GX85: Lens Correction and other question

Antigen

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Hi to all!

Finally i bought my first MU-43 camera, a Lumix GX80 + 12-32mm , and the difference with my old canon is very very important :)

I have a question about the lens correction (Color Aberration + Vignettinin etc... ) , i shot i RAW+JPEG and i'm using Silkypix 9 Panasonic Edition to develop my photos.

(I'm evaluating if using the JPEG or proceed with the RAW---->Silkypix develop.)

My question is, when i shoot, the camera automatically applicate the Lens correction or i need to enable something? The lens correction is applicated automatically on the JPEG and to the RAW file or not or only to the JPEG?

I tried to ask to Silkypix but they don't reply :-(

Sorry for the question, but for me this a real new world.

If in future i will buy another lens for my Lumix but produced by Olympus (I see a good Zoom Lens 40-150mm at cheap price), the lens correction will work or only to Lumix lenses?
 

nsd20463

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There is nothing to enable on the camera.
The camera applies the lens corrections to the jpeg.
The raw file contains the raw sensor data (so no corrections) AND a description of the needed corrections. Silkypix and other software (LR) reads both and applies the corrections to the raw data.
Some (but not all) raw development software allow you to see the uncorrected raw file. For example RawTherapee and Darktable.
 

Antigen

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In conclusion when i shot with RAW, the correction is included into the file and when i open with Silkypix it automatically correct the lens with default data stored into the raw file?

And if i will use a "non-Panasonic" lens correction will happen?
 

wjiang

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Think of RAW and JPEG separately. The correction data is always available and is actually supplied by the lens (irrespective of brand, as long as it is a native lens with electronics in it). The in-camera controls just affect JPEG as to whether the vignetting correction is applied to the JPEG or not.

Meanwhile, a RAW converter has the data available and can choose to apply it or not. Some allow vignetting and distortion correction to be independently enabled or not, while others like ACR unconditionally enable it.

I'm not sure what SilkyPix does. Because it doesn't use the same development engine as the camera, it will not look quite the same as the in-camera JPEG.
 

Antigen

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In conclusion when i open SilkyPix… it applies automatically the lens correction gived by the RAW file, not important if i use a Panasonic or Olympus lens?
 

Antigen

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In conclusion the lens tell to the body of my lumix body what is the lens correction and it generate a raw file with it inside.

When i open Silkypix it read and apply automatically the correction. True?

I don't understand why silkypix refuse to reply to this info, it applie or not the correction automatically?
 

Antigen

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Another question, let's assume that we buy a new lens in the year 2025, we are using an old GX80.

The 2025 MU43 lens will tell to the body the lens correction or not? Why for example with Canon when a new lens the softare that canon give with the camera is update with the new Lens profile, but how work the MU43 world? Will silkypix used in 2025 be capable to read the setting ?

The "future" lens tell to the old body the setting to correct the aberration or no? I know that is a strange question but i ask becaus i think is important to undersand the future proof of this technology.
 

wjiang

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The types of correction data specified by the m4/3 interface, namely distortion and vignetting, are standardised, so future lenses will work the same way for those parameters. They may decide to introduce extra correction data to future versions of the m4/3 interface but given they haven't in all this time, I doubt it. The latest 12-200 lens will have it's distortion and vignetting corrected just as well on a now old E-M5 body.
 

Antigen

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But it's required that the software that i use to develop the RAW know the lenses? Or not?

For example if you try to correct a photo in the "canon world" with their DPP software, if the software don't know the lens= no correction.

Thanks for this interesting thread
 

wjiang

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But it's required that the software that i use to develop the RAW know the lenses? Or not?

For example if you try to correct a photo in the "canon world" with their DPP software, if the software don't know the lens= no correction.

Thanks for this interesting thread
The software (whether in camera or on PC) just has to know how to read m4/3 interface specified lens correction data. It doesn't matter what the lens is. It's the advantage of having a standard interface rather than a proprietary one.
 

ToxicTabasco

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Yes, one thing Lumix cameras do is use a computational data from Panasonic lenses with their Lumix bodies, and use the lens' data to automatically apply the lens' known specs and use that data to make adjustments for the lens perspectives, diffraction, as well as the sharpness and speed of the contrast DFD auto focus. I suspect it's one of the reasons why Lumix continues to use the Contrast AF system AKA Depth From Defocus (DFD), which allows the AF and Lumix camera body to nail focus with speed and accuracy better than a phase detect AF system.

But then I could be wrong, and Contrast AF systems has no impact on the function of the raw & JPG files they produce.
 

archaeopteryx

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But it's required that the software that i use to develop the RAW know the lenses? Or not?
It's required. However, the way in which it's required depends on the software.
  • Silkypix, Adobe Camera Raw, and perhaps some others read and apply the lens corrections embedded in an Olympus or Panasonic raw file.
  • Partly because Panasonic and Olympus haven't made lens corrections an open standard, LibRaw based tools (darktable, RawTherapee, and quite a few commercial raw developers including some versions of Silkypix) usually attempt to work around the closed nature of the μ43 specification by matching the body and lens names in the EXIF to a lensfun profile.
Part of the problem with the latter approach is commercial operations are happy to take profit from use of lensfun but don't give back to the system. More about how @junkyardsparkle is holding that together almost singlehandedly for all of on a volunteer basis in this thread.

I don't understand why Silkypix refuse to reply to this info, it apply or not the correction automatically?
It's not just Silkypix. All of the closed source raw developers seem pretty cryptic. Probably the simplest way to get answers is to pixel peep test images chosen to show distortion, vignetting, and chromatic aberration.

Perhaps the most robust way of dealing with the photographic industry's chronic dysfunction over this is to work with jpegs by default and fall back to raws when jpeg doesn't support the desired adjustment latitude in post. People get very attached to raw toolchains, though, so we have a vibrant ecosystem of other threads going round about variations on this. For example, here, here, here, here, and here.

They may decide to introduce extra correction data to future versions of the m4/3 interface but given they haven't in all this time, I doubt it.
True, it's not exactly like lenses have developed new kinds of aberrations over the past several hundred years. I'd assert, however, that the general photographic industry's present approach to lens corrections is technologically naive compared those used with optical systems in other areas such as astrophotography and microscopy. For example,
  • Among the five Seidel aberrations, current lens correction mechanisms don't attempt to remove spherical aberration, coma, astigmatism, or field curvature. Field curvature is probably more complicated than is worth getting into here but spherical aberration, coma, and astigmatism are all easily corrected by deconvolution with the lens's point spread function (PSF). All major lens design software computes PSFs so really the only reason not to apply at least baseline correction is because manufacturers don't publish datasets indicating the PSFs across the frame, at different focus distances, and at different zooms. Perhaps manufacturers are quietly applying some of this in SOOCs, perhaps not, but the only general photography tool I'm aware of to attempt any such correction in post is piccture+, which is an on again, off again effort.
  • Diffraction correction is another deconvolution with an idealized PSF based on the f/stop at which an image was acquired. Most bodies now have some support for this in SOOCs. Perhaps some are even smart enough to account for variation in the presented aperture across the frame. Raw developers generally lack corresponding corrections, however, and I'm not aware of any efforts to support recovery from high f/stops forced by use of substantial magnification in certain types of macrophotography. Which is especially odd for, say, Olympus, as their microscopy division invests heavily in the area. (Nikon, Zeiss, Leica, and Rodenstock/Qioptiq are also all involved in microscopy.)
  • Chromatic aberration correction is only lateral. Longitudinal (depth) correction isn't done. However, this is just another deconvolution and any camera with an array of PDAF points or DFD information has depth information across the frame. In most cases it could be argued the array is coarse and error residuals will result, but it's unlikely the residuals will be worse than no correction so, overall, it'd probably be a net improvement. (In the case of Canon dual pixel every pixel notionally has depth information, so it's harder to make this argument.)
Embedding a reasonable amount of such information in a raw would probably take a few hundred kB before compression. Since raws are already 20+MB it'd likely be less than a 1% increase in file size, which is no trouble.

Considering the industry is still struggling to implement basic corrections 15+ years after the opportunities became obvious I agree it's unlikely any of this will happen in μ43. Some future system, maybe, but I haven't come across any indication of such among the L, R, or Z mounts. So I'd expect it to be some time.
 

Antigen

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It's required. However, the way in which it's required depends on the software.
I ask this because actually i use Silkypix 9 Panasonic Version but if in future it will be become otadet and the producers made a new version like Silkypix 11... the 9 version it will be able to correct the lens made in the future?

This question is made only because i think that RAW + lens correction is a very usefull and powerfull tools and the fact that the MU43 lenses will be retrocompatible with old body and allow correction is very powerfull.

But... if the correction is made by an external software (like Silkypix or other)... the weak ring of the chain can be the software.

An example:

- i shot with a Olympus/Lumix 2010 MU43 camera + a 2019 lenses = camera embed into the RAW file the lens profile for correction
- i open the RAW file with the software included with the olympux/lumix camera (dated 2010)

It will be able to detect and translate and correct lens data correctly?

I know the power of the RAW file, but if it will become a "nightmare" where i need all the time a new software... oh my God!
 

archaeopteryx

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It will be able to detect and translate and correct lens data correctly?
@wjiang pretty much answered this already. For perspective, in Panasonic terms you're asking what would happen if somebody put a Panasonic-Leica 10-25 f/1.7 on a G10. Personally, I wouldn't particularly worry about it unless you can find a G10 that still works along with a copy of Silkypix 4 or whatever was bundled with it.

I think you're close to recognizing digital photography companies like to monetize photographers through software as well as hardware. Perhaps a good next step might be a look through the many threads where people complain about whatever raw developer it is they use not yet supporting whatever new body they just bought.
 

junkyardsparkle

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Partly because Panasonic and Olympus haven't made lens corrections an open standard, LibRaw based tools (darktable, RawTherapee, and quite a few commercial raw developers including some versions of Silkypix) usually attempt to work around the closed nature of the μ43 specification by matching the body and lens names in the EXIF to a lensfun profile.
Minor technical note: darktable isn't really LibRaw based anymore... the point still applies, though.
More about how @junkyardsparkle is holding that together almost singlehandedly for all of on a volunteer basis in this thread.
I hasten to point out that this hasn't been the case lately; I've been trying to maintain focus on the entropy in my more immediate world, and hopefully now that the project has moved fully to github, it will attract some fresh contributors.
Probably the simplest way to get answers is to pixel peep test images chosen to show distortion, vignetting, and chromatic aberration.
This is also a good way to simply get a sense for how much different lenses rely on this correction. It can vary from "a lot" (wide end of a compact zoom) to "almost nothing to correct" (I don't even use correction on the Oly 60mm macro).
I think you're close to recognizing digital photography companies like to monetize photographers through software as well as hardware. Perhaps a good next step might be a look through the many threads where people complain about whatever raw developer it is they use not yet supporting whatever new body they just bought.
Case in point being that the E-M1X support for darktable was added just after the latest 2.6.2, so it may not see a (non-beta) release until 3.0 sometime around the next solstice... :rolleyes:
 
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