UniWB on the EOS 6D?

With my 5D2, getting UniWB was pretty simple. Overexpose a raw file into pure white by 5+ stops. Then use it as custom WB. It worked like a charm.

Will the same procedure calibrate an accurate UniWB for the EOS 6D as well?

I have no idea what you are talking about. What is UniWB? What is it good for?

I actually would shoot the body cap and use that as my custom wb frame, when doing uniwb. Have you tried that? Basically we found that a black frame would serve the same effect.

Yashica, not sure if this post will help, but there are large full threads describing the virtues of setting your custom WB this way to allow you to see a more true histogram of the image at the raw level and thus you can control your exposure to a greater level, and you then just reset the wb in the raw afterwards. Without doing this, your histograms on the camera's LCD will NEVER be trustworthy and truly represent your raw data. If the histogram displayed was really from the raw data and not the JPG, I am not sure uniwb has alot of value.

https://photography-on-the.net …hp?p=15113441&p​ostcount=2
http://www.rawdigger.c​om/houtouse/beware-histogram

Shooting a black frame (which isn't quite as accurate as doing the channel blowout method), is easier and it basically offsets the JPG overeager histogram to more closely represent the raw data histogram. Kinda like micro AF adjustments for lenses, but a micro adjustment for the histograms.

Here is one I did in my 7D review. https://photography-on-the.net …p?p=13426750&po​stcount=72

TS,
Thanks. Now I know what it is. Is this something one would use in specific situations? On first glance, it appears like a good way to blowout at least one channel completely. How do you recover from that? Or perhaps I am misunderstanding the purpose.
TS <== (real initials, ironic here, aren't they?)

YashicaFX2 wrote in post #16433520
TS,
Thanks. Now I know what it is. Is this something one would use in specific situations? On first glance, it appears like a good way to blowout at least one channel completely. How do you recover from that? Or perhaps I am misunderstanding the purpose.
TS <== (real initials, ironic here, aren't they?)

No, it is a good way to know when the green channel is just short of clipping.Because the sensor is more sensitive to green, in any panchromatic light if the green channel is not clipped, the other two will not be clipped. Of course if the green is very close to clipping, when you apply a conventional WB in the Raw converter it may (in fact probably) cause the red or blue to clip, but because you are using Raw data you can prevent this by controlling the channels independently.

I use the Uni-WB all the time and have always used the black frame method until I started using Magic Lantern which allows you to set the WB multipliers, so I simply set them to 1.0.

OK, thanks for trying, but this is a bit over my head. I'll just continue using a grey card, when I need one. Often I just use a white dinner napkin, or whatever is handy. That works well enough for me.

YashicaFX2 wrote in post #16434751
OK, thanks for trying, but this is a bit over my head. I'll just continue using a grey card, when I need one. Often I just use a white dinner napkin, or whatever is handy. That works well enough for me.

Yes, Uni-WB is really for the person who is trying to push his camera to maximum performance - max DR, minimum noise, max IQ - by shooting Raw and exposing to the right. If that's not where you are, use the conventional methods and enjoy your photography.

tzalman wrote in post #16434865
Uni-WB is really for the person who is trying to push his camera to maximum performance - max DR, minimum noise, max IQ - by shooting Raw and exposing to the right.

In other words, UnibWB is for those of us who are using cameras without Sony's incredible sensors.

Seriously, if I was shooting with a camera that has 14 stops of DR like the D800 or A7r... then I wouldn't even bother with ETTR and UniWB and HDR and all that nonsense.

stargazer78 wrote in post #16435864
In other words, UnibWB is for those of us who are using cameras without Sony's incredible sensors.

Seriously, if I was shooting with a camera that has 14 stops of DR like the D800 or A7r... then I wouldn't even bother with ETTR and UniWB and HDR and all that nonsense.

Nope, uniWB is to set your histogram to more properly reflect your exposure of the raw data, instead of the "exaggerated" histogram you get now from the JPG data. Unless the Sony shows the histogram of the raw and not the processed JPG, the same thing would work with that, I would think.

TeamSpeed wrote in post #16436087
Nope, uniWB is to set your histogram to more properly reflect your exposure of the raw data, instead of the "exaggerated" histogram you get now from the JPG data. Unless the Sony shows the histogram of the raw and not the processed JPG, the same thing would work with that, I would think.

You've completely missed my point.

If I had 14 stops of DR, I wouldn't have to put so much effort into squeezing every bit of information into Canon's 11-stop dynamic range. And I wouldn't try to push ETTR so aggressively if I could pull out noise-free details from underexposed shadows.

stargazer78 wrote in post #16436182
You've completely missed my point.

If I had 14 stops of DR, I wouldn't have to put so much effort into squeezing every bit of information into Canon's 11-stop dynamic range. And I wouldn't try to push ETTR so aggressively if I could pull out noise-free details from underexposed shadows.

No, I didn't miss your point, I was pointing out this uniWB is basically very easy to do, and ETTR using a better histogram is also quite easy. There is virtually no effort.

And for what you shoot, what percentage really needs that? What do you shoot now that you need the extra 3 stops?

People like to be a bit over exaggerated in their needs and how hard things are now with what they have.

stargazer78 wrote in post #16436182
You've completely missed my point.

If I had 14 stops of DR, I wouldn't have to put so much effort into squeezing every bit of information into Canon's 11-stop dynamic range. And I wouldn't try to push ETTR so aggressively if I could pull out noise-free details from underexposed shadows.

I would.

I would still want to get every bit of those 14 stops. But that's me, always pushing the envelope, never satisfied, always wanting more. Remember Sisyphus? Ever wonder why after the twentieth time the stone rolled back down he didn't just say, "Screw this," and walk away? Nowadays we call it OCD.

TeamSpeed wrote in post #16436211
No, I didn't miss your point, I was pointing out this uniWB is basically very easy to do, and ETTR using a better histogram is also quite easy. There is virtually no effort.

And the geniuses who contribute to Magic Lantern, especially a1ex the alpha dog, have made it even easier with their Auto ETTR.

Some of the recent work of ML looks very interesting. Just imagine the possiblities from a very pixel dense camera (around the 40Mpix mark say) with dual ISO? I guess the big question is will Canon themselves ever take this up and offer it as a factory option? Sometimes it seems as if the engineers at the two biggest makers are still stuck in the film age, rather than fully embracing the possiblities that the electronic sensor can/could supply.

Alan

Yes, seven years after putting Live View into the cameras they still have not given any consideration to using the live Raw feed from the sensor as anything other than a waystation on the road to a processed RGB image because they are locked into the view that it is what almost all their buyers want. I wonder when they will realize that that market is rapidly disappearing as the potential buyers are all photographing with their phones.