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NEX6 AWB issue with legacy lenses

Discussion in 'Sony Alpha E-Mount Cameras' started by WT21, Aug 25, 2014.

  1. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011
    I was shooting today to test some sharpness between my NEX 55-210 and some legacy lenses I acquired -- SuperTak135 and MD100 -- when I noticed some odd AWB issue.

    It seems when shooting with the 55-210, the AWB seems to understand when to move to "daylight" but it doesn't so that with the legacy lenses. I have many examples, but here are 3 below.

    The first is the 55-210 with AWB on
    The second is the MD with AWB on
    The third is the MD with WB set to daylight (just to make sure it's not a lens color cast issue)

    It seems to me that the WB daylight on the MD looks just like the AWB on the 55-210, but in my tests so far, I cannot get the NEX6 to AWB correctly on the MD (it does fine in the shade -- I haven't tested incandescent yet, but I guess I should.). FWIW, the scene was early AM, and the real color is much closer to the first shot with the 55-210, than the other two.

    I want to shoot jpg, so this is a pain for me. The camera did the same thing with the SuperTak, but the SuperTak has an evident amber color cast, so I didn't think it was worth showing that.

    Anyone see anything similar to this issue?

    20140825-DSC07319.
    20140825-DSC07322.
    20140825-DSC07324.
     
  2. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    I guess the color rendering has a little to do with the different results. But as AWB is the main thing to blame here, just try switching to one of the preset modes. For daylight, either choose "Sun" or "Cloudy" or whatever they're called in the english menu. You should be fine without changing it during the whole shoot.
     
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  3. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011
    I discovered this when shooting outdoors -- where I might be shooting in shade one minute (under a tree, e.g.), or in daylight the next. Shade was fine, but daylight was rendered too cold. I was hoping my 21st century camera would AWB for me :(
     
  4. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    Well, the WB is not totally off either. It looks close enough in all three shots, although arguably it looks best in the first shot. When going from shade to sun frequently, just try the outdoor WB presets available in the camera. I'm pretty sure there's one which works in both situations pretty well.
     
  5. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011
    #1 and #3 are very close, and essentially the same. But it's #2 that's the issue -- that's the AWB setting. I would prefer to avoid setting my WB each time

    But maybe I'm misunderstanding what you are saying.

    I see a WB setting for daylight, shade and cloudy, but I can't see one labaled "outdoor"

    Do you mean a WB setting or a SCN mode (or something else)?
     
  6. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    Yes, because obviously Sony thinks you need three different settings. When you're out next time just try all three in shade and sunlight, at least one of them should yield good results for both situations.

    I really don't know why the AWB gets confused when using the MD lens. Can you check what the color temperature was on the three images you shared here? You should be able to find that information in the EXIF data. Maybe we can figure out the reason for it that way.
     
  7. shaolin95

    shaolin95 TalkEmount Top Veteran

    942
    Jul 3, 2013
    I actually have seen this with any E lens I tried compared to my legacy lenses no matter if it was Rokkor or Canon, the rendering of the legacy ones will be very similar and totally different from the E ones just as your images.
     
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  8. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011
    I have a mac with Lightroom and CameraInfo. Neither show a color temp in the EXIF. These are all jpg OOC shots. I could reshoot with RAW, to see what the camera thinks it's seeing.
     
  9. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011
    I think I know the answer (RAW or WB manual), but what do you do to control it?
     
  10. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    If its actually the lens' color rendering - and this well may be as the WB seems right on all three images - then there are a few things you could do to get results with legacy lenses which are similar to what you get with E-mount lenses.

    1. Manually choose a warmer color temperature in-camera.

    2. Shoot RAW and change the color temperature when post processing your images.

    3. Change the color of your JPEG images (this, however, will loose some color information as opposed to option 2).
     
  11. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    A good thread about a good subject with good explanations / suggested alternatives....thanks !

    I have no e-lenses to compare all my Canon FDn lenses to but have always thought my photos were a bit cooler / darker than they should be right out of the camera. The NEX-7 default setting was for AWB, but switching from AWB to Daylight just now, makes colors much more natural looking.

    These are just no-nothing grab shot photos out the back door for test purposes:
    First photo with "AWB" setting shows the ground dark, almost gray...but its actually covered with brown pine needles.
    Second photo with "Daylight" setting shows the pine needles more natural color brown.

    Canon FDn 80-200/4.0-L, NEX-7, Manual Mode, Spot Metering, ISO200, 1/200, F4.0

    AUTO WHITE BALANCE




    DAYLIGHT SETTING

     
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  12. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011
    I wonder why it does this. Is it non-chipped lenses just default to a certain WB. AWB only works with lenses that report who they are?

    I'm going to have to run some experiments.
     
  13. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    No, AWB works with any lens. Heck, it even works if you don't attach a lens at all.

    It's just that many legacy lenses aren't fully optimized for color photography (depending on how old they are), nor are they optimized for the more angle sensitive digital sensors or their sensor stack. It's clear that they can't deliver the same colors as modern lenses. Still, looking at all the examples here, the white balance never was off, just the colors were a little different. If you want the colors of your legacy lens to match that of your modern lens, well, then a little post processing will be necessary.
     
  14. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011

    I shot 4 RAWs of a daylight scene outside. The temp and tint in LR reports as:
    1. MD Lens, AWB -- 4300, +21
    2. MD Lens, Sunny WB -- 5150, +5
    3. SEL, AWB -- 4850, +4
    4. SEL, Sunny WB -- 5150, +5

    So, the AWB is, indeed, being tricked in some way.

    I would have thought if the lens was tinted, then either a) the AWB would correct it back to neutral, and/or, b) if you forced the temp and tint to the same settings (i.e. 5150 and +5) by using a set WB, then the colors should be different, given the lens tint, rather than the same. But they look the same when set to the same WB.

    20140825-DSC07332.

    20140825-DSC07333.

    20140825-DSC07334.

    20140825-DSC07335.
     
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  15. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
    Those last photos certainly seem to support your conclusions...bottom line, AWB seems to produce darker, cooler colors.

    This thread has been a real eye-opener...and very timely too. There's been a lot for me to get up to speed on with my NEX-7's full range of capabilities / options / adjustments...and I haven't gotten into this area at all yet...just assumed / never questioned the default feature of Auto White Balance was on the money and a preferred all around choice.

    But now that doesn't seem to be the case...just from these few simple tests it appears "AWB" has been having an undesirable influence on the color / brightness of my photos. And if "white balance" is still good using the "Daylight" setting anyway, makes me wonder what AWB it's really supposed to do in the first place...unless it's really just a preset of some sort of average WB.

    Now that I'm aware of it, since most of my shooting is outdoors in natural light, until further notice I'll now use "Daylight" as my default setting, and also experiment with the "Cloudy" setting as conditions dictate...see if I can detect a trend of improvement across my photos.
     
  16. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011
    FYI -- I'm reading this now http://www.cambridgeincolour.com/tutorials/white-balance.htm in case you are interested ;)
     
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  17. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    Austria
    Auto white balance is an absolutely necessary feature in some situations. For example, when shooting a concert where light changes by the second and is only available at a very restricted wavelength variety which means you can't correct WB in post, AWB is a must. Daylight is arguably a situation where manual WB might yield better results.

    Still, for those situations, there's a thing called RAW. And you know, that thing allows you to change the white balance in post - at least when you shoot in anything but pure darkness.
     
  18. roundball

    roundball TalkEmount Hall of Famer

    Oct 8, 2013
    USA
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  19. xXx1

    xXx1 TalkEmount All-Pro

    Jan 15, 2013
    Color temperature is about lightning and not about lens color rendering. If a light source resembles black body radiation (for example sun is black body ;) ) it has got it's peak wavelength at certain position and that position depends about temperature of object.

    see:
    http://en.wikipedia.org/wiki/Black-body_radiation

    Now image may have perfect white balance (that is the peak wavelength is in wanted position) but heavy color cast if distribution of wavelengths differs from optimal. That is due the fact that lenses aren't perfectly transparent and that is because materials and construction of lenses. For example fresnel reflection loss is dependent about material and wavelength. Multicoatings affect great deal color rendering of lenses.

    In practice you choose lenses whose color rendering you like or correct it in post processing. Better brands usually have (or maybe had) better color rendering. I suppose that lens design is much easier in that respect too and secrets of multicoatings have leaked from top producers (I think that Zeiss and Pentax were leaders in this in old days), Multicoating is (or was) pretty complex subject.
     
  20. WT21

    WT21 TalkEmount Top Veteran

    611
    Aug 7, 2011
    I am not sure how that explains that the NEXes with legacy lenses mentioned here (so far mentioned: Takumar, MD, FD) causes the AWB to shift to a much cooler than expected WB. I was looking through my old m43 pics, having over 300 shots on legacy lenses, and more than half of those shot in daylight, yet with color temps for WB in the 5200 range, not the 4300 range. At the end of the day, it is what it is, but it sure is curious, IMO.
     
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