EOS R5 Mark II When to use Distortion Correction?

[boelens218]

Distortion correction is disabled by default on the r5 mark2. In what situations would you want to enable it?

I plan to only use the single lens I have which is the 24-70mm F2.8. 

I use Affinity Photo 2 to edit my cr3 images, should I use the "lens correction" (profile for my lens) and the "remove lens vignette" features? They are both enabled by default. 

Thank you,

[boelens218]

I also took the same exact picture with and without distortion correction enabled on my camera. I understand when the distortion correction is enabled on the camera and you record in raw+jpg, the distortion correction is applied to the jpg image only. For the raw file, it's only applied to the jpg preview and additional metadata is provided to let software know that distortion correction is applied. However, software (Photoshop, Affinity, etc.) doesn't actually use the distortion correction from the camera with the metadata. Instead, the software just reads that metadata to look up the lens and uses its own distortion correction. When distortion correction is disabled on the camera, raw files still have other metadata software can use to look the lens and apply its own distortion correction. Therefore, it literally makes no difference if distortion correction is enabled or disabled on the camera for raw files. This is because the software is going to read the available metadata to look up the lens and apply its own distortion correction. Meaning, software never uses the exact, 100% accurate distortion correction from the camera when enabled. Please let me know if I understand that correctly.

Moving on, I took the raw file (with/without distortion correction enabled on camera, doesn't make a difference because the software is going to use its own correction anyway) and applied the distortion correction in Affinity. Then, I compared it to the jpg with distortion correction enabled on the camera. The distortion correction looks pretty exact to me. What do you think? I'm just trying to figure out if the distortion correction is being done accurately in Affinity. For example, I don't want to apply the correction with Affinity if its wrong or misidentifies my lens.

I will not use the Canon DPP software, I only used it as a test to compare the distortion correction results. The software is so unresponsive and I'm just not a fan. It literally took about 25 seconds for the distortion correction to appear on screen. That's no disrespect to Canon, I just wanted to make that clear in case someone suggests I just use DPP instead of Affinity.

Camera (With Distortion Correction)Affinity (With Distortion Correction)

[SignifDigits]

It appears to me that DPP is doing the better job - just slightly straighter on the far fence top pole.  It also is correcting vignetting.  What Affinity might or might not be doing would only be speculation, but I think it's clear it's not performing the same operation that DPP is on the image.

[SignifDigits]

As on the motorcycle picture Canon is doing a better job of correcting the Vignetting.  I also see a slight difference in the pincushion correction on the TV on the wall.  I do not believe the same algorithm is be applied to the digital image.  That said, the Lensfun correction is developed independently from Canon so they are almost certainly not the same to begin with.  Thus, it is really impossible for us to tell you authoritatively what the Affinity software is or is not doing.

I know that's not the answer that you wanted and you came to us hoping that we  to be able to resolve your frustrations with Affinity and not knowing for certain that the correct RF lens correction is being applied.  I think to answer your question authoritatively your only option might be to somehow borrow an EF version of the lens, shoot it and compare the Affinity images for the RF and EF lenses side by side.

I think feel I can confidently tell you that the Canon lens correction is different than the lensfun correction that you are getting in Affinity.  And, in my opinion at least,  Canon is better.

Thanks for all of the info on the software and your thoughts on DPP.  I had the same experience on DPP on older Windows based hardware and when I wasn't processing the file directly on my system internal hard disk and/or solid state disk drive.  That put me off of DPP as well at the time.  Thankfully I don't have those same performance issues with my newer computers.  

[Peter]

You can download Irident C-Transformer. it will convert Canon raw files and read Canon lens correction. Actually the only third-party software I know about that can do that.

Output will be a demosaiced DNG you can load in Affinity. Take a look and compare. The demo will work, but it will add watermarks on the pictures.

[ebiggs1]

For myself, I use Photoshop and Lightroom and they are the apps I recommend everyone use. They are the industry standards. All pro shops use PS and LR. I have never used Affinity nor do I ever see me using it. I apply lens correction to every image that is u/l to my computer. That's me but my background was in business where the photos were sold so only the best or the best I could offer would work or acceptable.

However, there a two opposing interests here as not every photo needs lens correction. For the most part pixel peepers are the ones that feel it is absolutely necessary on every photo. But in reality a snapshot photo, like the samples you offered, probably do not get any or much real world improvement from lens correction. I would never recommend not using it since it is an automatic preset that is applied upon u/l. It will never hurt or harm the photo.

[jrhoffman75]

For the lower cost RF lenses Canon is relying on forced lens correction in camera. It can’t be switched off in camera. Helps keep cost down. 

[boelens218]

I didn't use the "remove lens vignetting" feature in Affinity for any the examples. I only wanted to show the distortion correction. 

I must of forgot to disable the vignette correction for the DPP example. Either way, I was only comparing the distortion correction. Yes, I agree that DPP will provide the most accurate distortion correction. Each software program will use its own distortion correction which will be slightly off from DPP.

However, the distortion correction with Affinity appears very close to DPP. Like I said, I could never use DPP in its current state. Its very unresponsive and I have a very powerfull PC. Plus, I don't really like the UI.

[boelens218]

You are correct, not every image needs distortion correction. This is why Canon does NOT recommend enabling on the camera unless you have a very, very wide angle lens. This is because it can and will apply lens correction to images that don't need it which will harm the image. This only applies when recording in formats other than raw. When recording in raw, you still have the choice to use distortion correction in software even though its applied on the camera.

I will never use PS or any Adobe product and can't believe you recommend it. Adobe is bad news and they are losing customers everyday. I was lucky to get a license for Affinity Photo when I did because they no longer offer them. I really like Affinity Photo 2.

[boelens218]

If your recording in raw, having distortion correction enabled, whether its forced or not, will not imapct the actual raw image. You still have the choice to use the correction in software.

[boelens218]

Thank you everyone for your very helpful feedback. I also spoke to a very helpful technician at Canon. Let me just say, she really knows her stuff.

She explained to me that distortion correction can work and improve some images, but it can also have a negative effect with other images. This is why Canon does not recommend enabling on the camera unless you have a very wide angle lens. Again, if your only recording in raw, having it enabled on the camera doesn't really do anything. You still have the choice to use it or not in the software. Plus, you can even fine tune the amount of distortion correction with software.

I was able to send her the same sample images and she gave me her professional opinion. She thought the correction improved the image of the dog and the motorcycle, but made the others worse. 

This actually didn't help me all that much because I want to use the correction for all my images or none of them. As I explained, I have trouble knowing if the correction makes things worse or better. She did tell me if its all or nothing for me, she recommends not using the correction, at least for my lens and that seems like what I'm going to do. Although, if your someone who can tell if the correction makes things better or worse, its best to use when it can make an improvement. At the end of the day, distortion correction is both objective and subjective.