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Occasional Contributor
Posts: 11
Registered: ‎03-27-2019

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

yes
VIP
Posts: 8,041
Registered: ‎08-13-2015

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


@VektorCRO wrote:
yes

Hmm.  I do not think the 5D2 has anti-flicker settings.  Use a tripod and take a “long” exposure of the LED lights.  I would say use a shutter of 1/10, or slower.  Let’s see what the colors look like then.  I still think that a CPL filter could be beneficial.

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"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Esteemed Contributor
Posts: 3,308
Registered: ‎02-17-2016

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

Have you tried in-camera HDR? Have you tried RAW?

 

At some point you need to *do* something rather than just discussing it here.

Occasional Contributor
Posts: 11
Registered: ‎03-27-2019

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

belive me I tried. Bought a CPL and UV filter, nothing. Tried underexposing with CPL and still the same. Did recently a video with a new car. Still purple. Starting to think it is sensor issue. Not that it is broken, rather it is the problem with new LED-s.

 

IMG_2369.JPG

Esteemed Contributor
Posts: 3,807
Registered: ‎06-11-2013

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

I'm still seeing color channels clipping.  The lights are quite bright compared to the exposure needed for the rest of the vehicle.

 

You may have have to use some HDR.

 

See:

 

Screen Shot 2019-04-08 at 1.05.54 PM.png

 

I'm sampling the pixels in the tail light and both the blue and red channels are clipped.  

 

When I do the vehicle to the left (where the tail-lights look more red), the red channel is clipped, but not the blue or green. 

 

Either way, this changes the hue.  For something to look properly "red", you should see a strong red value (but not clipped) and a low blue and green value.  

 

When your red channel is 255 (which is clipped .. that's the max value of an 8-bit JPEG), but your blue channel is also 255 (also clipped) you now have equal amounts of red & blue.  Red + Blue = Violet.   The "green" channel brightens up the violet to something that looks a bit more magenta.

 

Basically this means your tail lights are *really* bright compared to the rest of the vehicle. The exposure that nicely exposes the car is completley over-exposing the lights.

 

If you spot meter the tail-light (even if that means walking the camera lens up to the tail-light so you are just inches away) and take a meter reading.  That would be a "middle" exposure for the tail-light (for a camera, that's usually 12%).  The tail light should be bright (just not blown out) -- so you can shoot a few stops above that exposure, just make sure you check the RGB values to verify that no channel is blown out (nothing is reading 255).

 

From there you can shoot an additional shot metered for the whole car (you'd want the camera on a tripod so nothing moves) and then merge those via Photoshop (or any HDR software.)

 

What you are doing is a bit tricky ... so don't feel bad that you've been having a hard time with it.  

 

Other things you can do is put a circular polarizer on the lens and rotate it while watching the reflections on the car.  Rotating a polarizer will dial the reflections up or down.  I usually don't like to *completely* kill the reflections (or the card wont look shiny) but I try to tame them down so they aren't a distraction.

 

Tim Campbell
5D III, 5D IV, 60Da
Esteemed Contributor
Posts: 3,308
Registered: ‎02-17-2016

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

He clearly does not want a solution that involves *work*. I mentioned HDR in the 4th post.

 

He was hoping for us to tell him about a menu item for "Make Purple Tail Lights Red".

Occasional Contributor
Posts: 11
Registered: ‎03-27-2019

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

No need for hostility. The solution you mentioned I dont have in my camera (5d MkII). The point of this forum to talk and solve problems so when it happens to someone else, here is a solution. So chill.
Esteemed Contributor
Posts: 4,952
Registered: ‎06-25-2014

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


@TCampbell wrote:

I'm still seeing color channels clipping.  The lights are quite bright compared to the exposure needed for the rest of the vehicle.

 

You may have have to use some HDR.

 

See:

 

Screen Shot 2019-04-08 at 1.05.54 PM.png

 

I'm sampling the pixels in the tail light and both the blue and red channels are clipped.  

 

When I do the vehicle to the left (where the tail-lights look more red), the red channel is clipped, but not the blue or green. 

 

Either way, this changes the hue.  For something to look properly "red", you should see a strong red value (but not clipped) and a low blue and green value.  

 

When your red channel is 255 (which is clipped .. that's the max value of an 8-bit JPEG), but your blue channel is also 255 (also clipped) you now have equal amounts of red & blue.  Red + Blue = Violet.   The "green" channel brightens up the violet to something that looks a bit more magenta.

 

Basically this means your tail lights are *really* bright compared to the rest of the vehicle. The exposure that nicely exposes the car is completley over-exposing the lights.

 

If you spot meter the tail-light (even if that means walking the camera lens up to the tail-light so you are just inches away) and take a meter reading.  That would be a "middle" exposure for the tail-light (for a camera, that's usually 12%).  The tail light should be bright (just not blown out) -- so you can shoot a few stops above that exposure, just make sure you check the RGB values to verify that no channel is blown out (nothing is reading 255).

 

From there you can shoot an additional shot metered for the whole car (you'd want the camera on a tripod so nothing moves) and then merge those via Photoshop (or any HDR software.)

 

What you are doing is a bit tricky ... so don't feel bad that you've been having a hard time with it.  

 

Other things you can do is put a circular polarizer on the lens and rotate it while watching the reflections on the car.  Rotating a polarizer will dial the reflections up or down.  I usually don't like to *completely* kill the reflections (or the card wont look shiny) but I try to tame them down so they aren't a distraction.

 


I'm pretty sure that DPP allows you to dminish the blue and/or green channels without affecting the red. I'd be really surprised if Lightroom/Photoshop didn't let you do so as well. In an image as dark as this one, the rest of the car wouldn't know the difference.

Bob
Philadelphia, Pennsylvania USA
Esteemed Contributor
Posts: 3,807
Registered: ‎06-11-2013

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


@RobertTheFat wrote:

I'm pretty sure that DPP allows you to dminish the blue and/or green channels without affecting the red. I'd be really surprised if Lightroom/Photoshop didn't let you do so as well. In an image as dark as this one, the rest of the car wouldn't know the difference.


Bob, can you do that in DPP and localize the adjustment to *just* the tail-light.  You wouldn't want to bring down the blue channel globally or you'd change the color of the car and the whole scene.

 

Are these lights just a reflection of a flash or are the lights switched on?

 

Since the car isn't moving, you wouldn' tneed any extra lighting ... just use a tripod and you can let the exposure run as long as you want.  I think many of us have taken shots in near darkness and had it look like bright lighting by leaving the shutter open long enough to collect an adequate exposure.  It's especially easy to do since the subject isn't in motion.

 

Tim Campbell
5D III, 5D IV, 60Da
Occasional Contributor
Posts: 11
Registered: ‎03-27-2019

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

Thing is, I do around 30 cars daily. Each car 20 photos. Using extra lights or tripod is not possible with time requierments.
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