Page 1 of 3 123 LastLast
Results 1 to 10 of 21

Thread: White Balance - many questions

  1. #1
    Join Date
    Feb 2006
    Location
    Surrey, UK
    Posts
    10,847
    Blog Entries
    1

    Default White Balance - many questions

    Well, I thought I knew this stuff and it was simple but ...

    (You can ignore all this preamble unless uyou think it's relevant)

    Tomorrow we shoot the first scene of a film that's been in the pipeline for a while. The scene is being shot in a pub in the daytime. Perhaps unimaginitively we have two blokes sitting opposite each other at a table. The shot will comprise a master and opposing OTS.

    There is a window a a few paces away begind one of the men. Pubs being what they are nowadays the window has an LCD TV screen immediately in front of it, thus reducing the vast majority of the light coming in although there is clearly some.

    Not wishing to leave too much to chance, we ran a technical rehearsal on Monday. Obviously we set up so the Window and its ugly TV screen were not on the frame. We used the wall mounted tungsten lights (again kept out of shot to avoid burnt out bits) a few LED 160s with tungsten filters, and a relector (this seemed to work better than direct light - much as you'd expect).

    When I came to examine the footage, the shots of the man facing the window looked pretty good (I'd expected this to be the problematic shot as he was the one lit by more of a mix of tungsten/LED and natural(. The guy shot from the opposing direction though looked decidedly green. I improved it a bit in post and can probably do better, but I'd rather get it right from the off.

    OK, I thought, that's because the camera op just used the in-built auto white balance (Camera is a Sony FX1 - the consumer version of the Z1). What we need to do is set the white balance manually each time we reposition the camera.

    So, off I trotted to his place to demonstrate. And here's where I now feel I've lost the plot.

    (Preamble ends)

    We managed a similar but more extreme setup in his house. One end of the room joined on to a conservatory so there was plenty of natural light coming in from there. We lit the room with tungsten.

    I stood at the conservatory end of the room (position "A") and performed a WB (in the time honoured tradition of holding a piece of white A4 in front of his face) Lets call that WB setting X. The resultant looked great. Keeping the same WB setting I moved to the other end of the room (position "B") the image was still pretty good (although he was not lit well enough - as I said this was more extreme than in the pub)

    I then set the WB again from this new position (Position "B" WB setting "Y") The resultant image was decidely cool in colour and certainly wouldn't match the first image. For example, he was alongside a palish lemon coloured wall. From "position A" using WB X the wall was clearly pale lemon. From position B using WB X the wall was still clearly pale lemon - though much paler as one might expect with external light reflecting off the wal towatrds the camera - ie it was quite natural.

    Using WB Y, the lemon wall looked, if anything a very slightly bluey white from position B, and only barely yellow from position A.

    So these tests would suggest to me that when I come to shoot tomorrow, once we've set the WB and got an image we like, we should leave it well alone even though we are moving to different positions within that environment. Is this correct?

    What I would really like to understand though is why, when setting a white balance from position B above, were the results so dreadful? (I performed the operation several times to double/triple check, and the camera never complained that it was struggling to get a good WB reading.
    Tim

  2. #2

    Default

    Hello Tim

    I used to film weddings in churches, halls, and reception venues and each time moving to a different position I would reset the White Balance every time in variable light conditions to make sure, using the back of a white business card held at arms length in front of the camera lens . The results of which I was pleased with. I know its a pain but dont asume what you set up today will be the same tomorrow it may not be. All to often we trust the camera will see as we do. As fantastic as technology is now, its not a patch on what the human brain can do automatically. which we all take for granted.

  3. #3
    Join Date
    Mar 2005
    Posts
    4,192
    Blog Entries
    2

    Default

    In drama, a discipline which it's worth trying to get to use is to always (when possible) work with pre-sets. In other words, decide which camera setting you're going to use (tungsten or daylight) then try and filter your lights to the camera, rather than the other way around. Otherwise it's a bit like one of those games in the christmas cracker where you have to get small ball bearings into holes. Just as you think you've got it, one of the balls drops out. You white balance for one light then another influences the shadows and another reflects off the... etc. etc.

    Firstly, try and get the telly switched off. It is adding all sorts of colours into the mix.

    At the risk of nagging Timothy... those LED 160s!!! Cheap chinese eh? well, they are very, very green. When you try to white balance this out you will end up causing your other light sources to go way out. If you've got time, PM me your address and I'll bung some minus green gels to you, they should be there before the weekend. The magenta plastic which comes with the lights is almost useless and causes the red/blue balance to go way out.

    One thing to remember with the white balance is that the camera will almost always be white balanced to the main light, the key. Yet the camera (and our eyes) are more sensitive to changes in colours in the shadows and mid-tones.

    Edit: If it's a two-camera shoot with two different makes of camera then... Get both cameras lined up on a white card, filling the entire frame. Either it should be lit just by tungsten or just by daylight, depending how you're going to work. White balance both the cameras and then leave them alone. Adjust the lights to the cameras as before.
    It sounds like that lemon wall influenced your white balances. It is a whacking great reflector, after all. So when doing a WB on the white card (not paper, paper can let light through from the back) make sure that you're not getting any fill from the lemon walls or suchlike. But, better still, use the pre-set.
    Last edited by Rembrandt Rob; 07-25-2012 at 07:33 PM.

  4. #4

    Default

    I'd go with RR. Use a preset on both cams. At least it's locked and you could if it looks iffy adjust to suit in the edit. I've WB'd in all sorts of mixed light locations and had to settle for what looks 'right' and not strictly 3200k or 5600k. Pre-sets are pretty good and they do spend 1,000s getting them set nice n pretty in the factory.
    My opinions are just that . . . Mine. It's not personal, but is based on my emotional and professional reaction to requested critique. If you choose to ignore constructive comments, I'll just assume you're a vanity poster and not posting to improve your filming and editing skills.

    Ex A.P.V Videomaker of the year - Ex M.M. IOV Come join my EXclusive club

  5. #5

    Default

    You could do what Rob says or just blag it, when asked why that bloke looks green, just reoly he's an alien.

  6. #6
    Join Date
    Feb 2006
    Location
    Surrey, UK
    Posts
    10,847
    Blog Entries
    1

    Default

    Thanks all for your swift replies. Thanks also for your offer Rob, but I'm shooting tomorrow - arghhh! That is unless we abandon it because my father in law is seriously ill and I might be required elsewhere.

    Only one cam.

    I'll go with a preset (or at least the same WB from all positions). The TV is not on! It's just acting in this case as a barrier to the natural light.

    Following up on a couple of points:

    Lemon Walls: The sheet of white A4 was pointing away from the lemon walls and held up in front of the director's face. The walls opposite were covered with a (old wood) bookcase and an (old wood) door so I don't believe and direct reflection or colour seeping through the translucent paper (which was actually 14 sheets of script!). However what you say makes sense and I wonder if the lemon walls reflected off the white ceiling then back onto the white might have had an impact.

    LED 160s (in fact they might have been 96s). Didn't you recommend them once? There aren't the very cheap ones by the way and neither are they mine - but a member got carried away and bought them (a four pack bundle for around 230) We didn't use mgenta gels but amber/yellowish ones. And the light wasn;t direct. It was off a gold reflector.

    What's strange is when we added them to what ended up as the "good" shot (the actor facing the half covered natural light) they made teh skin tones much warmer.

    I knew full well we were asking for trouble mixing tungsten/LED with outside light, but we have no choice and have to work out the best solution we can.

    Out of interest, how do pros film inside whern there's natural light coming in as well. Replace the tungstens with daylight coloured lamps? But then how do they still manage the nice warm tones that tungstens give?


    EDIT: I get bloody frustrated that I have only 10% of the knowledge required and 2% of the money required to make a film I'd be maybe 80% satisfied with. However, I'm sure that if I was just given everything I needed to do a good job I'd not learn or understand nearly as much as by trying to get by using two washing bottle tops and sticky back plastic. So I really appreciate all your input.
    Last edited by TimStannard; 07-25-2012 at 10:03 PM.
    Tim

  7. #7
    Join Date
    May 2012
    Location
    So Paulo - Brazil
    Posts
    811

    Default

    Except for Mr. Cameron filming AVATAR 2, everybody will always have just 2% of what is needed or wanted for a project.... And remember that your 10% of knowledge is about 53435532 times more than mine, and Im quite happy that my 10% is around 25312 times more than the world average!!!

    Wish I could help with something brilliant about the WB in your particular situation/shot, but all I can do now is read my camera manual once more and try to understand something new..... When in doubt, put in AUTO and blame the camera later!!!

    Have fun at the scene!

  8. #8
    Join Date
    Mar 2005
    Posts
    4,192
    Blog Entries
    2

    Default

    What I said about LEDs was... Only the most expensive (a couple of grand) LEDs are anything near accurate and there is no real difference between the 30 LED160s and the 200 Litepanels, so you might as well go for the cheapo copies in this case. Also that the cheap LEDs are great when working outdoors, at night away from a power source providing that you get rid of at least a little of their green spike.

    The gold reflector seems to be the magic ingredient. As well as softening the light it's taking out a lot of the blue/green end of the spectrum. Good idea.

    It seems like you've tamed the LEDs. Rembrandt Rob's Golden Rule "If it looks right, it is right, if it looks wrong, it is wrong".

    If you look on a "real" location shoot, you'll see loads of stuff made with two washing bottle tops and sticky-back plastic, or coat-hangers and gel, or DIY materials. Most "Gaffers" and "Best Boys" will be adept at constructing all sorts of weird and wonderful contraptions.

    As for your 10% of the knowledge, don't put yourself down Tim. The real skill is seeing that things don't look right, you'd be surprised how many people don't "see" that a shot isn't working. in fact, every day we see videos here on VideoForums where the videographer didn't "see" what isn't quite up to scratch. That obsession with getting things "right" doesn't change either. It's just that the longer you film, the more exacting you become. I'm now doing more work as a "Lighting Director" than as a cameraman now that just about every media studies graduate who has used a D5 is calling himself a "Director of Photography" but has to call in an LD to "help out" with the lighting. Most of them don't have the knowledge that you do, they just think they do, so don't beat yourself up!

    How do pros film indoors..? It all depends on the budget and how well you planned. Either put orange gel across the windows, making daylight into tungsten or use larger lights balanced for daylight. Inside you can use discharge sources (which are like tungsten units but use an arc of light rather than a filament and give a daylight coloured light) or daylight fluorescent tubes. Fine tuning and adding a bit of warmth is done by adding gels. You don't have to buy a whole roll, you can buy meter squares quite cheaply. When using tungsten, a blue gel (CTB 201) will filter out a lot of the red content and bring it towards daylight but... you lose a lot of light in the process. I tend to only half balance tungsten lights (using a half blue, rather than a full blue) which still leaves some warmth in the light for the skin tones.

    As for the 2% of the budget... It has been said that the answer to the question "How many lights does an LD need to get a scene perfect?" is "One more than he has available."
    Last edited by Rembrandt Rob; 07-26-2012 at 08:57 AM.

  9. #9
    Join Date
    Feb 2006
    Location
    Surrey, UK
    Posts
    10,847
    Blog Entries
    1

    Default

    Thanks, Rob, for your further explanations, additional tips, and your words of encouragement. You're right about the obsession with getting it "right".

    Whilst I accept we're never going to reach perfection, and it's even harder to get there on a budget, there's no point it aiming for anything less.
    Tim

  10. #10

    Default

    It's always a compromise trying to get it right. Fool the scene with gels and lights or just a good reflector to make use of available light. Time, budgets and equipment can sometimes overpower the simple scene were trying to film.
    As an example I started a wedding edit yesterday and on the day the church interior, lit mainly by tungsten and outside light, had these very large, pink plastered walls.
    My user pre-sets that are normally 3200 & 5600 just didn't 'get it' - spur of the moment I threw a 'grubby' white hankie over the lens, zoomed in and locked my WB on the wall and they registered 4200k - and it looked perfect. The film looks perfect in the edit too, but had I gone for my usual presets, I know the walls would have leapt out 'greyish' in the edit.
    Technical perfection sometimes just doesn't look right, so we all just have to trust our instincts on 'the look's
    My opinions are just that . . . Mine. It's not personal, but is based on my emotional and professional reaction to requested critique. If you choose to ignore constructive comments, I'll just assume you're a vanity poster and not posting to improve your filming and editing skills.

    Ex A.P.V Videomaker of the year - Ex M.M. IOV Come join my EXclusive club

Page 1 of 3 123 LastLast

Similar Threads

  1. Replies: 12
    Last Post: 03-14-2012, 01:43 PM
  2. White Balance Theory
    By PinkFloydEffect in forum Technology advice and tips
    Replies: 32
    Last Post: 07-02-2011, 07:19 AM
  3. White balance problems
    By Treval in forum Hardware Problems
    Replies: 7
    Last Post: 03-13-2009, 02:24 PM
  4. White Balance, Reflection, Etc.
    By falieson in forum Adobe Premiere, Premiere Elements, and After Effects
    Replies: 4
    Last Post: 04-19-2008, 05:05 PM
  5. White balance
    By Mark W in forum Technology advice and tips
    Replies: 3
    Last Post: 08-01-2007, 08:05 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •