Retaining the pixels discarded by ACR lens correction

[M.Chapman]

As a long term user of PS/LR/ACR I sometimes want to recover the pixels that get discarded by the automatic lens distortion correction. ACR allows the lens distortion correction to be turned off for many cameras and lenses, but not for all (e.g. my Sony RX100 Mk III, Lumix G5, G7). These cameras store the level of lens correction required inside the RAW files as Op Codes which ACR automatically applies. The number of peripheral pixels discarded by these corrections can be significant, as illustrated by the 2 images below. The darker background image shows the actual pixels captured by the sensor. The lighter central overlay shows the pixels that are retained during ACR lens distortion correction.

 

Sony RX100 Mk III @ wide angle.

Lumix G7 with 14-140 lens @14mm

 

I've no idea why more pixels than necessary are discarded with my Lumix 14-140 lens @ 14mm. But the ACR developed image matches the in camera JPG so it must be down to the Op Code values set by Panasonic and stored in the lens firmware. The same thing happens with the Lumix 7-14mm lens. 

 

Previously, if I wanted to retain the discarded pixels, I had to use a different RAW image processor (e.g. DXO, Capture 1 etc.) which allows the distortion correction to be turned off, or I had to manually edit the RAW file Op Codes with an EXIF Editor.

 

But now I've found a simpler workaround for use with ACR.

 

Step 1 - Convert RAW file to DNG format using Adobe's free DNG convertor https://helpx.adobe.com/uk/camera-raw/using/adobe-dng-converter.html

Step 2 - Strip the Op Codes from the DNG file using the DNG Cleaner App (about £10) from the App Stores 

     https://apps.apple.com/us/app/dng-cleaner/id1205138449 or

     https://apps.microsoft.com/store/detail/dng-cleaner/9NK3SQ79XR4D

Step 3 - Open the "cleaned" DNG in ACR where it will now open without any distortion correction applied.

 

This allows me to access the full "wide angle view" using my preferred RAW editor and then manually correct distortion and crop only if needed.

 

Mark

 

Edited October 5, 2023 by M.Chapman

[spacecadet]

I have the correction turned off in the camera. But I usually do then perform the correction in LR. Certainly for images like your examples of structures where distortion is obvious. I might not for a landscape.

[M.Chapman]

23 hours ago, spacecadet said:

I have the correction turned off in the camera. But I usually do then perform the correction in LR. Certainly for images like your examples of structures where distortion is obvious. I might not for a landscape.

 

Out of interest, which camera is that?

My Lumix cameras only offer lens shading (vignetting) comp on/off, but I think that only affects the in camera jpgs. The RX100 MkIII doesn't appear to have vignetting or distortion  ON/OFF option (at least I can't find it in the myriad of menus).

 

It's good that Adobe have said ACR will allow automatic distortion correction to be disabled (adjusted down to 0%) on any new cameras they support. ACR now allows removal of  automatic distortion correction on my current Lumix G100 RAW files. But not on my older Lumix G7 and G5 RAW files. Hopefully Adobe will go back and add the feature in for older camera RAW files too, but until then the "DNG Cleaner workaround" above will suffice.

 

Mark

Edited October 7, 2023 by M.Chapman

[spacecadet]

3 hours ago, M.Chapman said:

 

Out of interest, which camera is that?

My Lumix cameras only offer lens shading (vignetting) comp on/off, but I think that only affects the in camera jpgs. The RX100 MkIII doesn't appear to have vignetting or distortion  ON/OFF option (at least I can't find it in the myriad of menus).

 

It's good that Adobe have said ACR will allow automatic distortion correction to be disabled (adjusted down to 0%) on any new cameras they support. ACR now allows removal of  automatic distortion correction on my current Lumix G100 RAW files. But not on my older Lumix G7 and G5 RAW files. Hopefully Adobe will go back and add the feature in for older camera RAW files too, but until then the "DNG Cleaner workaround" above will suffice.

 

Mark

 A58. I have 3 settings for shading (presumably vignetting) CA and distortion. The first two are on "auto", I don't think I've ever changed them, and the last is off. I don't know if the menu layout is similar but they're on the last (4th) page of the settings menu (with the cogwheel).

I had a memory that the settings showed in the viewfinder but I've just checked and they don't, so using it might be a bit of a shot in the dark.

Edited October 7, 2023 by spacecadet

[M.Chapman]

22 hours ago, spacecadet said:

 A58. I have 3 settings for shading (presumably vignetting) CA and distortion. The first two are on "auto", I don't think I've ever changed them, and the last is off. I don't know if the menu layout is similar but they're on the last (4th) page of the settings menu (with the cogwheel).

I had a memory that the settings showed in the viewfinder but I've just checked and they don't, so using it might be a bit of a shot in the dark.

Those options aren't there on the RX100 MkIII, probably because it's a fixed (rather than interchangeable lens) zoom lens camera. 

 

Mark

[spacecadet]

3 hours ago, M.Chapman said:

Those options aren't there on the RX100 MkIII, probably because it's a fixed (rather than interchangeable lens) zoom lens camera. 

 

Mark

That makes sense.