Morning Star Loc: West coast, North of the 49th N.

Who said I don't understand the principles of light?
What I said (in different words) was that I had problems with the representation of light in a graphic. I thought I also let it come through that I finally do understand that graphic.

floral43

A histogram is a representation of those 256 tones of gray, The more you know about them the less likely you are to become confused.

Apaflo Loc: Anchorage, Alaska

That's true. But what you posted was extremely confused...

floral43

Your statement that you just discovered how to use a histogram in your camera, suggest to me that you need a better understanding of light.
Because the first thing you should have learned before ever taking a picture was the use of a histogram in your camera.

lighthouse Loc: No Fixed Abode

Stop trying to pretend its more complicated than it is.
Because it just isn't.

floral43

Complexity is the rearrangement of simplicity.
To say that photography hasn't become complicated is not a wise statement, just go to a book store and you will find thousands of books on the subject. And many the hogs are reading them.

Morning Star Loc: West coast, North of the 49th N.

PLEASE !!!! go back to my initial post in this thread: I DID NOT say that I just discovered how to use a histogram in my camera, I said " I've just discovered that I can use a histogram in-camera before I take the picture."
I have used the histogram plenty of times after I have taken a photo and playing it back in-camera.
I have just discovered that I can see a histogram for a photo that I still want to take.

When I started taking photos there was no such thing as an in-camera histogram, so no reason to learn that. The first thing I ever learned was the relationship between sun, overcast, aperture and exposure. The ISO number didn't come into the equation for me at that time, as it was my Dad who decided what Din number film went into the camera, usually 21 or 24. He also loaded the film, and took it out when it was full.

Gradually Dad taught me other bits and pieces about photography, and when he took a group of his students to Gevaert in Belgium to learn about colour photography, he came back with three colour slides: a red one, a blue one and a green one. I still have them! (Yes, I'm implying that he also taught me about light).

jcboy3

Do a search of UHH for previous discussions of histogram. Most cameras do not properly compute a histogram and will not indicate overexposure in red or blue channels.

I wrote about this in a previous post:

"The primary issue with using live view histograms is that they do not uniformly represent the different color channels; they are heavily weighted towards the green channel. Thus, they will not indicate blown highlights in the red or blue channels.

In fact, some camera models only show the green channel in the histogram; this was common with early Nikons, for example.

Easy to test; take an over-exposed image of a red sheet of paper.

Set to manual, wide open aperture, and decrease shutter speed. In live view, watch the histogram and look at the image. When you hit over-exposure, the red image will start to shift to yellow because the red channel is maxed out and the blue and green channels keep increasing. Generallly, the histogram will still show a correct exposure.

After taking the exposure, look at the color and combined histograms, and see that the red channel indicates over-exposure but the combined histogram is fine.

If your camera does not do this, but actually shows overexposure in the histogram when the red channel is overexposed, then the histogram will be useful for accurate exposure determination. Otherwise, the histogram is not accurate for exposure determination."

I have an Olympus E-M1, and it suffers from this problem. I never use the histogram because it clutters the display and suffers from this problem. I find the highlight/shadow overlay is a quicker to see indicator of overexposure, but it has the same issue of missing red/blue channel overexposure. In particular, if there is a preponderance of red then I dial down the exposure or bracket if there is time. If in doubt, check the full color histogram in playback mode. The red/blue channel histograms will indicate significant overexposure.

See http://www.kenrockwell.com/tech/yrgb.htm for an explanation of the green channel only issue with some histograms.

floral43

It's my misunderstanding of what i read, I just thought i shed some light on the subject, after all that's what the site should be about information,

floral43

That is why we calibrate cameras by taking the proper white balance at the right time of day or indoors. a bayer pattern is green heavy because of nature.

Morning Star Loc: West coast, North of the 49th N.

You may have shed some light on the subject, but it was not the light I was looking for. In fact, I was not looking for anything, I did not ask any questions.
I just shared something that I had just discovered. A toy inside a toy. I don't know how helpful this toy will be for me. In a few weeks from now, I may decide it is the best thing since sliced bread, or I may turn it off again and never look back. My experience, my choice.
There are other toys inside this new toy, but after this thread I don't know if I'll be sharing about them, even if I do get excited about finding them.
I appreciate Hoggers replying to my posts, but I appreciate even more if they read my post and know what I said before responding.
You should understand by now that I really know a bit more about light than you gave me credit for.
In any case, let this be the end of this thread.

lighthouse Loc: No Fixed Abode

Esther, do not let anyones' negativity get to you.
I want to know about the next new toy you find within the toy.
It might be something that is useful to me.

jcboy3

Nonsense.

White balance is used to correct for color temperature of a light source, not the color balance of the objects in the image. And the fact that the Bayer filter has two green for each red and blue filter is not a good reason for most white histograms to ignore red and blue channels.

The point I was making is that histograms are generally not implemented to include data from all channels, and so do not indicate when clipping will occur in the excluded channels.

SIDEBAR:

The Bayer filter has two green filters (peak at 545nm) for each red filter (peak at 615nm) and blue filter (peak at 460nm).

Green is the color for which the human eye is most sensitive, with peak sensitivity around 550nm and a 50% range from 510nm to 610nm. So two green filters provides increased signal and reduced noise in that region.

On the other hand, alternative patterns with cyan, magenta and yellow filters provide better light absorption (improved quantum efficiency) and would be much better for digital cameras. But alternative dyes were much more expensive, so RGB dyes were used. Why this continues to be the case is not clear.

FINAL NOTE:

Stop berating the OP.

Morning Star Loc: West coast, North of the 49th N.

You got it!
But man, there's a lot of new stuff about this camera. And I thought there was a lot to learn when I got my E-5 ;-)

floral43

Regarding White bal in your statement, How can you make such a statement, White is the summation of all color! when white is truly white the colors are correct (no color cast) that's why you set a white bal.to attain correct colors.
Don't rely on The kalvin scale, because the ( reflective light) brightest white piece of paper when photographed if measured on the scale can be no greater than 5000 K. that's white as the camera sees it.
your term Balance is misleading,
The sensor doesn't see color it sees gray scales 256 of them (histogram) color is interpolated in fact you can prove this in photoshop, go to channels on the pallet turn off red and green Blue will be gray do the same with the other channels they will reflect gray.
Your explanation of the bayer pattern is brilliant.
I didn't join the hog to berate any hog, Sharing information is a way of learning whether it be right or wrong that is why we debate issues, if i am proven wrong so be it, i just learned something new. Volla i am grate full.
Don't let your EGO get in the way.