Originally posted by PentaxPoke When I first read about EDR, I thought it was a way to get more detail in dark areas. In fact it is just the opposite. It is a way of getting more detail in very bright areas by preventing clipping.
Seems to me it does either or both, depending on where you set your exposure. Youa re right that if the was exposure to a place where the highlights were going to clip, this will prevent that - thus giving you more highlight details. But if your exposure is set to a place where the highlights *don't* clip, then the result should be more shadow detail.
Quote: "Expanded Dynamic Range" must have been coined by a marketer, not an engineer. You can't increase the dynamic range of a camera. That is fixed by the physical limitations of the sensor. EDR simply allows you to take an image of a scene that has high dynamic range, and "squeezes" it into the range of the sensor
There's another aspect to the meaning of "dynamic range" that makes the phrase "expanded dynamic range" even more ludicrous in one sense, but also more logical in another. The maximum dynamic range of every single digital camera, every single film, every single painting every painted is exactly the same: it goes from black to white. That is, the physical picture itself goes from black to white. No digital camera can produce a black blacker than the darkest ink used in producing the print, nor a white brighter than paper the image is printed on.
And make no mistake, this is *not* a particularly large dynamic range. It is far smaller than the dynamic range of most real world scenes. Take the blackest object you can find and the whitest object you can find. Put them both in the same (medium intensity) light. Now look around the room and find some shadow areas. Any reasonably dark object - not just black objects - in a shadow is going to be *darker* than that blackest-of-black object in the light. Converse, put the objects in a shadow and look around the better lit areas of the room. Now any reasonably light-colored object - not just white objects - is going to be *brighter* than the whiter-than-white object in the shadow.
What this says is that no matter what light you look at your print in, there will be real world objects that are both darker than the darkest black in your print and brighter than the whitest white. And no camera in the world can change that fact. The dynamic range of the print is from black to white, period. Does matter what the scene being represented was or what camera was used to record the image. The print goes from the black of the the ink to the white of the paper, and that's not a very large range.
In order to be "telling it like it is", a camera would have to look at your blackest and white objects in the same light and make them come out pure black and white on the print. That way, a snapshot of your black and white objects would appear just like the objects themselves when viewed in the same light. And a snapshot of that snapshot would be the same. But as far as I know, *no* camera does that. They *all* compress the dynamic range of the scene so that if the white object comes out white, the black object comes out grey, leaving room for objects in the shadow to come out darker. And if you expose to make the black object truly black, the white object will come out grey, leaving room for objects that are in more direct light to come out brighter. Meaning any snapshot of the black and white objects next to either will be compressed relative to that actual objects. And a picture *of* that snapshot will compress the range even more, and so on.
So what changes from one camera to another is how the real world maps to that range of black to white. If we say one camera has higher dynamic range than another, what we *really* mean is that it is able to take a wider range of values from dark to light and squeeze them into that same print range of black to white. Which is to say, it compresses the dynamic range of the real world to make it fit the fixed black-to-white range of a print. I don't care how many bits you have to represent different *gradients* between black and white in that print - you're not going to get blacker than black or whiter than white in a print.
So it's *already* a misnomer to talk in terms of one camera having higher dynamic range than another. They are *all* identical in the dynamic range they *produce*:. black to white, period. What we really mean is that one camera can take a wider dynamic range in the real world and squeeze it into the black-white range on the print. And the D-range feature does this, too.
So if you accept the ridiculousness of claiming that one camera has higher DR than another but understand nonetheless what is really meant by that, the idea of saying that the D-range feature also increases dynamic range is not more ridiculous.
It's only if you choose to interpret "dynamic range" in terms of the number of discrete values that can be *produced* between white and black that bit depth comes into it - and then, that becomes the one and only determining factor.