model each time. Here are my settings for the other three lenses I own with 6-bit coding. Amazingly LRc has corrections for the two Canon lenses, each over 50 years old:

35mm f/2 Canon LTM:

50mm f/1.4 Canon LTM:

90mm f/2.8 Leitz Tele-Elmarit:

In the case of the Tele-Elmarit there is no lens profile stored in LRc so I chose the one for the 90mm f/2.8 Elmarit-M which is very similar. Both lenses are almost distortion free so you really do not have to check the ‘Enable Profile Corrections’ box, but you still want to correct for chromatic aberrations.

Now on your next import these profiles will be applied automatically. The next step is to correct the lens’ names in EXIF data using the tool I describe here which takes little time and allows the serious business of post-processing to commence.