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Thread: D-lux4 (LX3), Raw Files and Lens Correction (c1 vs Raw Dev)

  1. #1
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    D-lux4 (LX3), Raw Files and Lens Correction (c1 vs Raw Dev)

    HI There
    I have Amin to thank for getting around to looking at this, which probably also relates to the G1 (I might have a look at that later on).

    I think most of us have realised that there is lens correction applied to the lovely new leica 24-60 summicron lens on these two cameras. I had not had a chance to look at the full implications of this until Amin pointed me in the right direction.

    I had been using Capture one to develop the D-lux4 RAW files with some success, this automatically applies the lens correction. Here are some comparisons (apologies for the horrid photo)

    This is the full image (in each case the capture one shot is first)

    Here is a centre crop

    and this is one from the corner

    In each case the file has a little sharpening applied after conversion.

    It would seem like there is no such thing as a free lunch!

    I have to say, I'm not very happy about the concept of designing lenses with the express intention of correcting distortion in post processing - it clearly has an effect on detail, and very much locks one in to the raw converter connected with the camera.

    What do you think?

    Just this guy you know

  2. #2
    Senior Member Amin's Avatar
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    Re: D-lux4 (LX3), Raw Files and Lens Correction (c1 vs Raw Dev)

    There are two sides to this. On the one hand, we can say that the Panasonic lens designers took the easy route and simply relied on the software to fix their lens ills. On the other hand, there is a reason no one has even put a wide zoom this fast in a lens as compact as the LX3/D-LUX 4. I tend to think of things in that respect. They're not using software fixes to accomplish what was previously done with optics; they're using software fixes to accomplish what has never been possible before: an f/2-2.8 wide zoom in a pocketable camera (LX3/D-LUX 4); amazingly compact megazooms with great edge to edge performance and low distortion (FZ18, FZ28). I don't mind them implementing software correction for lens flaws, so long as it doesn't make the optical design folks lazy.

    What I don't like is that Panasonic encouraged the major 3rd party RAW developers to implement a mandatory lens correction. Even worse, the Adobe DNG converter bakes these changes when converting to DNG. As you have shown, the D-LUX lens distortion is pretty severe; however, it really depends on the shot whether it needs to be corrected, and if so, whether it needs to be corrected completely.

    Btw, Jono, in Raw Developer try disabling noise reduction and implementing the Richardson-Lucy method under sharpening.

  3. #3

    Re: D-lux4 (LX3), Raw Files and Lens Correction (c1 vs Raw Dev)

    Surely it also means that leica now allows itself to produce dreadful lenses and are not to be trusted anymore even to make the coffee.
    Last edited by nei1; 19th January 2009 at 10:08. Reason: changed ending

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    Re: D-lux4 (LX3), Raw Files and Lens Correction (c1 vs Raw Dev)

    Hmm, true, I am not in total agreement in making lens that require correction afterwards via software or internal Venus iv software in JPG.

    But I suspect there may be downsides if Leica/Panasonic did not do these software corrections. Firstly, I do not think the optic would have been quite as fast, ie f2.0-f2.8, as the lens probably would have needed additional corrective lens inside to compensate for distortion, and hence less light getting through the lens and possible a larger heavier lens design. Alternatively, the cam may not have been able to achieve such wide angles in such a tiny pocket cam and with slower f-stop just to get more precise image. Also remember the lens is a zoom lens, which also attributes to more problems, as the lens has to cope with more than one focal length.

    Ideally, since Leica makes summicron lens as primes in both M, and R, they really should have made the D-Lux 4 like the GRD series Ricohs, and put just a fixed focal length in to get higher quality results without correction.

    In saying that all this software correction undoubtedly will reduce the IQ of the D-lux4 slightly, ie, less colors after CA correction, and less detail after distortion correction, but at least we get a usable image, and we are able to capture it easier thx to 24mm wide, and fast f2.0 lens.

    Anyway in some circumstances, I would say we got a bonus focal length lens out of using RAW, as we get a somewhat fish eye representation of what we see, plus a slightly wider angle than what is even specified.


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