D-Lux4 Barrel Distortion

[jbm]

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At the Imaging-Resource review of the LX3 / D-Lux4 it mentions that barrel distortion is corrected by the camera in JPEG, but not in Raw. At the time of the review it said the only Raw converter that auto corrected the barrel distortion was Silkypix.

 

Fot those of you that have the D-Lux4, will the Leica supplied software or PS software do this correction in Raw also?

 

-Jim

[ho_co]

Jim--

This has been covered in a number of forum threads. Summary:

 

Leica supplies Capture One with the D-Lux 4. Working from the RWL file:

1) Capture One completely corrects the lens aberrations in TIFF output.

2) Capture One leaves lens aberrations uncorrected in DNG output.

 

Considering Adobe software: Because for the first time the RW2/RWL files include lens correction instructions, Adobe has implemented a de-mosaicked DNG format originally defined in the DNG definition but not previously used. Thus, Adobe's Camera Raw and Lightroom and their free DNG Converter all correct the camera's lens aberrations to a slightly lesser degree than Capture One's TIFFs, but to a degree that in many cases looks better than the completely square TIFFs of Capture One. These corrections occur automatically and apply to all output from these programs.

 

So the answer to the question is that the Leica-suppplied software does correct the images; that there is other software available which also corrects the camera's output; and that the information you report is out of date.

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[jbm]

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Thanks Howard for your very detailed and informative answer.

 

-Jim

[ho_co]

Jim--

You're welcome. I hope it's helpful and I didn't mean to come across high-handed.

 

The brilliance that Panasonic showed in putting image corrections into the raw files has forced a lot of unforeseen changes that are still working themselves out.

 

I only hinted above at Adobe's machinations in producing DNGs from these cameras. See Adobe - Adobe Camera Raw and DNG Converter : For Macintosh : Adobe DNG Converter 5.2 update and check out the (long) footnote beginning with

*With the release of Camera Raw 5.2 (and upcoming release of Adobe Photoshop® Lightroom® 2.2), there is an ...

[rycm]

Lot's of barrel distortion. ACDSee Pro can read the LX-3 RAW files, and DOES NOT do any processing on it to correct the distortion. LR 2.2 takes the RAW and corrects the barrel distortion. I prefer it corrected in LR. Panasonic did a great job in the in camera correction. And now with LR, it is also done for RAW.

 

You can see the difference between un-corrected RAW-JPEG from ACDSee and that of LR.

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[jbm]

Thanks for the comparison Rycm, and you have a beautiful family.

 

Best

Jim

[gtravis]

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Jim--

This has been covered in a number of forum threads. Summary:

 

Leica supplies Capture One with the D-Lux 4. Working from the RWL file:

1) Capture One completely corrects the lens aberrations in TIFF output.

2) Capture One leaves lens aberrations uncorrected in DNG output.

 

Considering Adobe software: Because for the first time the RW2/RWL files include lens correction instructions, Adobe has implemented a de-mosaicked DNG format originally defined in the DNG definition but not previously used. Thus, Adobe's Camera Raw and Lightroom and their free DNG Converter all correct the camera's lens aberrations to a slightly lesser degree than Capture One's TIFFs, but to a degree that in many cases looks better than the completely square TIFFs of Capture One. These corrections occur automatically and apply to all output from these programs.

 

So the answer to the question is that the Leica-suppplied software does correct the images; that there is other software available which also corrects the camera's output; and that the information you report is out of date.

 

Howard (and others):

 

When I first got my D-LUX 4 (three months ago) I attempted to verify what seemed to be the prevailing wisdom at the time -- that the camera corrected barrel distortion on camera-made JPEGs but that the RAW files were un-corrected and that the version of Camera One that came with the D-LUX 4 would NOT (unlike Silkypix) correct for barrel distortion.

 

I took some pictures at the time that seemed to confirm exactly that.

 

Yesterday, I decided to dig a little deeper. I took a picture of an outside brick wall at 16:9 aspect. The camera was set to produce BOTH a JPEG and RAW.

 

I then processed the RAW file into JPEGS using Adobe Photoshop as well as Camera One. The results?

 

1. There is significant (to me, at least) barrel distortion in the JPEG made from a RAW using Photoshop. This I expected. It was (and is?) my belief that Photoshop performed no barrel distortion correction.

 

2. There is significant barrel distortion in the JPEG that the camera made (and supposedly corrected). In fact, the amount of barrel distortion in the camera-made JPEG is IDENTICAL to the distortion in the Photoshop RAW-JPEG file.

 

3. There is no barrel distortion in the JPEG processed from the RAW file by Camera One.

 

From that I initially concluded that the camera was doing NO barrel distortion correction, even in JPEG mode.

 

Now, after having read your post, I am wondering if the actual amount of barrel distortion in the RAW file is even more than I am seeing in the Photoshop processed RAW and the camera JPEG. That the camera processes out the distortion in the JPEGS but not quite all the way and that Photoshop is also processing out the distortion but only to the exact same degree as the camera is.

 

Is that possible?

 

Here is the picture:

 

http://www.littlebear.com/UNCORRECTRAWTOJPEG.jpg -- That's the RAW camera image as processed by Photoshop into a JPEG

 

http://www.littlebear.com/CAMERAJPEG.jpg -- That's the JPEG as the camera made it -- note that the amount of barrel distortion is equal to the above picture

 

http://www.littlebear.com/RAWTOJPEG.jpg -- That's the RAW camera image as process by Camera One into a JPEG - note no barrel distortion

 

The camera is running Firmware Version 1.2 and Camera One ver 4.7. When I did my initial tests three months ago the camera was at Firmware Version 1.1 and I think the version of Camera One was 4.5

 

Thanks,

 

greg

[gtravis]

Answered my own question. Yes, Photoshop is doing barrel distortion correction on D-LUX 4 raw images. And it appears to be using the exact same distortion correction as the camera uses internally when making JPEGS.

 

I was able to convert the raw image to a jpeg using dcraw instead of Photoshop. Here is the photograph the camera actually took: http://www.littlebear.com/REALLYRAW.jpg

 

Holy smokes that's a lot of barrel distortion. So I can sum up what I now know:

 

Shooting 16:9 format on a D-LUX 4 produces HEAVILY barrel-distorted images.

 

Both Photoshop and the camera's in-camera JPEG processor correct most, but not all, of that distortion.

 

Camera One will fully correct the barrel distortion (at least as of version 4.7).

 

greg

[nemeng]

Answered my own question. [snip]

 

Shooting 16:9 format on a D-LUX 4 produces HEAVILY barrel-distorted images.

 

Both Photoshop and the camera's in-camera JPEG processor correct most, but not all, of that distortion.

 

Camera One will fully correct the barrel distortion (at least as of version 4.7).

 

 

You can also fully correct the barrel-distortion ("B-D") in post using things like "Panorama Tools" - which is what I do.

 

My current workflow: (1) Shoot RWL+JPEG (2) Use the JPEGs for image preview on a computer (3) process the keeper RWLs using RPP (I'm on a Mac) into colour corrected 16-bit TIFFs (4) Correct the B-D and lens chromatic aberration in Photoshop using "Panorama Tools" plug-in.

 

I have written a Javascript Photoshop script to automate step 4 above. I have three user-selectable B-D settings: "strong", "mild" and "none". At the same time I have also thrown in a little sharpening and hue/saturation enhancement.

 

The above works well for me and produces acceptably sharp and corrected images. YMMV!

 

BTW why have a "none" setting for B-D correction? This is when I want to use the images in PTGui for panorama stitching (where the B-D will be corrected automatically) Why have a "mild" setting? For shots taken at longer focal lengths or else when I don't feel the need to fully correct B-D. After all, some of us take photos of things other than empty brick walls... :?)

[ldm92]

Howard (and others):

http://www.littlebear.com/RAWTOJPEG.jpg -- That's the RAW camera image as process by Camera One into a JPEG - note no barrel distortion

 

It's definitely better, but to me, there still appears to be some; look at the right-hand corners. Brick walls are not great examples of straight lines, still, if you place a straight edge along the horizontal brick lines (near the top or bottom of the image), you'll notice some distortion. Of course, some of this could be due to the camera not being perfectly square to the wall.

[gtravis]

It's definitely better, but to me, there still appears to be some; look at the right-hand corners. Brick walls are not great examples of straight lines, still, if you place a straight edge along the horizontal brick lines (near the top or bottom of the image), you'll notice some distortion. Of course, some of this could be due to the camera not being perfectly square to the wall.

 

The camera wasn't normal to the wall (hey, I tried).

[sarangiman]

ho_co wrote above:

 

2) Capture One leaves lens aberrations uncorrected in DNG output.

 

My question is: how did you even get Capture One to output a DNG from a Leica RAW file? I just tried on Capture One Pro 4.8 and it tells me that outputting to DNG is not supported. A quick Google search confirms that folks can't convert Leica D-LUX 4 RAW files to DNG in Capture One. So I'm wondering if you yourself have somehow been able to output the distortion uncorrected DNG.

 

Why am I so interested in distortion UNcorrected DNGs? Because:

 

1.) I hate the effect that distortion correction has on people's faces. It's fine & good to straighten a brick wall, but straighten a person's face who's not centered, and the effect is as if they gained 50 pounds. Why would I want this?

 

2.) ACR performs so much noise reduction that I'm left with a soft image. I'd like a demosaiced DNG that does *not* have the lens distortions applied.

 

 

Cheers,

Rishi

[sarangiman]

gravis,

 

I just noticed that you say you used dcraw to output a lens distortion UNcorrected JPEG.

 

Do you have any idea how to output, using dcraw, a demosaiced DNG that does *not* have any distortion corrections (please see my post above as to why I dislike the corrections)?

 

If not, at the very least, I'd be extremely appreciative if you were to point me in the right direction re: just using dcraw to make distortion uncorrected TIFFs from my RAW files!

 

Thanks in advance!

Rishi