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Archive 2015Can someone explain how lenses affect color?
p.2 #1Can someone explain how lenses affect color?
johnctharp wrote:
With Sony, no RAW is safe...
With Sony, no RAW is safe...
Sep 07, 2015 at 12:41 PM
p.2 #2Can someone explain how lenses affect color?
The R28v2 is a lot newer than mine, but this test may somewhat confirm the very vague impression I have that my R lenses (Mandler Summiluxes 35, 50, 80, at least on my Sony A7x bodies) are generally more temperamental than Zeiss optics, especially modern Zeiss optics, which are to me unflappable and a bit boring. In particular R lenses tend to look wonderful in daylight, like they're overflowing with colors, but often unpleasant in low and artificial light.
Sep 07, 2015 at 12:45 PM
p.2 #3Can someone explain how lenses affect color?
Well then, you really should be asking TWO questions:
1) What effect do native electric/full manual lenses have on the camera's (or the raw-converter's) auto-WB
2) What color effects do different lenses give
If you want to know what effect the LENS gives, then you should shoot with a locked down manual WB. Some lenses tilt a few mired, but actually that's a very small part of the main effect.
That effect (after accurate WB settings) is often a very subtle one, at least when you compare lenses of similar quality. Most of it can be attributed to how different parts of the spectrum blur differently due to two dominating optical effects: Longitudinal CA and differential scatter.
They both have close to zero effect on solid surfaces like large patches of flat color. But they can have a noticeable effect on images with lots of fine high-contrast detail.
Let's say you have a lens with really bad near-UV LoCA; that will lower the amount of blue in small point-shaped highlights making them "warmer", and increase the amount of blue in small dark areas making them "colder" - while having no effect on larger areas without detail in the photo.
................
But really... Most of the "lens-difference" in color is either the camera WB reacting strangely to UV or IR content (this is mostly in cameras with separate WB-sensors, not mirrorless cameras that measure WB directly on the image sensor), or just a post-processing effect of lenses having different amounts of absolute stray light (measured as lens global contrast value, low-frequency MTF)
Color is defined by contrast between different parts of the visible spectrum, and cameras measure color just like your eyes, but not with the exact same filters to separate the opposing spectras. Zero contrast between the filtered channels means zero color, neutrality. You have to have difference between at least two channels to get a color signal. And then you have two separate issues:
1) The way contrast is transferred differs between two different parts of the spectrum in a single lens
2) The way total contrast is transferred for the whole spectrum differs between two lenses.
Most raw converters try to find a black-point in the raw file to set as "zero". And that value changes automatically within a certain accepted correction range, even when you think you do every setting manually. This is part of the file interpretation even before the image is handed over to the manual controls on the surface of the programs. So it's hard to say which lenses do what in most cases - since raw converter "pull" low contrast lenses down to black again, artificially increasing contrast to make the rest of the image processing chain work "right" - or maybe more correctly: "as intended"...
Think about the lens with bad blue LoCA as I mentioned in the beginning - what will happen here?
Well, since small dark patches will be contaminated by stray blue light, the raw converter will compensate by pulling the black-point of that channel. This will then make for a LACK of blue in the mid range of the blue channel. Having to much blue in the blacks made the image have to little blue in the midtones. Logical huh?
The effects this has on color is strangely counter-intuitive. Unless you're kind of strange in the head (like me...) I'd suggest not trying to really analyze what's really happening behind the scenes here. Stuff gets REALLY complicated, really fast when you dig a bit deeper. This was a long post, but I'm barely scratching the surface of the SHORT version of the explanations available.
Just make sure your WB is adjusted correctly for the main image information area, no matter what lens you use. Then the differences will be quite small. Noticeable in an A/B/X visual test, but not really something serious. To get serious differences, you have to mix up some lenses of seriously differing quality levels.
Never try to find differences between images with different white points. That is futile, then you're looking at differences in camera and raw converter processing chains, not at differences in lens color rendition.
1) What effect do native electric/full manual lenses have on the camera's (or the raw-converter's) auto-WB
2) What color effects do different lenses give
If you want to know what effect the LENS gives, then you should shoot with a locked down manual WB. Some lenses tilt a few mired, but actually that's a very small part of the main effect.
That effect (after accurate WB settings) is often a very subtle one, at least when you compare lenses of similar quality. Most of it can be attributed to how different parts of the spectrum blur differently due to two dominating optical effects: Longitudinal CA and differential scatter.
They both have close to zero effect on solid surfaces like large patches of flat color. But they can have a noticeable effect on images with lots of fine high-contrast detail.
Let's say you have a lens with really bad near-UV LoCA; that will lower the amount of blue in small point-shaped highlights making them "warmer", and increase the amount of blue in small dark areas making them "colder" - while having no effect on larger areas without detail in the photo.
................
But really... Most of the "lens-difference" in color is either the camera WB reacting strangely to UV or IR content (this is mostly in cameras with separate WB-sensors, not mirrorless cameras that measure WB directly on the image sensor), or just a post-processing effect of lenses having different amounts of absolute stray light (measured as lens global contrast value, low-frequency MTF)
Color is defined by contrast between different parts of the visible spectrum, and cameras measure color just like your eyes, but not with the exact same filters to separate the opposing spectras. Zero contrast between the filtered channels means zero color, neutrality. You have to have difference between at least two channels to get a color signal. And then you have two separate issues:
1) The way contrast is transferred differs between two different parts of the spectrum in a single lens
2) The way total contrast is transferred for the whole spectrum differs between two lenses.
Most raw converters try to find a black-point in the raw file to set as "zero". And that value changes automatically within a certain accepted correction range, even when you think you do every setting manually. This is part of the file interpretation even before the image is handed over to the manual controls on the surface of the programs. So it's hard to say which lenses do what in most cases - since raw converter "pull" low contrast lenses down to black again, artificially increasing contrast to make the rest of the image processing chain work "right" - or maybe more correctly: "as intended"...
Think about the lens with bad blue LoCA as I mentioned in the beginning - what will happen here?
Well, since small dark patches will be contaminated by stray blue light, the raw converter will compensate by pulling the black-point of that channel. This will then make for a LACK of blue in the mid range of the blue channel. Having to much blue in the blacks made the image have to little blue in the midtones. Logical huh?
The effects this has on color is strangely counter-intuitive. Unless you're kind of strange in the head (like me...) I'd suggest not trying to really analyze what's really happening behind the scenes here. Stuff gets REALLY complicated, really fast when you dig a bit deeper. This was a long post, but I'm barely scratching the surface of the SHORT version of the explanations available.
Just make sure your WB is adjusted correctly for the main image information area, no matter what lens you use. Then the differences will be quite small. Noticeable in an A/B/X visual test, but not really something serious. To get serious differences, you have to mix up some lenses of seriously differing quality levels.
Never try to find differences between images with different white points. That is futile, then you're looking at differences in camera and raw converter processing chains, not at differences in lens color rendition.
Sep 07, 2015 at 04:09 PM
p.2 #4Can someone explain how lenses affect color?
The existence of global color differences between lenses is well known. Coatings play a substantial role, because their anti-reflective properties are not constant over the spectrum.
The OP shows two pictures, a warmer and a colder one, but their order is different between the first two scenes. I see only two possibilities. He either mixed up the lenses, or some form of auto white balance renders the entire test invalid.
The OP shows two pictures, a warmer and a colder one, but their order is different between the first two scenes. I see only two possibilities. He either mixed up the lenses, or some form of auto white balance renders the entire test invalid.
Sep 08, 2015 at 10:19 AM
p.2 #5Can someone explain how lenses affect color?
Thank you TheSeude, glad someone took this on. Lenses definitely have a non-zero effect on color, but every time I've ever seen a post like this the differences they're seeing are from processing, sensors, white balance, etc., not lenses. Actual color differences between lenses are pretty slight when you neutralize everything.
Sep 08, 2015 at 11:43 AM
p.2 #6Can someone explain how lenses affect color?
redisred wrote:
Thank you TheSeude, glad someone took this on. Lenses definitely have a non-zero effect on color, but every time I've ever seen a post like this the differences they're seeing are from processing, sensors, white balance, etc., not lenses. Actual color differences between lenses are pretty slight when you neutralize everything.
Here are 'pure' data without the uncertainty of sensors, processing, white balance etc. I got these spectrometer data from a physics PhD student whose name I don't recall right now. We see transmission measurements for three Y/C lenses and a loupe.
For what it is worth, my Distagon 2.8/21 Y/C is noticeably colder than my other lenses - but I don't have spectrometer data to back it up.
http://toothwalker.org/temp/fm/transmission.png
Thank you TheSeude, glad someone took this on. Lenses definitely have a non-zero effect on color, but every time I've ever seen a post like this the differences they're seeing are from processing, sensors, white balance, etc., not lenses. Actual color differences between lenses are pretty slight when you neutralize everything.
Here are 'pure' data without the uncertainty of sensors, processing, white balance etc. I got these spectrometer data from a physics PhD student whose name I don't recall right now. We see transmission measurements for three Y/C lenses and a loupe.
For what it is worth, my Distagon 2.8/21 Y/C is noticeably colder than my other lenses - but I don't have spectrometer data to back it up.
http://toothwalker.org/temp/fm/transmission.png
Sep 09, 2015 at 10:01 AM
p.2 #7Can someone explain how lenses affect color?
Yes RAW files get tweaked for sure. But that's not what's happening.
What you are seeing is difference in the glass. I've been on this topic for a while now. Spent a lot of money buying testing and then selling off various lenses. Sensors also don't help!
No real conclusion here as even companies aren't as consistent as I'd like. Especially old glass vs new/modern glass. And most of my testing ends with strong personal preferences for one lens over the other. Sensors also play a part in this, as they see colors differently then one another. And oddly enough I've seen a big enough difference between a first year 50Lux and a current year (2015) 50Lux to make me scratch my head.
On the M240 the 35FLE is a great example of this. I wish it rendered more blue/red less green/yellow. If it did this, it would be perfect. One of the reasons I don't use is in my personal day to day work. I find the 75APO renders more blue which I like, but it's difficult to use at work with the 35FLE because of the vast difference in colors (but I have no choice I have to make them work together). The 50APO has a bit more red then blue, which can be difficult but still better then the green/yellow and more preferable for my day to day work. I could go on.. The differences are there you just have to play around to see them.
The only advice I can give is.. You can white balance till the cows come home, but one color will effect all other colors. So at the end of the day it's best to start with the equipment that gives you closest to your preferred look. Then use that said equipment and adjust as needed. For people who can get along with one or two FLs they're fine. For the ones that need multiple FLs it gets tricky.
What you are seeing is difference in the glass. I've been on this topic for a while now. Spent a lot of money buying testing and then selling off various lenses. Sensors also don't help!
No real conclusion here as even companies aren't as consistent as I'd like. Especially old glass vs new/modern glass. And most of my testing ends with strong personal preferences for one lens over the other. Sensors also play a part in this, as they see colors differently then one another. And oddly enough I've seen a big enough difference between a first year 50Lux and a current year (2015) 50Lux to make me scratch my head.
On the M240 the 35FLE is a great example of this. I wish it rendered more blue/red less green/yellow. If it did this, it would be perfect. One of the reasons I don't use is in my personal day to day work. I find the 75APO renders more blue which I like, but it's difficult to use at work with the 35FLE because of the vast difference in colors (but I have no choice I have to make them work together). The 50APO has a bit more red then blue, which can be difficult but still better then the green/yellow and more preferable for my day to day work. I could go on.. The differences are there you just have to play around to see them.
The only advice I can give is.. You can white balance till the cows come home, but one color will effect all other colors. So at the end of the day it's best to start with the equipment that gives you closest to your preferred look. Then use that said equipment and adjust as needed. For people who can get along with one or two FLs they're fine. For the ones that need multiple FLs it gets tricky.
Sep 09, 2015 at 11:17 AM
p.2 #8Can someone explain how lenses affect color?
as already mentioned, using AWB can give you some crazy different results. using identical processing and white balance temperature settings i usually get very consistent differences between any pair of lenses (though i don't shoot native lenses except for the rx1) independent of the type of light (though backlighting can produce serious flare related exceptions). i take this to indicate that the difference i see in these comparisons are due largely to the transmission differences between lenses at different wavelengths.
some patterns i've noticed between brands: contax and pentax lenses tend to be redder/yellower than any of my other lenses, leicas and rokkors tend to be bluer/greener, and others seem less consistent (the rokkors seem to have the most consistent color across different lenses). manually setting white balance to the same target within the scene usually gets rid of all the obvious color castes but there are still color differences.
for fun here's a few lens comparisons with crops from different lenses next to each other to see color differences (and other things). all are processed identically (except for some possible exposure compensation in post to equalize exposure) with the same white balance setting (usually "daylight").
a bunch of normal lenses at f/8 on an a7 at infinity
bunch of normal lenses at various aperture on a NEX-7 at close distance
c/y 35/1.4 vs leica m 35/1.4 pre-asph at f/1.4 on a NEX-7 at infinity
bunch of lenses at near distance on a NEX-3
some patterns i've noticed between brands: contax and pentax lenses tend to be redder/yellower than any of my other lenses, leicas and rokkors tend to be bluer/greener, and others seem less consistent (the rokkors seem to have the most consistent color across different lenses). manually setting white balance to the same target within the scene usually gets rid of all the obvious color castes but there are still color differences.
for fun here's a few lens comparisons with crops from different lenses next to each other to see color differences (and other things). all are processed identically (except for some possible exposure compensation in post to equalize exposure) with the same white balance setting (usually "daylight").
a bunch of normal lenses at f/8 on an a7 at infinity
bunch of normal lenses at various aperture on a NEX-7 at close distance
c/y 35/1.4 vs leica m 35/1.4 pre-asph at f/1.4 on a NEX-7 at infinity
bunch of lenses at near distance on a NEX-3
Sep 09, 2015 at 12:29 PM
AmbientMike
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p.2 #9Can someone explain how lenses affect color?
Different lenses give different color. I've seen warm, cool, and a yellowish green cast, in addition to neutral.
I saw warm, cool , and yellow green (perfect for the swampy area I was photographing at the time) from the same manufacturer.
The 180 Tamron + the 80-200/2.8 gave similar/identical color. Interesting since they were made different times.
It's not real noticable unless you do a side by side comparison, and can theoretically be fixed in pp, so I try to ignore it to keep my sanity.
I find it More enjoyable to just grab a lens and shoot, too. As you noticed, sometimes one lens is better, sometimes, the other.
I saw warm, cool , and yellow green (perfect for the swampy area I was photographing at the time) from the same manufacturer.
The 180 Tamron + the 80-200/2.8 gave similar/identical color. Interesting since they were made different times.
It's not real noticable unless you do a side by side comparison, and can theoretically be fixed in pp, so I try to ignore it to keep my sanity.
I find it More enjoyable to just grab a lens and shoot, too. As you noticed, sometimes one lens is better, sometimes, the other.
Sep 11, 2015 at 11:08 AM
AmbientMike
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p.2 #10Can someone explain how lenses affect color?
Color temperature of the light entering the lens plays a big role.
Sep 11, 2015 at 11:17 AM
p.2 #11Can someone explain how lenses affect color?
Maybe I missed it somewhere in the thread but I'll mention it anyway: I get different colours shooting wide open compared to when stopped down. Most of my fast lenses do this. Here I say "most" only because one should never say "all" or "never" or "always"...
As I try to stay sane an practical about everything when taking images I just ignore it and adjust the images to my taste in post processing. But, for anyone wanting to dig another step deeper i offer this variable.
I guess applications like Rawdigger can help you lose your minds objectively.
...and I have enjoyed reading this far.
As I try to stay sane an practical about everything when taking images I just ignore it and adjust the images to my taste in post processing. But, for anyone wanting to dig another step deeper i offer this variable.
I guess applications like Rawdigger can help you lose your minds objectively.
...and I have enjoyed reading this far. Sep 11, 2015 at 11:55 AM
p.2 #12Can someone explain how lenses affect color?
AmbientMike wrote:
Color temperature of the light entering the lens plays a big role.
Any scientific proof to that?
Color temperature of the light entering the lens plays a big role.
Any scientific proof to that?
Sep 12, 2015 at 03:50 AM