Solution to blown out reds?

[EricBowles]

If you find the highest nonblinkie exposure that, of course, is safe, but depending on which picture control is set you can safely add 2/3 stops to that for raw but none to jpg.

One thing to keep in mind is the ability to recover blinking highlights varies depending on your software and which specific camera you are using. Blinking highlights are based on the embedded JPEG - which means your camera settings affect blinkies. In addition, your picture control choice will affect blinkies with Landscape and Vivid having the greatest impact and Flat having the least. In addition, sometimes a glance at an image may show no blinkies, but zooming in for higher magnification may reveal blinkies in the brightest areas.

I like to have a little bit of blinkies showing with a Neutral knowing that I can use sliders to make easy adjustments to resolve any blinkies. Also keep in mind that Nikon's blinkies are a warning that you may lose highlights, not a notification that highlights are lost.

 

[bleirer]

One thing to keep in mind is the ability to recover blinking highlights varies depending on your software and which specific camera you are using. Blinking highlights are based on the embedded JPEG - which means your camera settings affect blinkies. In addition, your picture control choice will affect blinkies with Landscape and Vivid having the greatest impact and Flat having the least. In addition, sometimes a glance at an image may show no blinkies, but zooming in for higher magnification may reveal blinkies in the brightest areas.

I like to have a little bit of blinkies showing with a Neutral knowing that I can use sliders to make easy adjustments to resolve any blinkies. Also keep in mind that Nikon's blinkies are a warning that you may lose highlights, not a notification that highlights are lost.

I agree about the impact of the picture controls and that the histogram and preview and blinkies are based on the jpeg. I use faithful on my camera. For my own use I went to the bother of shooting a light colored target with no detail then analyzing it in rawdigger. In my case I used a blank white screen on a monitor. First centering the meter and shooting then increasing each exposure in 1/3 stop jumps until the camera was nothing but solid blinkies.

In Rawdigger I could match up what the camera blinkies were doing compared to the actual data. I found I could reliably locate the highest no-blinkie exposure. The next 1/3 stop up the camera showed a few blinkies but there was still plenty of headroom in Rawdigger. At +2/3 stops there was still room but at +1 a channel clipped.

So as a reliable field technique when the light and subject are steady I don't need a meter per se. I can simply find the highest non-blinkie exposure (ignoring small areas I deem unimportant) with some test shots and know I can safely add 2/3 stops without worry even though I'm getting blinkies. For fluid situations I also have developed a feel for what the right edge of the 3 color histogram is doing at non-blinkie, +1/3 and +2/3 but I don't push it up the wall even though I could, since modern cameras have a huge well of dynamic range.

 

[EricBowles]

I agree about the impact of the picture controls and that the histogram and preview and blinkies are based on the jpeg. I use faithful on my camera. For my own use I went to the bother of shooting a light colored target with no detail then analyzing it in rawdigger. In my case I used a blank white screen on a monitor. First centering the meter and shooting then increasing each exposure in 1/3 stop jumps until the camera was nothing but solid blinkies.

In Rawdigger I could match up what the camera blinkies were doing compared to the actual data. I found I could reliably locate the highest no-blinkie exposure. The next 1/3 stop up the camera showed a few blinkies but there was still plenty of headroom in Rawdigger. At +2/3 stops there was still room but at +1 a channel clipped.

So as a reliable field technique when the light and subject are steady I don't need a meter per se. I can simply find the highest non-blinkie exposure (ignoring small areas I deem unimportant) with some test shots and know I can safely add 2/3 stops without worry even though I'm getting blinkies. For fluid situations I also have developed a feel for what the right edge of the 3 color histogram is doing at non-blinkie, +1/3 and +2/3 but I don't push it up the wall even though I could, since modern cameras have a huge well of dynamic range.

Hi Bill - which specific camera is that? Is it a Sony?

Arthur Morris told me the Sony has the most headroom above a blinkies (your 2/3 stop sounds about right) and the Canon RAW files have the least (less than 1/4 stop). Nikon is in between. None of this affects a proper exposure, but he believes it means you have to be more conservative using Canon blinkies and more aggressive with Sony A1 blinkies. It's simply a matter of how you use the blinkies in in camera that varies. Thus the comment that each camera has it's own level of blinkies that produces the right exposure (and camera settings for the picture control still applies).

 

[bleirer]

So thinking about it in terms of fundamentals from my layperson point of view, I think what happens is that each individual pixel/photosite on the sensor is filtered to respond to only one color. Either red or green or blue. The brighter the scene or the greater the exposure the camera stores a higher number for that pixel up to the max the camera bit depth allows. Later the raw converter uses that value and the values of the surrounding pixels to guess at the RGB values that make up the color for that pixel. If a red pixel hits its maximum before the surrounding green and blue pixels do then the software is still trying to construct the color for that pixel, but red areas will look detail-less since they are all at the same maximum value and so no variation to show texture or nuance. And areas where that blown R is a big part of another color will look funky.

Bottom line as mentioned, you need a less bright scene as in adding shade or a diffuser, or a combination of shade and reflectors, or you have to reduce overall exposure to a level where the red is not stuck up at the maximum value.

 

[bleirer]

Hi Bill - which specific camera is that? Is it a Sony?

Arthur Morris told me the Sony has the most headroom above a blinkies (your 2/3 stop sounds about right) and the Canon RAW files have the least (less than 1/4 stop). Nikon is in between. None of this affects a proper exposure, but he believes it means you have to be more conservative using Canon blinkies and more aggressive with Sony A1 blinkies. It's simply a matter of how you use the blinkies in in camera that varies. Thus the comment that each camera has it's own level of blinkies that produces the right exposure (and camera settings for the picture control still applies).

I shoot Canon. I have an R5 now, but even the entry level RP gave the same results. Would be interesting to see what other makers do, but as you say what the blinkie and histogram do depends on the jpeg which depends on the camera settings. I keep mine on faithful which is fairly neutral. I guess the trick is to be consistent and know how the gear responds.

I think with Sony you can set the sensitivity point of the blinkies. Canon doesn't.

 

[jeffnles1]

RE the OP. The red area on the flower is out of focus so the fine detail will be lost anyway. I'm sure this is just one example of the overall problem you're describing however this specific image would be difficult to calibrate due to the soft focus in the red area.

 

[Ado Wolf]

One more thought since you are using Nikon NXStudio. Take the RAW file and look at it in NXStudio. Then change the Picture Control to Neutral (and Standard as well if you want). This will let you see the impact of just changing the picture control which should be your first step. Watch the change in teh histogram as you change Picture Control settings.

Adjust exposure as needed. This will show you the impact of dialing in a change in Exposure Comp when you took the shot. Again - watch the histogram because your monitor or an sRGB view may be more sensitive than the potential gamut in the file. For example laptop only displays 70% of sRGB, so a little area with no detail is okay if the histogram does not show clipping.

Then when editing, don't add contrast unless you can do so without causing blown highlights. In NxStudio you might put control points on the brightest areas of a red flower and pull back exposure, contrast or saturation further.

If these changes don't help, you have overexposed more than you realize. And that simply suggests to watch your exposure very carefully when photographing bright colors in the red family.

That is exactly what I plan on doing this weekend (finally some free time to process photos). Thanks for all the tips

 

[Ado Wolf]

Same as whites, reduce your exposure. Except there are no whites.

I tired that but it did not work.. I still saw a blinker after going down to -1.0 on exposure compensation.. but maybe that wasn’t enough? Hmm..?

 

[Irap]

If your shooting in Raw you can reduce the saturation in the red channel also try bringing down the red luminance in Lightroom, Photoshop, or what ever editing program you use, that often helps.
If you're shooting jpeg you can do similar adjustment in camera.

 

[SandyW]

Personally I don't pay much attention to the blinkies. I use the histogram, and if in doubt double check the individual channel histograms. I don't think the blinkies necessarily account for individual channels. If you want to depend on the blinkies I would continue to experiment with your system like you are doing. On the other hand I don't push hard to the right like some recommend.

 

[bleirer]

Personally I don't pay much attention to the blinkies. I use the histogram, and if in doubt double check the individual channel histograms. I don't think the blinkies necessarily account for individual channels. If you want to depend on the blinkies I would continue to experiment with your system like you are doing. On the other hand I don't push hard to the right like some recommend.

I did some experimenting on my Canon and concluded that blinkies only show when two of the 3 channels are blown. Red flowers are a killer since the red gets blown well ahead of the green or blue but no blinkies until another channel catches up. As you say you have to use the 3 separate color histogram. Nikon has better tools in camera for looking at individual channels, Steve had a video on the topic.

 

[FB101]

@Butlerkid thank you for the link. I will check it.
I didn’t know one can calibrate camera colors
So far I thought it only applied to monitors and screens.

Yes and no. Camera calibration doesn't impact anything in-camera or how you take the pictures. It is a profile that translates the raw data into data displayed on the screen.
It won't do anything for your histogram in camera or blinkies or how the picture looks on the LCD screen. It won't salvage a blown channel either (nothing will)
That said I agree, it is a very powerful tool to insure accurate color reproduction. Investing into a profiling kit is a great investment if you edit raw photos - otherwise it is useless.
In-camera color profiles, WB presets also have zero impact on capture - only on how things get displayed on LCDs or on computer screens.

So to answer your question directly, what can you do to avoid blowing up a channel?
First, set your camera to the most neutral in camera profile you have (flat or neutral) - it doesn't impact how the picture is taken but it impacts the histograms you see and therefore the exposure decisions you make.
Second, if your camera allows (I am pretty sure the D850 does) switch to histogram by channel and utilize that to monitor blown out channels. If it doesn't, you just need to give yourself a bit more margin of safety when you expose to the right to account for the fact that one blown channel may not move the histogram enough to the right on its own to be visible.
Reducing a blown channel is done the exact same way as avoiding complete overexposure (which is nothing more than 3 blown channels) - you need to reduce exposure. That's the only way to avoid blowing a channel at capture time. The other tricks above only help you getting closer to that ideal exposure.

Third, yes, use camera calibration to ensure as accurate a reproduction as possible when you edit the raw file but by then, if the channel is blown, there is nothing you can do to get the details back (you can salvage the image with all the other editing tricks mentioned, but lost information is lost for good at that point).

Hope that helps.