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Thread: LCC Theory

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    Super Duper
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    LCC Theory

    I just finished reading an article Colin Page did for Phase One; part of it addressed lens cast corrections and how he went about it.

    When I first started thinking about LCC my first thoughts were that I only had to do an LCC once per lens with no movements; that was until I read the article. It now makes sense that you do an LCC per each movement and f/stop.

    I’m in the early stages of performing an LCC for various f/stops and movements for each of my lens for the RS 1000; here’s my thinking:

    f/11 centered
    f/11 centered 10mm left shift
    f/11 centered 10mm right shift, etc

    I plan on doing this at various f/stops and both 10mm and 5mm rise and fall and shifts then compile a library to use in C1.

    I’ve got a couple questions:

    I want to use this both on my studio computer as well as my laptop – the plan is to do the work on the studio computer then copy that library to the laptop. Where do I find the file in C1 that contains the LCC adjustments?

    Secondly, am I going about this the correct way? Am I missing something?

    Thanks in advance

    don

    Can't get the link to work corectly so here's the address http://www.phaseone.com/upload/90_colinpage.pdf
    Last edited by Don Libby; 22nd December 2008 at 13:22. Reason: link info
    Don Libby
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    Sr. Administrator Jack's Avatar
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    Re: LCC Theory

    Hi Don:

    As I understand it, the angle of light through the lens can also affect the cast, so my thinking is you need to do one LCC frame for each main composition...

    Cheers,
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

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    Re: LCC Theory

    Quote Originally Posted by Jack Flesher View Post
    Hi Don:

    As I understand it, the angle of light through the lens can also affect the cast, so my thinking is you need to do one LCC frame for each main composition...

    Cheers,
    Thanks Jack Im in the process of shooting at both a 5 and 10 mm movements (the ones I use the most) I figure a minimum of 9 shots per f/stop. Now what I need is to find where the LCC files are in C1 so that I can copy and past them onto my laptop.

    don
    Don Libby
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    Sr. Administrator Jack's Avatar
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    Re: LCC Theory

    Don, I think you are maybe missing my point: As the angle of light on the scene changes, the LCC profile changes (IIRC), so in effect there is not really any way to create them in advance for ALL possible lighting conditions. But for sure, having a standardized set if preferable to not having anything at all...
    Jack
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    Workshop Member lance_schad's Avatar
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    Re: LCC Theory

    Just be careful not to use too high of an aperture, just use the optimal one for each lens. Using too high of an aperture may lead to errors in creating the LCC at high apertures .

    Below is a clip from some Phase One correspondence:

    "LCC reference file has been shot on a high aperture where the amount of vignetting the lens is displaying degrade the LCC file. Open up the lens when creating a LCC reference file. Normally you have to open around 2 f-stop when crating a reference file, rather open then lens then do a longer exposure."

    I usually recommend that you create on for the optimal aperture for the particular lens.

    Your LCC's can be shared between your systems and are located in the /user/Library/Application Support/Phase One/Chroma Calibrations

    It is wise to use a naming convention similar to your example to keep track of them.

    Have a Happy Holiday Season everyone.
    Last edited by lance_schad; 22nd December 2008 at 16:02.
    LANCE SCHAD - Digital Transitions - Phase One,Mamiya | Leaf,Arca-Swiss,Cambo, Profoto
    direct/cell:610-496-5586 office:877-367-8537x224
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    Member Clawery's Avatar
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    Re: LCC Theory

    Don,

    Here are a few Knowledge Based Articles from Phase One. The first two links for PC users (since you are PC) and the last is for Mac users. The second PC link is specifically for stitched LCCs.

    Please let Doug or I know if you have any more questions. We would be glad to help.

    LCC - PC
    http://www.phaseone.com/HOME/Content...ite%20-%20Main

    LCC - PC (stitching)
    http://www.phaseone.com/home/Content...ite%20-%20Main

    LCC - Mac
    http://www.phaseone.com/HOME/Content...ite%20-%20Main

    Chris Lawery
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    Re: LCC Theory

    There are two basic theories on LCC workflow. The first is that the vast vast majority of color cast varies with lens and position of the back relative to the lens and therefore a library of images can be used to correct any given image to the point where no lens cast can be visible even in wide open areas of continuous tone.

    The second theory is that aperture and ambient light do have some effect on lens cast and therefore you should create a new LCC for every single shot.

    I tend to lean towards the top theory as, based on our practical experimentation, an LCC based on the combination of lens and position (e.g. "rise 10mm") is enough to correct any visible lens cast. In this case I mean "visible" as in if I myself look at the final product I am unable to notice any cast even on thorough inspection. Now technically speaking there may well be some cast (e.g. RGB=230,230,231 for a "gray") but I like to create workflows around practice and not theory; if I, as an expert viewer can't see it even when I'm looking close, then nobody else can see it and therefore for my purposes it doesn't exist.

    If you agree with my basic philosophy (and I would not think any less of someone if they did not then you need not worry at all about ambient light or aperture (except, as Lance points out that you should not create the LCC using a fully-wide-open, or fully-closed-down aperture) and only worry about lens and position.

    However, if you create a library that implies that you will record and maintain record of which lens and what amount of rise/shift you used on every shot you take. This may work for some people depending on the volume of shooting you do, and if you forgot to record this on one or two shots it wouldn't be the end of the world since you could guess and check (most landscape is going to be either -10, -5, 5, 10, 15, or 20mm of rise/fall and you're probably going to remember if it was a "little" or "a lot" so you'll only have to test two or three LCCs). However, another workflow, and the one I suggest, is simply to shoot one before every shot. That way when you get home every shot comes with a idiot-proof LCC to apply.

    It all sounds pretty tedious, but once it's in your workflow you hardly notice anymore; at least in my experience.

    Finally, as pointed out in the KB articles Chris linked to you can find the LCCs (on a PC with C1 4.X) in "C:\Documents and Settings\Your User Name\Local Settings\Application Data\CaptureOne\LCC\". One note: copy the LCCs to the target computer BEFORE launching Capture One to view the folder of related images. That way Capture One finds and uses the LCCs, preventing you from having to reapply them.

    Doug Peterson, Head of Technical Services
    Capture Integration, Phase One & Canon Dealer | Personal Portfolio

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    Re: LCC Theory

    I want to express my thanks to all who’ve responded.

    I’ve been busy lately slowly building a library knowing that I will still have to occasionally shoot an LCC on site.

    Thanks again

    don
    Don Libby
    Iron Creek Photography
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    Re: LCC Theory

    I shoot one for each and every shot. I do this for a few reasons. Sometimes I have someone else doing my post work and its too much to coordinate with him about what lens, what f stop what shift etc. Also when I need to go back and reprocess something I'd have to find the lens details again because i find that sometimes the software does not retain the LCC settings between working sessions. So shooting an LCC with each view keeps the LCC right there next to the captures.

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