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Old October 14th, 2009, 11:05 PM   #1
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EX1 misreading Kino Flo color temp

Hi all,
I have both EX1 and Sony F900R cameras and I've noticed a peculiar issue with the EX1 and my Kino Flo Diva lights.

The F900R reads (white balance) the 3200K bulbs as 3200K without problems, but the EX1 reads the same bulbs as 4500K. If I put CTO 1/2 or 1/4 on the fixture in front of the bulbs I can get close to the correct reading, but this solution is just for testing reasons not for actual production.

So I am wondering if this problem with the EX1 has been experienced by others and if so, how is it fixed? Also, is this perhaps related to the IR issue discussed much here and if so which one of the recommended IR filters for EX1/3 is now most recommended - B&W, Tiffen or Schneider?

BTW, the Kino Flo's have 1/4 +green on them to remove the endemic magenta hue of the Kino Flo 3200K bulbs but even removing that gel doesn't change this Kelvin misreading. Also, this is an interior/3200K only problem - 5600K hmi's outside read fine on the EX1.

Any thoughts or suggestions will be appreciated.
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Old October 15th, 2009, 12:44 AM   #2
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I know this isn't an answer to your question but couldn't you just dial the white balance to 3200k through the picture profile?
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Old October 15th, 2009, 01:08 AM   #3
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Don't get knotted up over what the white balance numbers read out in your EX-1 or any camera. Its not a critically designed circuit. The question is how do your pictures look. If the 2 cameras respond to the light in a similar way forget about the numbers. Should have nothing to do with IR BTW.
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Old October 15th, 2009, 11:14 AM   #4
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Quote:
Originally Posted by Nathan Hudson View Post
I know this isn't an answer to your question but couldn't you just dial the white balance to 3200k through the picture profile?
That's not such a bad idea, I'll try that out. As far as the white balance circuit being somewhat inaccurate, I would buy into that except the camera has no trouble reading actual tungsten lights like Arri and Mole Richardson's at the correct 3200K, just the Kino Flo 3200K flourescent bulbs. So I thought it might be an IR issue which I've read much about on this board but it doesn't seem to be that apparently.

The real issue is using the EX1 as a B-Cam with an F900R and having them match up fairly accurately. The Picture Profile solution might be the best answer since the two cameras are seeing the same light source differently, and gelling the lights to fix one will distort it for the other camera.

I just wish I could find a technological explanation for this anomaly.
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Old October 15th, 2009, 11:35 AM   #5
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I didn't say the white balance circuit was inaccurate at all, I said don't take the numbers all that seriously. If your camera isn't actually balancing the picture correctly its a serious issue. If its just weird numbers it probably doesn't mean anything at all and you could chase that until your blue in the face. That's the educated guess of someone who has watched peculiar color balance numbers in different cameras for years.

On the other hand it could signal an issue if and only if your actual color balance is bad.
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Old October 15th, 2009, 12:29 PM   #6
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Thanks Leonard, the EX1 is only misbehaving with the Kino Flo flourescents so it's something I was hoping others might have experienced and remedied. In general the EX1 white balance circuitry and overall look is very accurate.
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Old October 15th, 2009, 12:48 PM   #7
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Same Issue

Bruce I too have had the same experience with my Kino's. I however have been using the daylight 5500K and the white balance usually comes out around 6500 and sometimes 11000k. When that has been the case I have adjusted through the profile.
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Old October 15th, 2009, 01:03 PM   #8
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I guess the readings of the colour temp. is not acurate. The light are seperated into 3 colours: blue/green/red and the number can only describe the mix of two colours, probably blue and red. My theory is that the different readings can be a result of different ways to create the readout and how the green colours are treated.
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Old October 15th, 2009, 01:45 PM   #9
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thanks for that feedback Ryan,

It sounds at least as if the camera is accurately reporting the white balance number, the chips are just not reading it accurately as correct color. I first noticed it with my 3200K Kino bulbs as a slightly blue-ish tint to skin tone when I set the WB to 32K preset. It sounds as if you are having the exact same issue but with daylight bulbs - so there appears to be an issue with flourescent bulbs and the camera. I wonder why Adam Wilt or someone hasn't noticed and blogged on this yet?

So the quick fix appears to be to color correct in Picture Profile and save that as Kino 32K and Kino 56K for those shooting situations.

Would love to find out why though.
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Old October 15th, 2009, 04:07 PM   #10
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If it doesn't read the temperature number accurately, what confidence can there be in setting it thru the picture profile?

If you manuall balance and it reads 4000 when you know it's actually 3200, what would lead you trust that entering 3200 thru the picture profile would be more trustworthy than entering 4000?

Both methods are suspect to me, by the numbers, but manually balancing on the white cartd has been fairly reliable for me, ignoring the numbers it reads out.
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Old October 15th, 2009, 04:57 PM   #11
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I tend to use the numbers as a rough guide- especially when comparing a camera like the EX1 to an F900, not in the same league. Nor were they designed to match each others measurements. If you white balance to the same source and frame you'll likely be more than close enough to finesse the match in post. Any good DP will tell you that relying on menus alone for color balance is not enough. You need to balance with a standard white card- hopefully one you keep with you consistently.

Noah
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Old October 15th, 2009, 05:54 PM   #12
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The really nice part about having two (non-identical) cameras play out to calibrated monitors (ECinema) is that you can really see what's fooling you and what's not.

It appears in this particular case that the Kino Flo flourescent bulbs are causing problems with the white balance circuitry of the EX1 and no such thing is occuring simultaneously with the F900R under the same bulbs. The white balance numbers under those bulbs that the EX1 is seeing as foreground are being read at 1000 degrees more than what the F900R sees them at. Of course you can manually white balance (which I do) but then the background areas lit by regular tungsten bulbs changes dramatically between the cameras - even though the foreground faces can be brought into approximate color sync. Imagine a simple sit-down interview where the foreground subject is lit with Kino Flo bulbs and the background is lit by a couple of Arri tungsten fixtures. This is the problem then, to get the EX1 to accurately see the Kino Flo bulbs at their proper temperature and not 1000 degrees cooler. For one camera (EX1 only) I can manually adjust the white balance down to where it should be and not worry about any mis-match, but with two different cameras it is much more problematic.

The obvious and simple solution is to not use Kino Flo bulbs, but I love my Diva's and really would rather understand what's happening and try and fix it with either filters, menu adjustments, or worst-case scenario send the camera into Sony for fixing - even though I doubt that would solve anything.

Now that another user has had the same experience as I have, I'm inclined to inquire into specialized filtration solutions as the most viable option.
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Old October 15th, 2009, 06:16 PM   #13
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Bruce,

Here's what I don't get about your posts:

First I've never noticed a problem with Kinoflo Diva lights and EX-1's though be honest I'm trying to remember when I neccessarily used them together. It seems like I must have since I use both often enough. However I've also never heard anyone else complain about Diva's having a problem with the Ex-1 in 2 years of the camera being around. You could be right though since I can't remember seeing it myself - maybe you've found an issue that everyone else has missed.

Second is more critical for me in that you keep referring to the color temp readout numbers which may be wildly off. Forgetting about white balance numbers -I haven't clearly seen you say that you put an F900 and an EX-1 next to each other in the same shot (going to the same monitor) and found that the EX-1 handled the Diva differently after white balancing. Its been implied but not stated clearly. Post stills of the 2 cameras if you can.

It is possible that the IR issue is involved in your situation especially if sensitive dark fabrics are involved, and the new Tiffen T1 IR is the best solution for far red contamination on the EX.

Are you sure you're using all 3200 Kino bulbs?
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Old October 15th, 2009, 06:49 PM   #14
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"I haven't clearly seen you say that you put an F900 and an EX-1 next to each other in the same shot (going to the same monitor) and found that the EX-1 handled the Diva differently after white balancing. Its been implied but not stated clearly."

The answer to this is yes, the F900R recognizes the (authentic Kino Flo Diva Tru Match 32K) bulbs at 3200K and the EX-1 white balance readout is 4500K for those same bulbs under the exact same side-by-side conditions. When the EX1 is set to 3200K preset, the skin tones lit by those bulbs tend towards a blue-ish tint - indicative of that higher temperature. I usually use a 1/4 +Green gel on the Diva lights to offset the well-know spike towards magenta, but the 4500K readout happens with or without those gels.

White balancing the EX1 to the higher temperature normalizes skin tones, but changes the background colors lit by regular tungsten units to a different hue than the F900R is displaying. When I switch the Divas out to tungsten units like Arri or Mole Richardson fresnels the problem disappears. So I am seeing a radical shift on these TruMatch bulbs and not on HMI's or tungsten fresnels.

Ryan, another poster has indicated he sees this on Kino Flo daylight bulbs also with the EX-1, so I am naturally curious about light wave frequency shifts etc. which might explain this and specific filters which might cancel the problem out.

I will be getting a Tiffen T1 IR filter soon to see if it has an effect on this problem as well as the red/black issue. Right now I am fishing for fellow EX1 travellers who've stumbled upon this issue and how/if it got solved.
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Old October 15th, 2009, 07:41 PM   #15
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Well I guess I need to test this out myself but my EX-1 is in the shop and I need to borrow a Kino so we'll see. Might be that I never had them side by side with another camera with a Diva.
This would be weird indeed if it checks out. I'll let you know what I find when I get a chance to test.
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