Yellow images

[billh]

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The other thing my M8 has started doing (besides playing dead) is giving me garish, yellow color where there is none in the scene. This is an example. It was taken with the APO75, with no lens detection set, and daylight color balance chosen. The yellow is so bad in most images where this occurs that I cannot remove it in C1. I can probably get rid of it in PS, but I would love to know why this is happening. Is this somehow related to the issue of the camera not turning on?

 

Thanks,

 

Bill

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[ho_co]

Bill--

You didn't say whether you were using an IR-cut filter.

 

In foliage shots, I have found that shooting without IR filter can make the greens turn quite yellow. Maybe the paint here also reflects a large amount of IR. (I take it the paint is white.)

 

Since we can't see IR, the only way to tell for sure is by comparison shots, with and without filter.

 

Just a guess.

 

--HC

[rvaubel]

Garish yellow? You got to be kidding. That slight cast is something that PS would eliminate in about 2 seconds.

....nice dogs though

 

Rex

[billh]

Garish yellow? You got to be kidding. That slight cast is something that PS would eliminate in about 2 seconds.

....nice dogs though

 

Rex

 

Maybe your monitor is not calibrated? It is on both dogs a and the water, as well as elsewhere, and it to remove it you need to work in layers and remove or desaturate the yellow in different amounts in various areas of the images. This is a relatively simple one but others are more complex, and I have no desire to spent that much time on each snapshot.

 

HC, I did not have the IR filter on - I have not been using them since the camera returned, and have been getting beautiful color with the camera. I’ll try the filter and see what the different is with and without it. I have the new firmware and three coded lenses (the 28 f2.0 and f2.8 and the 50 ASPH). Do I need to remember to switch from coded to no coding when I switch to a non coded lens?

 

Bill

[rvaubel]

Maybe your monitor is not calibrated? It is on both dogs a and the water, as well as elsewhere, and it to remove it you need to work in layers and remove or desaturate the yellow in different amounts in various areas of the images. This is a relatively simple one but others are more complex, and I have no desire to spent that much time on each snapshot.

 

HC, I did not have the IR filter on - I have not been using them since the camera returned, and have been getting beautiful color with the camera. I’ll try the filter and see what the different is with and without it. I have the new firmware and three coded lenses (the 28 f2.0 and f2.8 and the 50 ASPH). Do I need to remember to switch from coded to no coding when I switch to a non coded lens?

 

Bill

 

Apparently you are not shooting in RAW. If you were that minor color cast could be removed in about 2 seconds

 

I kinda like the dogs a bit yellow

 

Rex

[Bob Ross]

My guess: When your camera died and came back to life, it reverted to Auto White Balance. This is presuming that you use a preset WB setting. It happened to me yesterday when I saved some settings to a User Profile and went back to User Profile 0 and wondered why I was getting inconsistant colors.

Bob

[Bob Ross]

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My Fix: This was done in PWP and I addressed only the color balance and highlight detail recovery. The big question is does this approximate what you saw or wanted? It is definately a quick fix.

Bob

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Final version

[ho_co]

HC, I did not have the IR filter on - I have not been using them since the camera returned, and have been getting beautiful color with the camera. I’ll try the filter and see what the different is with and without it. I have the new firmware and three coded lenses (the 28 f2.0 and f2.8 and the 50 ASPH). Do I need to remember to switch from coded to no coding when I switch to a non coded lens?

Bill--I usually also get good color without the IR filter, but one can't predict the presence of IR.

 

As for menu-switching between coded and uncoded lenses, the proper answer is yes. Sean Reid has noted that when lens-ID is "on" with uncoded lenses, the camera can see a screw or smudge and assign a (wrong) lens identity. But in fact, I don't always remember to switch the menu and haven't yet been bitten.

 

But I'm just guessing, and I like Bob's answer perhaps better. We may just be looking at the M8's notorious problems with white balance.

 

The dogs are beautiful. The yellow seems stronger on their wetter undersides, as if it were being reflected from the boat. As you said, the yellow cast isn't even across the image and might be a reflection. That's consistent with reflection of any color, IR or not; if the boat were blue, the blue would also be reflected in their coats. And they've got that quizzical canine expression that seems to say they've noticed something you haven't....

 

--HC

[Guest tummydoc]

Bill, what colour is the boat actually? I'm trying to understand why the white on the dog's snout came out pure white if the rest of his fur turned yellow, unless the boat was yellow and it's a reflection. It's a pity you didn't have a little inexpensive point-and-push digital at hand so we could see what the colours should really look like.

[Guest WPalank]

Bill,

I did a quickfix by going into CS3 and adding a Curves Adjustment layer. Since Blue is the opposite of Yellow I went to the "Blue Channel" only, added a point by Command-clicking on the water (where I thought the colorcast was most obvious and bumped the curve upwards (towards more blue) until it disappeared.

My assumption is that the boat really is yellow?!

Cheerrs,

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[billh]

Hi guys,

 

I can fix it too, but it is time consuming, and I would much rather understand why it suddenly started doing this. By the way Rex, I always, and only shoot RAW. Do you also like blacks a bit magenta? Each to his own, I suppose.

 

Someone suggested a possible issue with the SD card, so I switched cards and used the camera this morning , and most of those images were OK.

 

Vinay, I don’t remember the color of the boat - I just saw these guys and snapped them quickly. Maybe like HC says, we are simply looking at the infamous M8 color balance - but then again, both times when this happened to me I was using a specific balance, daylight yesterday, and before that, the shadow setting.

 

I’ll post some normal M8 files from a few days ago - the color is nice there. in fact I was shooting the Noctilux on the M8 and the Canon 50 f1.2 on the 1Ds2, and I much preferred the M8 image color and look.

[stunsworth]

Since the dogs' muzzle is white I don't think it's a white balance issue. I'd tend to either it being an IR issue of some kind caused by the paint/surface of the boat, or the boat really is yellow, but the human eye doesn't see it as such.

[Guest tummydoc]

Why would the white fur of the dog's snout not reflect IR whilst his other white fur does, unless it is reflecting IR that has reflected up from the boat? Another question, why would white boat paint turn yellow due to IR reflection? Since white by definition reflects all or nearly all visible wavelengths, wouldn't IR reflection be picked up by an IR-sensitive camera as red?

[stunsworth]

Why would the white fur of the dog's snout not reflect IR whilst his other white fur does, unless it is reflecting IR that has reflected up from the boat? Another question, why would white boat paint turn yellow due to IR reflection? Since white by definition reflects all or nearly all visible wavelengths, wouldn't IR reflection be picked up by an IR-sensitive camera as red?

 

The fur that appears yellow is downward facing and could well be affected by reflection from the colour of the boat. If you ever watch snooker look at the colour of the players' skin when they are leaning over the table to take a shot and you'll see what I mean. It is also possible that it is actually a different colour than the muzzle.

 

What I said was that the yellow of the boat could be _either_ an IR issue, or it could be that the eye is being tricked into thinking that it's white - in much the same way that a scene illuminated by fluorescent lighting appears normal to the naked eye, but green to colour photographic film.

 

IR reflection is not necessarily picked up by an IR sensitive camera as red. If that was the case we would never have had a magenta problem, rather it would have been a red problem.

[Guest tummydoc]

What I said was that the yellow of the boat could be _either_ an IR issue

 

Ok, but follow my reasoning here: let's postulate that both the boat and dog are basically white. If the boat looks yellow to the M8 because of IR reflection, why does the underside of the dog also look yellow, when it follows from the snout being white that the dog's fur does not reflect IR? The dog's fur should have absorbed the IR and look perhaps shadowed but nonetheless not yellow. Where have there been instances of a black-cum-magenta item reflecting it's magenta-ness onto another nearby item? In fact there are numerous examples of two adjacent black items where only one has been seen as magenta by the M8's errant sensor. This is why I do not see how the problem in this case is due to IR.

 

IR reflection is not necessarily picked up by an IR sensitive camera as red. If that was the case we would never have had a magenta problem, rather it would have been a red problem.

 

True, the M8's skewed response to IR is compounded with its response to the visible spectrum. That is why blacks appear magenta and greens appear yellow. What I don't understand is why white would appear yellow as well.

[stunsworth]

Vinay, I'm just speculating, this isn't something I can remember noticing in any of the 6500+ frames I've shot.

 

In the photograph the light is coming from the right. The yellow fur is slightly shaded by the dog. It could be picking up more reflected light from the boat than the snout, which is full sunlight.

[Guest tummydoc]

Yes, I am not arguing with you, just speculating as well. The shroud beneath the wheel may or may not be made of the same material as the hull, but most likely it's metal vs glass fibre or wood, yet it exhibits the same colour. The guage box sitting atop the shroud appears to be made of metal also, yet it looks white. So I'm speculating that the boat is at least partly some shade of yellow, which would explain perfectly why the dog's white fur would look equally yellow (from reflection) despite an obviously different response to IR than the materials comprising the boat. It appears to me the O.P. overstated the severity of the colour issue and the intricacy of resolving it. I believe he could not remove the "garish" yellow because he was incorrect that there was "none in the scene", although perhaps it was magnified by the M8's atrocious AWB. Again, speculation, but all else doesn't add up.

[AlanG]

I think somebody has to go back to the boat and take a look at it.

 

Why not show us some other images where you see this "yellow problem."

[rvaubel]

I think somebody has to go back to the boat and take a look at it.

 

Why not show us some other images where you see this "yellow problem."

 

Really. I've never seen so much speculation on what is essentially a nice picture of a couple of dogs.

 

Rex

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[Bob Ross]

Hi guys,

 

I can fix it too, but it is time consuming, and I would much rather understand why it suddenly started doing this. By the way Rex, I always, and only shoot RAW. Do you also like blacks a bit magenta? Each to his own, I suppose.

 

Someone suggested a possible issue with the SD card, so I switched cards and used the camera this morning , and most of those images were OK.

 

Vinay, I don’t remember the color of the boat - I just saw these guys and snapped them quickly. Maybe like HC says, we are simply looking at the infamous M8 color balance - but then again, both times when this happened to me I was using a specific balance, daylight yesterday, and before that, the shadow setting.

 

I’ll post some normal M8 files from a few days ago - the color is nice there. in fact I was shooting the Noctilux on the M8 and the Canon 50 f1.2 on the 1Ds2, and I much preferred the M8 image color and look.

Hi Bill,

I have seen this yellow cast when using "shadow" WB. I use it when I am shooting landscape, but other subjects don't respond like foliage. When you open the image in C1, what Kelvin number shows? Your comment above, "...most of those images were OK.", indicates that you are getting inconsistancy. If the WB Kelvin in C1 is wandering when you have apreset WB set, then something could be wrong in the camera.

I'll stick with the WB over IR, because it fixed with one color balance correction and I don't see any of the usual IR signs....blue pack between dogs, rope (nylon?) or the black under the person's arm (clothing?) The chrome of the steering wheel will also show some signs of IR somewhere. You could check the presets for WB against a manual WB to see what is going on. BTW, neat picture.

Bob