Digital Light & Color

I thought I got it, but apparently I don't... The idea of UniWB is to set WB so that the RAW RGB 'channels' multipliers are all 1. This way the in-camera R,G,and B histograms (not the luminance) should be able to show those photosites that are actually maxed out in RAW (either R,G or B are clipped)....

It's Canon S95 - a 10Mp, 1/1.7" sensor camera. Sean's lens/sensor diffraction model predicting at what apertures it may become a visible nuisance (the Java calculator on the second page of the article quoted before), computes it as around f4. This is amazingly close to my informal observations....

Trying to test the lens sharpness as a function of aperture, I set the camera on a tripod and shoot the scene with lots of details and textures at base ISO and f2, f2.8, f4, f5.6 and f8. The details get consistently and progressively more blurred as the aperture gets smaller (i.e. they seem the shar...

What's the semantic difference between 'luminance' and 'luminosity'?

The issue, I think, is what's blinking? In the cameras I checked, only the pure-white pixels are marked as overexposed - those that have 1 or 2 channels blown would not be marked. This is consistent with the Luminosity histogram. Also, unless the WB is set to UniWB, both the histogram and the overex...

I'm still learning, but I think this is all about interpreting the histograms. There are at least two issues: 1) the in-camera life histogram likely shows the luminosity (mine does) - a weighted average of gamma-transformed RGB values. It shows clipping when all 3 RGB channels are saturated (pure wh...

Just one more article on the UniWB topic. It's all theoretically interesting, but is it of practical value: is equating RAW channel multipliers going to be such a panacea for optimizing the exposure when shooting RAW? Do people have any experience with tweaking RAW channel multipliers? Cheers! http:...

Here is a post in similar vein and Sean's answer/addendum to his article on histograms. I experimented and I confirm that at least Canons I have access to show Luminosity histogram, if only one histogram is shown. Clipped channels won't show as clipped, only pure black/pure white will. One way of lo...

I've been trying to figure out what exactly the in-camera histograms are showing: it looks like most newer cameras show the Luminosity histogram and then, possibly, 3 individual RGB channels for developed JPG image. I'm trying to understand the UniWB concept better, hence the interest. Would it be u...

Forgot to ask (and I don't seem to be able to find appropriate reference): when adjusting WB in RAW processors, say in 'As Shot' option, the multipliers reported in EXIF must be converted to Colour Temperature and Tint couple somehow (and vice versa: the Colour Temperature and Tint set by the user h...