Advice on white-balancing

Discussion in 'Badminton Photography' started by Gollum, Jul 29, 2010.

  1. Gollum

    Gollum Regular Member

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    I've recently bought a new camcorder (Panasonic HDC-SD700), to improve the quality of Badminton Bible videos.

    I'm trying to work out the best settings for recording videos. I've used the low-light preset and the auto mode, and I've also tried manually setting the white balance using a sheet of paper. The auto and low-light modes look identical, but the manual version is quite different.

    Which should I use? Or should I do something different?

    The manual one appears to be more "accurate", as it shows white colours as true white. In the auto/low-light mode, whites are actually a light pinkish colour.

    One the other hand, the auto/low-light version has a warmer tone, whereas the manual one could feel a bit cold.

    Any advice? These are greatly cut-down images, by the way. I can supply the originals if anyone wants them (2.6 Mb), or even the videos (~250 Mb and need a fast PC to play).
     

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  2. taneepak

    taneepak Regular Member

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    The manual WB is better but it is good only for the same hall. In another hall you will have to do it all over again because of different colour temperatures of the lighting.
     
  3. Gollum

    Gollum Regular Member

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    Thanks, it's good to get your feedback. :) Assuming I go with the manual white balance, I would re-balance every time.
     
  4. taneepak

    taneepak Regular Member

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    Yes, you need to re-balance only when the lighting changes, which would be the case if you change the venue. Don't be fooled by similar lighting fixtures in different venues because they look the same-they are not. Only by using a manual WB are you assured of the correct colour temperature.
    Using a special photographic grey card instead of a white sheet of paper would be better to get a wider dynamic range. But a white paper will do as it is the most convenient.
     
  5. Gollum

    Gollum Regular Member

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    I was thinking about getting one of those, but I'm not sure about using a white vs. grey card (they often come together, but I still have to choose which one to use).

    Would low-light conditions favour a white card instead of grey (because the grey may end up rather dark)? Or am I better using a grey card in all conditions?

    (The hall is actually quite dark -- it's just a good camera.)
     
  6. kwun

    kwun Administrator

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    if you are completely picky about it, i suggest get proper gray card that are designed for WB calibration.

    some (actually, most) gray card designed for exposure but they are not guarantee to be neutral gray. they are just 18% in overall darkness, and not balanced to be neutral.
     
  7. kwun

    kwun Administrator

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    another point.

    how your orient the gray card when you take the reading also matters. in a gym like the one you have in the photo, there are vastly contrasting colors from wall and floor, if you point the gray card towards the wall, it will be "greener" due to the reflection from the wall. if you point it towards the floor, it will be yellow/warmer for the same reason.

    the best is to place it the same orientation as the subject, which in this case, will be align it with the face of the person.

    i used to just WB by facing the card to the light, and everyone face ended up green from the reflection of the badminton green mat.
     
  8. RSLvictorSOTX

    RSLvictorSOTX Regular Member

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    A neat trick would be to point and focus your camera at the whitest tram lines there is (in whichever hall or arena in any lighting condition...) for a second, press halfway, hold, aim and release to shoot your subject/object.
     
    #8 RSLvictorSOTX, Jul 29, 2010
    Last edited: Jul 29, 2010
  9. justinwyyau

    justinwyyau Regular Member

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    In my humble opinion, I find the auto white balance/low light setting more pleasing to the eye as compared to the manual white balance setting. And big up's for your website :)

    Justin.
     
  10. visor

    visor Regular Member

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    ^^Second that. A tinge towards reddish is always more pleasing to the eye than towards greenish.
     
  11. Gollum

    Gollum Regular Member

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    That's exactly why I find this decision difficult: the manual white balance is more "correct" -- in the sense that it more accurately represents how the hall would look under neutral lighting -- but the auto/low-light feels warmer.

    I think the auto/low-light better represents how the hall does look under the actual lighting conditions. The human brain is doing its own white-balancing, of course!

    It's a tricky decision. I could still go either way, but at the moment I'm inclined towards manual white-balance.
     
    #11 Gollum, Jul 30, 2010
    Last edited: Jul 30, 2010
  12. justinwyyau

    justinwyyau Regular Member

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    True, it may be more correct but in my opinion, the auto white balance/low light version looks more pleasing and 'natural' to the viewer viewing your videos over the Internet. I think achieving that is more important than trying to replicate how true a hall looks life in real life.

    Either way, whichever white balance you decide on is ultimately on you, but it still won't distract away from the quality of the content that the video is trying to deliver :)

    Just my thoughts,

    Justin.

     
  13. ctjcad

    ctjcad Regular Member

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    okay, let's set up a poll to help Gollum with his difficult decision!..:cool:
     
    #13 ctjcad, Jul 30, 2010
    Last edited: Jul 30, 2010
  14. Gollum

    Gollum Regular Member

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    Ooh, yes please! :)

    Some good news: I think I can provide full 1080p HD video. I've tested it at a 5 Mbps bitrate, and it looks mostly free of compression artefacts. Obviously there's going to be some loss of quality due to the extreme compression, but I think I get away with it because my videos use mainly static backgrounds (no camera movement), which compress very efficiently.

    That's at 30 frames per second; the source footage is 50 fps. Not sure whether there's any point trying for 50 fps production, but it does give me some more frames for using in slo-mo shots.

    You'll need a fairly fast computer to decode that, however. It uses about 30% of my monster i5-750 CPU, distributed across all four cores. :eek: No chance on a Mac...

    I should probably get a bigger monitor, so I can actually see the full-size video. :rolleyes:
     
    #14 Gollum, Jul 30, 2010
    Last edited: Jul 30, 2010
  15. taneepak

    taneepak Regular Member

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    The auto WB almost never gets it right inside a badminton hall. Hence the need to WB with either a white or grey card. What this means is that you set your WB manually by focussing it on the white or grey card with the latter under the same lighting as the players. But white cards or paper all have various degrees of whiteness. A photographic 18% grey card is more accurate.
    Suggest you get one of those photographic cards, the ones having white on one side and 18% reflectance on the other side, and then test them. Both will be pretty close, but I think the grey will be better if the scene is contrasty.
     
  16. Gollum

    Gollum Regular Member

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    Thanks, I think that's probably what I'll do. :)
     
  17. Mini Me

    Mini Me Member

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    what codec did you use? it sounds like you haven't enabled gpu-assisted decoding. the previous generation core2 duo can decode 1080p AVC/VC1-encoded files with less than 10% cpu usage if you have gpu assistance.
     
  18. Gollum

    Gollum Regular Member

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    I'm using H.264 in an F4V container.

    You have to remember that video is much more compressed for distribution on the web. H.264 is especially efficient, but it comes with a price: the CPU has to do more work decoding the stream.

    It's also worth remembering that when people talk about "1080p", they mostly mean 1080i -- at least when shot from a consumer camcorder. 1080i has effectively half the vertical resolution of 1080p.

    When I play the raw .mts files from the camera, my CPU usage is about 5%, and the system is actively underclocking itself to save power. Those files are full 1080p at 50 frames per second (and they look great :D). Not even Blu-ray can store this "1080 50p" footage.

    To put it in perspective, look at the bitrates. I'm compressing the video into 5 Mbps, but the original bitrate was 28 Mbps.
     
    #18 Gollum, Jul 30, 2010
    Last edited: Jul 30, 2010
  19. Gollum

    Gollum Regular Member

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    I tried applying some colour-correction to take away the slight green tinge on the manual version. Just dialling down the midtone green by 22% got me this:

    tweaked-from-manual.jpg
    manual-white-balance.jpg
    auto-white-balance.jpg

    Personally, I think the tweaked version is best. In particular, the flesh tones look more natural: it gives me neither a glorious tan (low light) nor sickly green zombie-skin (manual). ;) Opinions?
     
    #19 Gollum, Jul 31, 2010
    Last edited: Jul 31, 2010
  20. visor

    visor Regular Member

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    ^^ Very nice balance! :thumbsup
     

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