Strange color tone - is that due to coating or WB problem?

Bui · 04-27-2017, 05:00 AM

Hi there,

I would like to ask you something that I have been wondering: some of pictures from certain lenses have some strong color tone (purple or blue), for example, most of the photos from my Super Takumar 105mm 2.8 have a purple tone (I think I shot them at quite large aperture):

Or last week I took my daughter to a farm, and here are some images I took with the DA 40 Ltd in the cage, there is a strange blue tone, I'm pretty sure there was no blue light in there:

So could that be problem with my WB error (most of the time I leave it in auto anyway), the coating of the lenses, or other reasons?

Thanks.

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Last edited by Bui; 11-26-2017 at 12:50 AM.

photoptimist · 04-27-2017, 05:25 AM

Yes, some lenses have different color casts -- if you use a fixed WB (e.g., sunlight) and shoot the same scene with different lenses, you'll see slightly different colors.

But in this case, I'm seeing a lot of blue coming from parts of the scene being lit by blue sky (the bench in shadow, the house wall in shadow, and the petting zoo interior which probably had large open doors facing the blue sky).

It's really easy to not notice color casts created by different kinds of light in a scene because the human eye & brain have AWB on steroids. The eye and brain are extremely good at seeing the colors they think they should seen rather than the colors that really are physically there.

Bui · 04-27-2017, 05:29 AM

Originally posted by photoptimist

Yes, some lenses have different color casts -- if you use a fixed WB (e.g., sunlight) and shoot the same scene with different lenses, you'll see slightly different colors.

But in this case, I'm seeing a lot of blue coming from parts of the scene being lit by blue sky (the bench in shadow, the house wall in shadow, and the petting zoo interior which probably had large open doors facing the blue sky).

It's really easy to not notice color casts created by different kinds of light in a scene because the human eye & brain have AWB on steroids. The eye and brain are extremely good at seeing the colors they think they should seen rather than the colors that really are physically there.

Thank you, I think you're right, I didn't notice or remember the blue sky outside could affect the light.

**othar** · 04-27-2017, 05:35 AM

The pictures of your Super Takumar seem fine on my tablet although I admit that doesn't necessarily mean much. I ran into a problem with auto WB and my Pentacon 300/4 once. I got totally blue pictures on an overcast day (I was glad I shot raw+ or all pictures would have been unusable). Since then I don't use AWB for that lens anymore (just daylight/overcast/open shade/... and I finetune the colors in pp if necessary. With my other lenses I never had any issues with AWB so it is possible that the camera has some issues with certain older lenses.
With your DA 40mm lens I think your problem is, that there are multible lightsources in the stables that don't agree with each other. The main lightsource is the artificial light which is very warm and that's why the natural light appears to be blue.

CarlJF · 04-27-2017, 05:59 AM - **1 Like**

Originally posted by photoptimist

The eye and brain are extremely good at seeing the colors they think they should seen rather than the colors that really are physically there.

One of the most extreme exemple of this being "The Dress". BTW, I see it white and gold...

C_Jones · 04-27-2017, 07:25 AM

It looks like there is a blue material covering something in the 4th image that looks like a window with shutters on it in the background (upper left of image). Maybe that type of covering was being used in different parts of the building to cover window areas, causing the blue light. In images 1 and 2 the toning does not seem largely overemphasized. Blue reflections of the sky from the water are natural.

tvdtvdtvd · 04-27-2017, 07:58 AM

Originally posted by CarlJF

One of the most extreme exemple of this being "The Dress". BTW, I see it white and gold...

I see blue and brown. The brown is obviously the washed out black areas. No matter how long I study the image, I simply
can not see white and gold, though I do see how the blue areas could be interpreted as 'white' in a very shady scene. The image
is back lit, after all. And yet, the dress is confirmed to actually be blue and black. Curiously, I just showed the image to my wife
and asked her what colors she sees in the dress. "White and mustard." I'm still trying to see the white....

Na Horuk · 04-27-2017, 10:14 AM

Some lenses have a color cast-
But I dont think there is a big problem with those lenses. Here is what I think:
a) Post processing: The jpeg mode or PP style can emphasize certain colors more than others.
b) LED lights. In some cases, especially indoors at events, LED lights can be quite annoying. They are strong, but they only have one color frequency. On digital cameras, this stands out too much
c) White balance. Especially in extreme cases, like a blue sky, sunny day at the blue sea. In those cases, things actually are more blue than anything. Your brain automatically corrects, but the camera does not correct to the same degree. Getting a 'natural-looking WB' is really difficult in those cases.

**acoufap** · 04-27-2017, 11:14 AM

I’d like to mention another important point besides the lenses and color temperature characteristics. Na Horuk already set a hint on this.

Subjects can only reflect the light spectrum available. So it depends on the light source what colors the camera can record. This is a general issue.

A simple experiment: use a cheap LED light source and prevent the scenery from other light sources. Take a photograph of a subject of different colors, by example a book shelf with books that show some strong red covers. After that have a look at the photograph on a calibrated monitor.

In many cases you may not see proper reds. The reds are often captured as orange color. The reason is an uneven light spectrum of your light source where red frequences are very weak - something very common! In many areas it is a must that colors are reproduced correctly. So
a special index was introduced. That index indicates the light spectrum completeness of light sources and is called - CRI Color Rendering Index.

If you want to use artificial light and you want to get proper colors of the whole spectrum check if the described CRI of the light source is described as a number greater than 90, 100 would be perfect. With a good flash you’ll get all colors perfect or nearly perfect. So we can conclude that this kind of light source is one with a very good and complete color spectrum - a little nice sun.

The artificial light in the stable surely isn't perfect. This is why the child's jacket color may look a bit strange.

At the end I’d say, your pictures show a veriety of issues - but nothing really unusual.

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04-27-2017, 05:25 AM	#2
photoptimist Pentaxian Join Date: Jul 2016 Photos: Albums Posts: 5,122	Yes, some lenses have different color casts -- if you use a fixed WB (e.g., sunlight) and shoot the same scene with different lenses, you'll see slightly different colors. But in this case, I'm seeing a lot of blue coming from parts of the scene being lit by blue sky (the bench in shadow, the house wall in shadow, and the petting zoo interior which probably had large open doors facing the blue sky). It's really easy to not notice color casts created by different kinds of light in a scene because the human eye & brain have AWB on steroids. The eye and brain are extremely good at seeing the colors they think they should seen rather than the colors that really are physically there.

04-27-2017, 05:29 AM	#3
Bui Veteran Member Join Date: Nov 2016 Photos: Gallery Posts: 316 Original Poster	Originally posted by photoptimist Yes, some lenses have different color casts -- if you use a fixed WB (e.g., sunlight) and shoot the same scene with different lenses, you'll see slightly different colors. But in this case, I'm seeing a lot of blue coming from parts of the scene being lit by blue sky (the bench in shadow, the house wall in shadow, and the petting zoo interior which probably had large open doors facing the blue sky). It's really easy to not notice color casts created by different kinds of light in a scene because the human eye & brain have AWB on steroids. The eye and brain are extremely good at seeing the colors they think they should seen rather than the colors that really are physically there. Thank you, I think you're right, I didn't notice or remember the blue sky outside could affect the light.

04-27-2017, 05:35 AM	#4
othar Site Supporter Join Date: May 2014 Location: Linz Photos: Albums Posts: 3,098	The pictures of your Super Takumar seem fine on my tablet although I admit that doesn't necessarily mean much. I ran into a problem with auto WB and my Pentacon 300/4 once. I got totally blue pictures on an overcast day (I was glad I shot raw+ or all pictures would have been unusable). Since then I don't use AWB for that lens anymore (just daylight/overcast/open shade/... and I finetune the colors in pp if necessary. With my other lenses I never had any issues with AWB so it is possible that the camera has some issues with certain older lenses. With your DA 40mm lens I think your problem is, that there are multible lightsources in the stables that don't agree with each other. The main lightsource is the artificial light which is very warm and that's why the natural light appears to be blue.

04-27-2017, 05:59 AM - 1 Like	#5
CarlJF Veteran Member Join Date: Sep 2014 Location: Quebec City Posts: 1,185	Originally posted by photoptimist The eye and brain are extremely good at seeing the colors they think they should seen rather than the colors that really are physically there. One of the most extreme exemple of this being "The Dress". BTW, I see it white and gold...

04-27-2017, 07:25 AM	#6
C_Jones Pentaxian Join Date: Sep 2012 Location: NY Photos: Gallery \| Albums Posts: 6,084	It looks like there is a blue material covering something in the 4th image that looks like a window with shutters on it in the background (upper left of image). Maybe that type of covering was being used in different parts of the building to cover window areas, causing the blue light. In images 1 and 2 the toning does not seem largely overemphasized. Blue reflections of the sky from the water are natural.

04-27-2017, 07:58 AM	#7
tvdtvdtvd Veteran Member Join Date: Jan 2010 Posts: 1,665	Originally posted by CarlJF One of the most extreme exemple of this being "The Dress". BTW, I see it white and gold... I see blue and brown. The brown is obviously the washed out black areas. No matter how long I study the image, I simply can not see white and gold, though I do see how the blue areas could be interpreted as 'white' in a very shady scene. The image is back lit, after all. And yet, the dress is confirmed to actually be blue and black. Curiously, I just showed the image to my wife and asked her what colors she sees in the dress. "White and mustard." I'm still trying to see the white....

04-27-2017, 10:14 AM	#8
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Some lenses have a color cast- But I dont think there is a big problem with those lenses. Here is what I think: a) Post processing: The jpeg mode or PP style can emphasize certain colors more than others. b) LED lights. In some cases, especially indoors at events, LED lights can be quite annoying. They are strong, but they only have one color frequency. On digital cameras, this stands out too much c) White balance. Especially in extreme cases, like a blue sky, sunny day at the blue sea. In those cases, things actually are more blue than anything. Your brain automatically corrects, but the camera does not correct to the same degree. Getting a 'natural-looking WB' is really difficult in those cases.

04-27-2017, 11:14 AM	#9
acoufap Site Supporter Join Date: Jan 2011 Location: Munich, Germany Photos: Gallery \| Albums Posts: 4,187	I’d like to mention another important point besides the lenses and color temperature characteristics. Na Horuk already set a hint on this. Subjects can only reflect the light spectrum available. So it depends on the light source what colors the camera can record. This is a general issue. A simple experiment: use a cheap LED light source and prevent the scenery from other light sources. Take a photograph of a subject of different colors, by example a book shelf with books that show some strong red covers. After that have a look at the photograph on a calibrated monitor. In many cases you may not see proper reds. The reds are often captured as orange color. The reason is an uneven light spectrum of your light source where red frequences are very weak - something very common! In many areas it is a must that colors are reproduced correctly. So a special index was introduced. That index indicates the light spectrum completeness of light sources and is called - CRI Color Rendering Index. If you want to use artificial light and you want to get proper colors of the whole spectrum check if the described CRI of the light source is described as a number greater than 90, 100 would be perfect. With a good flash you’ll get all colors perfect or nearly perfect. So we can conclude that this kind of light source is one with a very good and complete color spectrum - a little nice sun. The artificial light in the stable surely isn't perfect. This is why the child's jacket color may look a bit strange. At the end I’d say, your pictures show a veriety of issues - but nothing really unusual.