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02-16-2008, 02:41 AM   #1
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Reds frequently blown with K10D?

I've been working on a project for a couple of years and have a year to go on it.
It involves shooting the construction of a ring road around the western outskirts of the city where I live.
As a consequence I tend to frequently have bright orange safety barrier meshin the pictures.

I'm finding a high percentage of pics which are otherwise correctly exposed have the reds/oranges driven into saturation and the clipping indicator is heavily on in Adobe Camera RAW when I come to process them. reducing the overall exposure doesn't seem to help.
To get the reds out of clipping makes the rest of the pic far too dark.
I did not seem to get this problem with the KM A2 that I used for a couple of years on the project.

Even red-browns are prone to clipping when everything else is well exposed.
Is anyone else noticing this and has anyone a developed a good work-around or remedy?

02-16-2008, 04:17 AM   #2
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Some steps that might help, applied while in ACR:
- turn down the color temperature in ACR (from Y towards B)
- increase recovery
- reduce brightness
- choose AdobeRGB1998 as the output profile
- reduce vibrance and/or saturation
When all of the above produce a too dark copy, open the same raw file again in ACR but this time adjust for the areas that got too dark first time, disregarding the clipping warnings. Don't alter the cropping in any way. In photoshop, drag the lighter copy exactly on top of the darker or the other way around.
You have a two-layer picture where you can pick the best parts of both layers using the eraser tool on the top layer, preferably with a fairly large and soft brush. When the areas look OK, merge down.
Mathias
02-16-2008, 05:42 AM   #3
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What JPEG settings are you using in-camera? Even when you're shooting RAW these affect the histograms and the blown highlights warning.
02-16-2008, 06:04 AM   #4
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I believe the Red channel clips earlier than the others. I have found the same thing while taking a picture of my kid with a red Elmo doll. The reds contained very little detail while the rest of the picture was underexposed. I've seen this problem posted before.

- Andrew

02-16-2008, 08:09 AM   #5
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For JPGs with my K10D I set the WB to 5500 K to make sure the RGB channels are all at unity gain. (and best dynamic range for all channels!) If you shoot in overcast conditions with Auto WB the Red channel will get boosted and will probably clip depending on the scene elements.

For RAW I do not attempt to correct WB in ACR , but just tweak exposure controls if necessary. I never use AUTO. I use selective Hue and Saturation & Level controls in CS3 to straighten things out as required.

You can also help avoid blowing out the red (or blue) channel by keeping the camera set to 5500 K and then use a filter on the lens to correct the color temperature. I think many pros prefer this method.

The following filters are useful for overcast days or shooting in open shade ...

81A pale orange Warming filter to increase the color temperature slightly
81B pale orange Warming filter, slightly stronger than 81A. The opposite of 82B.
81C pale orange Warming filter, slightly stronger than 81B, opposite of 82C.
81D pale orange Warming filter, slightly stronger than 81C.
81EF pale orange Warming filter, stronger than 81D.

I too still have my A2.

Do you have any examples you could post of your problem images?
02-16-2008, 05:12 PM   #6
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FWIW, friend w/ a Nikon D80 complains about the red channel blowing earlier as well. The difference is w/ the K10D, we have histograms of the 3 channels while the D80 only has a unified single histogram so it's harder for him to detect.
I think it's a "feature" of the Sony CCD sensor...

Learn to use the 3 histogram mode while shooting...
02-16-2008, 06:13 PM   #7
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I have seen a lot of threads complaining about this, and the one thing I have noticed since I began reading these threads is that red, when you look at it even with your eyes, is MUCH brighter than other colors. The eye is most senstive to yellow, close to the natural color of sodium lights, but yellow does not jump out at you like red does.

After looking around at what I see, I think the camera faithfully reproduces what you see, reds are really red.
02-16-2008, 06:25 PM   #8
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Check out this thread:

https://www.pentaxforums.com/forums/pentax-dslr-discussion/16700-question-abo...s-burning.html

I'll respectfully disagree with Lowell. The camera doesn't have the dynamic range to capture what your eye can see, but you can work within the limitations of the technology if you understand colour theory and photoshop...

02-16-2008, 06:38 PM   #9
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QuoteOriginally posted by d.bradley Quote
Check out this thread:
I'll respectfully disagree with Lowell. The camera doesn't have the dynamic range to capture what your eye can see, but you can work within the limitations of the technology if you understand colour theory and photoshop...
That's my point, reds are really bright, and since the camera does not have the same dynamic range as your eye, they can burn out
02-16-2008, 06:49 PM   #10
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Thanks for all the informative replies.
It's nice to know it's not just me experiencing this :-)

I've been shooting raw.
I've been using AWB, I see from the thread that d.bradley referred to that the red channel is often heavily boosted by the white balance corrections.
I'll try setting a 5500k white balance.

The jpeg settings in camera would be the defaults.
Will check out the "three histogram" mode.

I'll find an example or two tonight and make some sample pics to show you,
as I've been thinking about I've remembered that the worst examples have been the safety orange pennants that they string across road/track closures, they're even worse than the mesh stuff.
02-16-2008, 06:54 PM   #11
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Anyway if you want to restore lost detail, try this:

1. Go to the Channel tab in PS Select the green channel (image will be b&w)
2. Slect all and copy
3. Turn on all RGB channels and paste the b&w image over the original.
4. Go to your layer properties and select "Blend-->Hard Light"
5. Create a layer mask, and keep only the area you want to be affected.
6. Adjust the final hue if necessary using a colour adjustment layer

Voila, you have recovered texture details from your blown out channel.
02-16-2008, 07:33 PM   #12
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Thanks d.bradley, I plan to try that green channel technique tonight.
02-17-2008, 02:32 AM   #13
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Here is a sample of the problem, screencap from ACR.
02-17-2008, 06:08 AM   #14
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Normal, that's the weak spot of digital cameras. However, the K10D is a bit more vulnerable on this, at least from my experience the K100D is a little bit better.


QuoteOriginally posted by pw-pix Quote
I've been working on a project for a couple of years and have a year to go on it.
It involves shooting the construction of a ring road around the western outskirts of the city where I live.
As a consequence I tend to frequently have bright orange safety barrier meshin the pictures.

I'm finding a high percentage of pics which are otherwise correctly exposed have the reds/oranges driven into saturation and the clipping indicator is heavily on in Adobe Camera RAW when I come to process them. reducing the overall exposure doesn't seem to help.
To get the reds out of clipping makes the rest of the pic far too dark.
I did not seem to get this problem with the KM A2 that I used for a couple of years on the project.

Even red-browns are prone to clipping when everything else is well exposed.
Is anyone else noticing this and has anyone a developed a good work-around or remedy?
02-17-2008, 03:38 PM   #15
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QuoteOriginally posted by pw-pix Quote
Here is a sample of the problem, screencap from ACR.
I find that happens in JPEG mode when set to Bright and with Saturation at 0 or higher -- not nearly as badly with Saturation at -1.
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