LrC "Focus-Points" plugin straightens images by applying camera roll angle compensation

[Karsten]

Version 3.3 of the Focus-Points plugin introduces a new feature that straightens images by compensating for the roll angle if the camera was tilted when the photo was taken. This method can be applied to individual images or selections.

The plugin generally produces better and more reliable results when correcting levels than Lightroom's Auto Transform feature. This is because it responds directly to horizontal camera imbalance, rather than looking for and using reference information, which is often absent or unreliable in wildlife, sports and action shots.

Example: The photo has a roll angle of 2.5°. Applying a crop angle of -2.5° compensates for the tilt. Using the ‘Straighten Images’ tool produces the same result as entering the roll angle compensation manually in Lightroom’s ‘Crop & Straighten’ tool. You can then modify or even revert the compensation as desired:

[Ian]

What a good idea!

I'm looking forward to trying this.

Does it depend on the camera's level sensor being properly calibrated?

Ian

[Karsten]

Yes, of course. For good results, the sensor needs to be properly calibrated.

For Olympus/OM cameras, the RollAngle tag is recorded for the EM-1/5/10 (all Mark III) and later models, for which precision is not an issue.

If you find that your camera is (or was) systematically miscalibrated, there is an 'offset' setting to compensate for this.

[Bikie John]

Interesting. It looks similar in function to part of what Leica do with the Perspective Control feature, which also deals with the pitch angle (lens pointing up or down) to apply perspective correction. I have long thought that other manufacturers ought to offer something similar. Thanks Karsten for your efforts to bring it independently.

John

[Karsten]

I wasn't aware of Leica's Perspective Control feature. Although Olympus/OM and other manufacturers also store pitch angle, it would be difficult to use this for vertical corrections as there is no linear relationship between pitch angle and the 'vertical' setting in Lightroom's 'transform' section.

I won't deny that I'm hesitant to implement features that I don't find useful for my workflow 😉 For complex perspective corrections, such as those required for architectural shots, I prefer to draw four guides 😄

[Bikie John]

The Leica one works well. They worked with Adobe to make it work with the "Guided" perspective transform so if the data is there it will correct for both pitch and roll with a single click (or even apply it by default if you have all the appropriate options switched on).

The part of it that I find most useful about it is in the camera itself, so sadly way out of reach of a Lightroom plugin. It will show you in the viewfinder what will be in the frame after correction. I find this really useful, as it always surprises me how much you lose in applying a normal perspective correction.

John

[Karsten]

It will show you in the viewfinder what will be in the frame after correction. I find this really useful, as it always surprises me how much you lose in applying a normal perspective correction.

I always wonder about this when I'm shooting buildings that don't fit in the frame. Olympus/OM users have keystone, but it's manual and doesn't work with HDR bracketed shots, for example, which I use a lot when shooting architecture.

[Ian]

Does the plugin require manual updating?

Ian

[Karsten]

Does the plugin require manual updating?

Yes, at this time. There is no standard infrastructure or logistics in place for this, so each plugin creator needs to devise their own procedure. This is on my list of to-do's.