topic Re: Car LED lights are pink/purple, not red in EOS DSLR & Mirrorless Cameras

Car LED lights are pink/purple, not red

VektorCRO — Wed, 27 Mar 2019 19:35:29 GMT

I have a problem where lights (taillights and even inside on car gauge dials, the light is not red but purple. Anyone have any idea what could be the problem? I am using 5d MkII with 17-40, white balance is automatic. I am shooting hundrets of cars and editing one by one is a big job. Thanks for your anwsers in advance.

Re: Car LED lights are pink/purple, not red

kvbarkley — Wed, 27 Mar 2019 19:38:43 GMT

Look at the pixel numbers for those areas. Are you blowing out the red channel? Try with various negative exposure compensations until you are not at 255 in the red channel.

The other thing could be that there is some flickering going on that the camera is picking up. Try a movie to see if you can catch it,

Re: Car LED lights are pink/purple, not red

VektorCRO — Wed, 27 Mar 2019 19:46:28 GMT

Yeah, the lights are blown. Thing is, I dont do a lot of editing on those pics. I edit 200-500 pics daily. If i underexpose them, it is a lot of work in edit. I am currently thinking of buying an R, maybe with new gereration of processor, this is no longer a problem?

Re: Car LED lights are pink/purple, not red

kvbarkley — Wed, 27 Mar 2019 19:56:38 GMT

No, It is all dynamic range, but not dynamic range from the peak to the shadows, but dynamic range from the peak to the proper exposure. I don't think the R has that much more range that would help you. I think that the only thing that can help you automagically is HDR.

Are you shooting in RAW? Then you could create a preset that lowers the highlights a bit, and boosts the exposure, allowing you to underexpose and fix it automatically.

Re: Car LED lights are pink/purple, not red

VektorCRO — Wed, 27 Mar 2019 20:04:10 GMT

I shoot in JPEG at 13 mpx because of the ammount of pics, it makes it easier and faster for export and edit. I will try RAW but think it would slow down even more my workflow. It happens only on these newer cars, older ones dont make these problems. They get blown because they are a lot stronger then before...probably.

Re: Car LED lights are pink/purple, not red

VektorCRO — Wed, 27 Mar 2019 20:07:55 GMT

https://www.youtube.com/watch?v=y970AMAEua4

Here is an exaple of video. 0:24. The reds are blown also but still red...

Re: Car LED lights are pink/purple, not red

kvbarkley — Wed, 27 Mar 2019 20:28:43 GMT

It would not matter if they are blown if they were pure red, it appears they have a lot of blue, which is not blown out, but disproportionally increased. The video must add a lot more compression, implying that they are not blown out at the sensor, but during the JPEG processing.

Re: Car LED lights are pink/purple, not red

VektorCRO — Wed, 27 Mar 2019 20:33:45 GMT

Thanks for your help. I will try a few different settings next time.

Re: Car LED lights are pink/purple, not red

Ray-uk — Thu, 28 Mar 2019 10:24:13 GMT

I don't think it is blown out reds. The red body areas of the car body look alright, what doesn't look right are the dashboard and the lights, bearing in mind that the red parts of the dashboard are not actually direct lighting but fluorescence from the plastic indicators and to get things to show fluorescence you need lighting that is nearer to the violet end of the spectrum.

I think it is just that the lighting in both cases is coming from LEDs that have a high content of near UV lighting in their spectrum and although our eyes cannot see it your camera sensor can.

Re: Car LED lights are pink/purple, not red

kvbarkley — Thu, 28 Mar 2019 13:51:39 GMT

Then why did the video not have the problem?

Most Red LED's do not have much ultraviolet, it is the white LED's that use phosphers.

Re: Car LED lights are pink/purple, not red

Ray-uk — Thu, 28 Mar 2019 14:22:01 GMT

@kvbarkley wrote:
Then why did the video not have the problem?
________________________________________________________________________________________________

Ah ... good point, I hadn't looked at the video

Re: Car LED lights are pink/purple, not red

Waddizzle — Thu, 28 Mar 2019 14:33:29 GMT

I think a CPL filter would very useful here. It would solve the saturation problem with the high intensity, solid state light sources.

Re: Car LED lights are pink/purple, not red

RobertTheFat — Thu, 28 Mar 2019 16:14:41 GMT

@kvbarkley wrote:
Then why did the video not have the problem?

Most Red LED's do not have much ultraviolet, it is the white LED's that use phosphors.

Maybe the video was taken with a UV filter?

Re: Car LED lights are pink/purple, not red

VektorCRO — Thu, 28 Mar 2019 16:29:28 GMT

No, withouth any filter. It is not the same car, 3 years older. Also LED-s. Since the problem is with the new cars, it could be different LED-s, stronger or something.

Re: Car LED lights are pink/purple, not red

Waddizzle — Fri, 29 Mar 2019 06:50:19 GMT

@VektorCRO wrote:
No, withouth any filter. It is not the same car, 3 years older. Also LED-s. Since the problem is with the new cars, it could be different LED-s, stronger or something.

You need a CPL filter.

If you have a CPL filter, then try this short experiment. Hold one up, and look at your LED TV screen, or computer monitor. Now begin to slowly turn the filter ring until you have turned it in a complete circle. Viola! Your problem can be solved.

Re: Car LED lights are pink/purple, not red

Ray-uk — Fri, 29 Mar 2019 10:30:43 GMT

@Waddizzle wrote:
If you have a CPL filter, then try this short experiment. Hold one up, and look at your LED TV screen, or computer monitor. Now begin to slowly turn the filter ring until you have turned it in a complete circle. Viola! Your problem can be solved.

This works with LED TV screens or computer monitor screens because they have an inbuilt polarizing filter, sadly it does not work with direct LED lighting.

Re: Car LED lights are pink/purple, not red

Waddizzle — Sat, 30 Mar 2019 07:26:04 GMT

@Ray-uk wrote:
@Waddizzle wrote:
If you have a CPL filter, then try this short experiment. Hold one up, and look at your LED TV screen, or computer monitor. Now begin to slowly turn the filter ring until you have turned it in a complete circle. Viola! Your problem can be solved.
This works with LED TV screens or computer monitor screens because they have an inbuilt polarizing filter, sadly it does not work with direct LED lighting.

You are probably correct. I thought solid state light sources produced light that was already polarized. Don’t they add filters to TV monitors to “sharpen” the image coming from the emitters?

I understand what you are saying, but I do not see how a CPL would not be a good solution for cutting the glare and intense iight from solid state light sources.

Re: Car LED lights are pink/purple, not red

TCampbell — Sun, 31 Mar 2019 17:38:38 GMT

@kvbarkley wrote:
It would not matter if they are blown if they were pure red, it appears they have a lot of blue, which is not blown out, but disproportionally increased.

This ^^

As I look at the image and inspect the pixels, the "magenta" color (that should be red) shows me the red channel is blown ... but the green and blue channel are not blown. This allowed the camera to continue to collect more "blue" but it was capped at the "red" limit and this resulted in a noticeable hue shift.

Even in the instrument display has this issue. Many of the "white" areas are reading 255, 255, 255. The highlights are blown.

Other comments: I noticed the OP mentions using "automatic white balance". White balance is only applied if shooting and saving as JPEG (it is not applied if saving as RAW but it will record the choice in the meta-data so that post-processing software could apply the setting).

In any case, "automatic" white balance is notorious among photographers because you never quite know what the camera will do. If shooting JPEG, better to set white balance specific to the scene.

ALSO... these appear to be product photos meant to advertise actual products for sale.

I am particularly fussy in "product" photos. My bias is that consumers deserve true color representation and it should be accurate. I have had numerous situations where I ordered a product based on color -- but upon delivery of the product, the color wasn't even remotely close to the online photo.

The only way to do this ... is to use a proper color-managed workflow. This means the color accuracy is calibrated at time of capture and at time of any editing/adjustment. If physical prints were produced, then that would become part of the workflow that also needs to be color-managed.

For product photos ... use a photography gray card and a color-checker (like an X-Rite ColorChecker card). This allows supporting computer software (e.g. Lightroom supports it) to "profile" the color accuracy and adjust the image so that your colors are bang-on accurate (as long as the image data isn't clipped from over-exposure).

Also color-calibrate the computer monitor using a device such as an X-Rite i1 Display, etc. This way you can be sure the colors are accurate on your display and you aren't mis-adjusting color to get it to look correct on your display, but not correct on other displays. (If someone else doesn't have a color calibrated display and they are unhappy about colors, that's on them to correct their own display.)

Re: Car LED lights are pink/purple, not red

VektorCRO — Sun, 31 Mar 2019 20:15:41 GMT

Hers is another example.Left light is purple and right red. Flash is bounced of the celing....

Re: Car LED lights are pink/purple, not red

RobertTheFat — Mon, 01 Apr 2019 00:35:01 GMT

@VektorCRO wrote:
Hers is another example.Left light is purple and right red. Flash is bounced of the celing....

Are the car's lights even turned on?