D-Lux 4 colour fringing that Leica could and should correct?

[macgarvin]

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The D-Lux 4 is a wonderful camera. You're welcome to take a look at some from dng files quickly processed mainly in Apple Aperture here, taken in the wonderful winter low angle light here now in Scotland.

 

Nevertheless - RAW files processed through Capture One have a significant issue with chromatic aberration. See first and second image at the bottom, a crop from bottom left of the photo - taken outside the backdoor yesterday in Glenlivet. To me, depending on the nature of the picture, this is a noticeable distraction in a print both as fringing and by giving a purple colour cast to outlying parts of the image. This is present through the range of focal lengths and at higher f numbers.

 

This is correctable in lightroom (see third and fourth images), where one can easily make a better job on the corner of an image, even uncorrected for barrel distortion, than that arising Capture One - ie a better result even though the initial state of the chromatic aberration is worse.

 

This is not good - in any circumstances - and especially as the facility for chromatic aberration is disabled in the version of Capture One provided with D-Lux 4

 

My question is this. Could (physics!), and should, this be automatically corrected by a revision of the firmware? (D-lux 4 allows firmware updates)

 

My reasoning is - Crops and corrections for barrel distortion happen through all focal lengths of the zoom. These manipulations are identical for the jpg produced in the camera (than may never see Capture One) and raw files that are displayed within Capture One. That (necessarily?) means that this is worked out in the camera and information is being passed over from the camera to the outside world in the rwl files (?) which any raw processor can take advantage of if it knows how to do so. Therefore, could exactly the same be done for handing over information for automatic correcting for chromatic aberration - or is this more complex than correcting for barrel distortion, for example perhaps because it depends on subject distance and f-number? What do the jpgs look like for chromatic aberration - I'm sorry to say I've haven't looked - which might give a clue?

 

If it can be done, I'd say it should be, instigated by Leica if not by Panasonic. Somebody somewhere along the line has been paid probably not a vast amount to deal with correcting barrel distortion, and I'd say it was worth paying them some more to make a better job of dealing automatically with ca as well if this is possible.

 

If you want to play around with the orginal files you can download the .rwl file, the full sized max quality jpg from Capture One, the .dng file, and the jpg from lightroom. Go here and select folder 'D-lux 3 and 4 comparison and the file number is L1000988 etc. Incidentally, it was deep twilight when this was taken, at f2 and 1/20, iso 80, which shows just what a great camera this is. You will also see a number of others, including L1000835 (fifth image below), which shows just how remarkably sharp the lens is at f4. And there is a whole range of more colourful shots at the link at the top.

 

Malcolm

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[Guest volkerm]

Did you check the JPG output?

 

I found that my D-Lux3 does remove CA in the JPG files very efficiently. In the RAW files, there is no automatic CA removal, of course. That is one reason for me to prefer JPG over RAW with the D-Lux3.

[Grigorij]

Capture One version 4.5.1 Pro has a function to remove purple fringes.

[robertwright]

Capture One version 4.5.1 Pro has a function to remove purple fringes.

 

it is ironic that the pro version of capture one would be needed to correct CA, fringing and distortion of raw files and Leica only chooses to ship the C1 lite., when they are asking double for the price of the camera over Panasonic!!

 

For the extra 400$ they should include capture one pro, you'd think no?

 

yet another example of Leica treating their customers like chumps.

 

more ironic is that I'd buy the dlux 4 for the camera and to get a pro license at the same time, that would be a better value.

 

guess I'm a chump...

[steve_l]

And Silkypix Raw Converter, included with the LX3, removes CA automatically.

 

It remains to be seen what Adobe ACR will do in the next release....

[mhoersch]

For the extra 400$ they should include capture one pro, you'd think no?

 

Or they might even go so far as to make a decent lens?

[robertwright]

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Or they might even go so far as to make a decent lens?

 

5mm f2? and a zoom. for 400$? I don't think so. There is always the summilux 24 coming out at 6500$...

[Grigorij]

And Silkypix Raw Converter, included with the LX3, removes CA automatically.

 

It remains to be seen what Adobe ACR will do in the next release....

 

it is ironic that the pro version of capture one would be needed to correct CA, fringing and distortion of raw files and Leica only chooses to ship the C1 lite., when they are asking double for the price of the camera over Panasonic!!

 

For the extra 400$ they should include capture one pro, you'd think no?

 

yet another example of Leica treating their customers like chumps.

 

more ironic is that I'd buy the dlux 4 for the camera and to get a pro license at the same time, that would be a better value.

 

guess I'm a chump...

 

In the first I"m sorry for my English, I learn this language about only one year (I live in Poland). I think that Capture One is a poor software to convert Leica RWL-RAW. After converted I see big noise in a photo, particulary in the sky. JPEGs from Leica D Lux 4 are many better then RAW converted by Capture One. For me software Capture One is completely useless... I shoot JPEG and RAW (waiting for better software to convert RAW),

[Grigorij]

And Silkypix Raw Converter, included with the LX3, removes CA automatically.

 

It remains to be seen what Adobe ACR will do in the next release....

 

Silkypix don't removes CA automaticaly, you have to mark area when is purple fringing, whilst Capture One remove CA full automaticaly.

[macgarvin]

Thanks all for your feedback

 

Volkerm; I have attempted to check ca in in-camera jpgs. It appears much the same, although it was slightly difficult to tell, as I set sharpening to -2 expecting this to turn sharpening off completely (as some cameras), whereas what -2 does is introduce softening of the image. But I wouldn't want to burn the level of sharpening into the image, and would also want to keep RAW for other reasons, for example greater than 8 bit colour data, which allows recovery of shadow and highlight detail beyond that possible with an 8 bit jpg (see the picture below where it might have been difficult to pull back cloud and shadow detail, even more visible at full size)

 

Robert - I also agree that the pro version of Capture One should be included without question if Leica are going to persist with that relationship, but still I would never use it (other than to convert RWL to DNG raw files!) because it has fallen so far behind the curve in other areas - as Grigorij points out it is very weak in how it exacerbates noise when doing sharpening, about as good as a pre-CS version of photoshop (I'd currently rate Apple Aperture top, then Lightroom - though only lightroom/photoshop can correct for CA and only photoshop for barrel/pincushion distortion. When you get to the printing stage only Aperture and Photoshop allow softproofing, Aperture allows output sharpening for printing, but it is leap-froged if you buy the Photokit plugin for photoshop, where there are presets for different output sharpening for different types of paper and dpi final output . . . money money . . . I'd say Aperture was the closest to becoming a one stop package, on Macs at least, including onward website delivery of contact sheets and automated delivery of final image chose by clients, the light table facility, photoalbum production, all the things you need to do once you have some great pictures . . .).

 

But what I really would like is for Leica to be proactive with Adobe, Apple and all other major package producers and say 'Sorry, we are embarrassed at the delay and that the quality of some images do not fulfil their highest potential. What can we do to help? We will treat this as a priority'. It would be an interesting development if Leica did this independently of Panasonic.

 

If anybody knows anything about the technicalities of chromatic aberration, whether this allows automatic correction, and what data can and cannot be passed on from a camera in a raw file to allow automated correction, I'd still be interested to know.

 

Grigorij - you may know this, others may not - but it's not necessary to wait for Adobe ACR if you want to work with RAW, just create DNG raw files from your RWL files from within Capture One - Capture One then doesn't manipulate the RWL image in any way, rather it reverses the 'corrections' it makes for barrel distortion. You can then ues the DNG raw files in lightroom, aperture etc - and at least Capture One is very fast at doing the conversions. However I agree it will be great when this is all handled from within other packages (or Capture One provide an incredible upgrade).

 

Last, I do think the lens/camera package is pretty amazing for the price. Having processed the image below in Aperture - sharpening, local contrast, recovered highlight and shadow detail, followed by minor removal of CA and soft proofing adjustments in photoshop. It prints up more than acceptably to me at 17 inches wide on glossy paper.

 

Malcolm

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[Guest volkerm]

If anybody knows anything about the technicalities of chromatic aberration, whether this allows automatic correction, and what data can and cannot be passed on from a camera in a raw file to allow automated correction, I'd still be interested to know.

 

Hi Malcolm,

 

I have quite some experience on the lateral & longitudinal CA topic. Actually, you have raised two questions: how to remove CA, and how to handle that for RAW data.

 

Removing this kind of lateral CA, as seen in the example image, is easy. Basically, all you have to do is to apply some color dependent scaling to the image, around the image center, so that all colors are shifted back to the same point. (Longitudinal CA is a different story, not so easy to remove).

 

Fully automatic removal of lateral CA with RAW conversion tools does exist. For example, the Nikon Capture NX software automatically removes this type of CA from Nikon RAW files. This works even without any lens information (works with manual lenses where no lens data is available).

 

The point is that the CA removal is done in the RAW tool, not in the camera. The RAW data itself is what the name says: raw, unprocessed sensor data. I would expect a solution similar to what Nikon does: the camera does embed some extra metadata in the RAW files, in addition to the unprocessed sensor data, and then some special RAW tools (and only those) will use that extra piece of information to develop the image with additional corrections applied. And the other RAW tools will just skip that extra information and do a standard RAW development without the extra correction.

(BTW, I believe that this is what happens in your workflow, too, where you describe corrections that are "beeing reversed". I am sure that it is some metadata that you have removed during DNG conversion, so that you see the true unprocessed RAW data).

[mjh]

I have found no significant amount of visible lateral chromatic aberration in JPEG images shot with the D-Lux 4 – there is some CA at the wide angle end of the zoom range, but it isn’t distracting in any way. Longitudinal chromatic aberration (aka purple fringing) is a different matter. Ever since the Venus Engine II, Panasonic (und thus Leica) applied CA correction in camera whenever necessary, but this was and is limited to lateral CA and to JPEG files. Naturally, no correction is applied to raw data, leaving this as an exercise for the raw conversion software.

[macgarvin]

Thanks volkerm and mjh for the information - that's helpful.

 

I had a look at the Adobe DNG converter 5.2 treatment of the RWL image at the top of the thread. The same crop to correct barrel distortion as Capture One, but it looked to me as if chromatic aberration was also corrected. However, that's only based on inspection of one image . . .

 

Malcolm

[archi4]

Malcolm

I also discovered that Adobe Camera Raw seems to remove the CA and barrel distortion in my test shots and my first impression is that it removes the barrel distortion with less loss of detail at the left and right edges of the image than C1.

Maurice

[ho_co]

I also discovered that Adobe Camera Raw seems to remove the CA and barrel distortion in my test shots and my first impression is that it removes the barrel distortion with less loss of detail at the left and right edges of the image than C1.

Maurice, that's my experience as well. There's also a difference in color rendition. I don't know whether either is more accurate, but I usually prefer the ACR version.

 

But I just started working with Capture One two days ago, and with ACR 5.2 today, so there's still a lot to learn.

 

Imaging has turned a corner. Nikon put some lens correction tools into its software and now Panasonic has done the same. We used to think lens correction was optical; today it's software-based as well.

 

A parallel for those who remember the yellow boxes in which our slides were returned: For years, Kodak continually improved their cardboard mounts to hold the film flatter. Then one day they got the idea that the better way to go was to design lenses to match the film's curvature, and introduced curved-field lenses.

 

Until that moment, Leica always had sharper images on screen and admonished people that only glass-mounting could hold film flat. When Kodak started letting the film curl intentionally, even Leica came out with the oxymoronic "Colorplan CF."

[ho_co]

I had a look at the Adobe DNG converter 5.2 treatment of the RWL image at the top of the thread. The same crop to correct barrel distortion as Capture One, but it looked to me as if chromatic aberration was also corrected. However, that's only based on inspection of one image . . .

Malcolm--

Having converted a number of images in both ACR and Capture One, I agree that ACR does seem to do a better job (or offers the tools to do so) with chromatic aberration, as you said.

 

But the crops are a little trickier. When viewed in Bridge (with ACR):

DNG from Capture One doesn't include optical corrections.

DNG from ACR includes the corrections and looks just like the RWL in ACR.

TIFF from Capture One looks a bit stretched (or slightly flatter?), and may not be quite as sharp as the DNGs.

 

Or put the other way round:

Capture One's DNG includes the most information because it doesn't remove distortion.

Putting the ACR DNG through DNG Recover Edges reveals slightly more of the image than the ACR DNG, and noticeably less than the Capture One DNG, but without the distortion.

ACR's standard DNG is just a bit tighter.

Capture One's TIFF crops tightest.

 

To me, it looks as if either the Capture One TIFF overcorrects the barrel distortion, or the ACR DNG slightly under-corrects. Both the renderings look good, but the DNG includes just a bit more of the edges.

 

 

FWIW: DNG Recover Edges expands the long side of the D-Lux 4's 16:9 aspect ratio from 3968 to 4004 pixels and expands the short side from 2232 to 2250 pixels. Unlike other cameras, the additional pixels don't seem to be evenly divided. A much larger quantity of the 36 extra row pixels seems to turn up at the right end than at the left. The right end is just where DNG Recover Edges recovers garbage from DNGs produced by Capture One.The camera becomes more and more interesting!

[macgarvin]

Just to chuck an extra variable into the mix -

 

When I was working on these images with Lightroom 2.1 on mac, and transferring to photoshop CS3 for further work (soft-proofing adjustments), I found that my sharpening and contrast enhancements were not sticking if I had exported from within the LR 2.1 Develop module, had option clicked, and selected edit (in photoshop) in the dropdown menu to transfer the image over to PS. However, if I returned first to the Library module, and choose the export button (bottom left), then the transferred image had all of the modifications.

 

Has made me a bit leary . . . anybody else able to replicate this upon opening in PS CS3?

[macgarvin]

Capture One's DNG includes the most information because it doesn't remove distortion.

 

So perhaps worth hanging on to the current version of Capture One in case future updates of C1 make this crop tighter (i.e. Panasonic/Leica may be happier, although with care it includes useful working area)

[ho_co]

So perhaps worth hanging on to the current version of Capture One in case future updates of C1 make this crop tighter (i.e. Panasonic/Leica may be happier, although with care it includes useful working area)

Thanks for the suggestion! Very good point--I hadn't considered that option!

 

"Doing away with lens defects" would be a main goal of the manufacturer, but maybe not the best solution in all cases. As I've noted elsewhere, the slight barrel distortion sometimes gives a more natural looking image.

 

 

The more I experiment with the D-Lux 4's files, the more intrigued I become.

 

For example, DNG Recover Edges behaves differently on files of the different aspect ratios (not the case with the D-Lux 2). And it's interesting to have the various color renditions and lens corrections of Capture One and ACR as starting points.

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