All my digital cameras can't pick up this color of green!

Started Jun 8, 2007 | Discussions
kelly1985 Regular Member • Posts: 292
All my digital cameras can't pick up this color of green!

One of my friend discovered that his Fuji F31 camera couldn't pick up the correct color for a green chair. The camera showed it as a pure BLUE color chair! I first didn't believe it. I told him he must have been using the wrong WB. Then, he asked all his colleague to bring all their cameras and did the same test. As many as 6 different cameras, P&S and DSLR, including 1 Nikon D200 couldn't correctly capture the green color, they all captured it as blue! Only one 3 years old SONY 4MP p&s accurately captured the green tone.

Now, I took all my camera: S5 pro, Fuji F20, and a Sony V3 p&S, and did the same test. To my surprise, they all captured the green tone as blue!!

I even fine-tuned the WB color; ie, increasing/decreasing red, decreasing blue, increasing/decreasing yellow, vice versa; it still didn't do so well.

On my F20, if I set it to WB as sunlight, then the green tone showed up quite well. But, it completely distorted colors of everything else!!!

Following are 2 sets of pictures. The one with the green chair is (almost) the correct green color of the chair, but all other items colors are distorted. For the one with the "blue" chair, it is the wrong color, but the color of all other things are more accurate.

Can someone explain why this is so?

Green chair (real-life color is even more greener)

Same green chair captured as "blue"

Green carpet (real color is more greener)

Green carpet captured as "blue"

wolfje Junior Member • Posts: 43
Re: All my digital cameras can't pick up this color of green!

What about the UV filter ? (remembering the leica M8)

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OP kelly1985 Regular Member • Posts: 292
i don't understand

can you elaborate?

wolfje Junior Member • Posts: 43
Re: i don't understand

The Leica M8 came onto market making photographs sensitive to UV. An example can be found on outbackphoto.com/reviews/equipment/leica_m8/Leica_M8_ThomasHoepker.

Especially blueish synthetic fabrics gave a purple cast onto the sensor. The answer is to use a UV filter. As most sensors today use an UV filter I suspect that a portion of the visible purple of the light-spectrum toward UV is cut-off. In your photos you will see the chair next to the green chair changing form purple to a brownish colour.

As I am typing this and looking again is see more colour changes (the carpet has less yellow). So I am wondering something else in the rendering of the colours (with the Sony) is going on.

Ruud

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GeorgeH Senior Member • Posts: 1,925
Re: All my digital cameras can't pick up this color of green!

It looks like the white balance is off in the first photo, thus the color is off.

kelly1985 wrote:

One of my friend discovered that his Fuji F31 camera couldn't pick
up the correct color for a green chair. The camera showed it as a
pure BLUE color chair! I first didn't believe it. I told him he
must have been using the wrong WB. Then, he asked all his
colleague to bring all their cameras and did the same test. As
many as 6 different cameras, P&S and DSLR, including 1 Nikon D200
couldn't correctly capture the green color, they all captured it as
blue! Only one 3 years old SONY 4MP p&s accurately captured the
green tone.

Now, I took all my camera: S5 pro, Fuji F20, and a Sony V3 p&S,
and did the same test. To my surprise, they all captured the green
tone as blue!!
I even fine-tuned the WB color; ie, increasing/decreasing red,
decreasing blue, increasing/decreasing yellow, vice versa; it still
didn't do so well.

On my F20, if I set it to WB as sunlight, then the green tone
showed up quite well. But, it completely distorted colors of
everything else!!!

Following are 2 sets of pictures. The one with the green chair is
(almost) the correct green color of the chair, but all other items
colors are distorted. For the one with the "blue" chair, it is the
wrong color, but the color of all other things are more accurate.

Can someone explain why this is so?

Green chair (real-life color is even more greener)

Same green chair captured as "blue"

Green carpet (real color is more greener)

Green carpet captured as "blue"

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wolfje Junior Member • Posts: 43
Re: i don't understand

I see I need to add something more to my second post.

If i am right there is UV reflection on the chair which isn't cut off by most sensors. As it is computed to blue (in the RGB computation) the green changes from green to blue.

The F20 seem to have a cut off in the visible purple region, so less blue is computed.

Ruud

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Kevin P Kitching
Kevin P Kitching Senior Member • Posts: 2,237
Re: All my digital cameras can't pick up this color of green!

I would assume that you have shot these under flourescent lights?

The different colour shifts are due to the way that the lights transmit light at different 'pulses'.

Try shooting the chair outdoors, or at least use the flourescent white balance on the camera.

Basic stuff, really.

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Kevin P Kitching

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earthbound_ca Senior Member • Posts: 2,236
Out of Gamut Colour

Your EXIF is stripped. What colour space are you using? sRGB?

Use Adobe RGB (1998) in JPEG or better still convert RAW to either Adobe RGB (1998) or ProPhoto RGB using Adobe's ACE conversion engine with perceptual intent with black point compensation and dithering. If your workflow is colour-managed, you will see very near to -- if not spot on -- the correct colour.

DO NOT convert from an sRGB to another colour space hoping to obtain the colour. Once a colour is missed in capture, it may be loosely approximated but never equaled. The rule of thumb is once the data is lost, it can never be recaptured (like blown highlights).

Try this suggestion. If it works, pass along the word.

PS A clue that it isn't to do with WB is that you have a wide range of colour temps available to you and within that range when you get closer to the correct green (but never equal) the other colours fall apart.

OP kelly1985 Regular Member • Posts: 292
It was in aRGB

IF so, do I still bother to convert to sRGB?

OP kelly1985 Regular Member • Posts: 292
Kevin

I have tried all WB, the sunlight one came closest to it (the one posted on my OP). The point is: if I get the chair color correct, all other things became color off. The final point is: the CCD just somehow failed to pick up that one color of green.

This happened to like over 10 different cameras of different brands.

CaptD Senior Member • Posts: 2,360
Has anyone considered that yellow and green make blue?

I would follow the earlier suggestion and take the chair outside into sunlight. Not a cloudy day or open shade either.

My thinking, rather simple is that incandescent light (yellow/amber) and green will make blue. The scenario looks like it would be flourescent, but you never know these days.

Take the chair outside, then let's see what you get... or, try it with direct flash (still not daylight, but simpler).
--
Dennis
http://dennislee.smugmug.com/gallery/2516942

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OP kelly1985 Regular Member • Posts: 292
GeorgeH

I think I wrote that I tried all different WBs, and only the sunlight one came close to captureing the green chair. But at the expense of all other color went off.

OP kelly1985 Regular Member • Posts: 292
CaptD

I tried it with Flash, and the chair came out very blue. I tried all WB with or without flash, and it seems that flash doesn't improve or degrade it.

Take it out to sunlight would defeat the purpose, since if it is so, does that mean I should take anymore picture correctly in the office (floresecent/???) light settings?

I think I am missing some light tools, oh, I didn't try the gel cover on my SB800. Wonder if it will make a difference.

Kevin P Kitching
Kevin P Kitching Senior Member • Posts: 2,237
Re: Kevin

Have you tried shooting aRGB? This wil get a wider gammut. Also, try shooting the chair using flash (with auto WB).

Does this resolve the problem? Does grass photograph green?

If all of the above fail, I would say you have a problem with your camera body & should seek assistance from Fuji.

Hope this helps.

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Kevin P Kitching

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earthbound_ca Senior Member • Posts: 2,236
Re: It was in aRGB

You decide the colour space depending upon your input/output requirements.

If the images are in-camera JPEGs using Fujfilm's in-camera Adobe RGB (1998) colour space, I strongly suggest shooting the image in RAW and converting to TIFF using Adobe Camera RAW and Adobe's output colour spaces (Adobe or Pro Photo RGB). I don't know without testing that I would even trust Fuji's RAW converter to achieve the colour accuracy offered by broader colour spaces let alone sRGB.

For the record, Fujfilm's in-camera gamuts are not as broad in all areas of the spectrum based on spectral analysis using the S2 & S3 that I've seen in the past. The inability to sort out specific colours falls squarely into this territory. In other words, not all sRGBs (or pick any other colour space) are the same: Nikon has their own variation on the theme as do Canon, Fujifilm, etc. The problem also involves mapping out-of-gamut colours to achieve an interpretation.

The common refrain in this forum has been that the Fuji cameras deliver 'pleasing results' whereas, for instance, Nikon's DSLRs offer more accurate results. Based on Fujifilm's track record, while I would hope the S5 is better, I haven't seen anything that tells me it is markedly better in this area.

While exceptions can arise, incorrect WB generally results in the same colour shift throughout a scene: small gamut colour spaces OTOH can result in misinterpreted colours within a scene (e.g. certain blues may turn out purple, certain reds may be rendered orange, etc.). Film was not altogether different in this regard.

OP kelly1985 Regular Member • Posts: 292
Re: Kevin

Kevin,

I did shoot in Adobe RGB, and tried both with and without flash. Flash didn't seem to help or hurt the color.

yes, I took many pictures of outdoor grass, trees, etc., and they are perfectly fine.

I brought this issue up, because I think there is a fault within the design of today's CCD that (under that particular situation) fails to detect the green color.

OP kelly1985 Regular Member • Posts: 292
earthboundca

just for your information regarding Nikon. I've also tried my friend's D200, and tried all available WB, and even preset WB to a grey card, the chair still came out to be blue (wrong).

I have tried a Canon, Casio, and Sony, Fuji, surprising only one 3-year old SONY 4MP P&S can accurately capture the green color. (this is not a pro-SONY, and blast FUJI topic!!) However, I tried my newer SONY P&S, it captured incorrectly as BLUE.

If anyone of you have some kind of a green fabric chair, carpet, draperies, try it to see if you have the same problem

earthbound_ca Senior Member • Posts: 2,236
Re: earthboundca

And my only questions are, have you shot the images RAW with an accurate WB and used a larger gamut colour space for the output TIFF -- and with the last gasp -- in 16 bit in a properly managed colour workflow?

I fully agree that different devices will capture different gamuts (in fact, that was one of my points). At some point, you will find that all current devices will not render every colour in the spectrum regardless of colour space selection which, in and of itself, is not an infinite colour palate. It's a matter of coming to understand your input and output devices' limitations.

mjt Senior Member • Posts: 1,044
Re: All my digital cameras can't pick up this color of green!

hi Kelly ...

this is going to be a stretch, but, i dont suppose you have access to a color temperature meter? is so, can you provide the results of its readings?

regards, michael

Pkphoto Contributing Member • Posts: 528
Re: All my digital cameras can't pick up this color of green!

very strange story, and results, you gave me the idea to make some tests, but which light source do you use ? and in what kelvin area?

And as I understand you speak about "green" textures of chairs or carpets, no plastic material? that means that the color is not a natural one as a tree or natural places...?

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