D7100 1.3x crop in sensor vs Crop in Software?

Jim,

I'm curious on your thoughts that in crop mode the D7100 might have the same DR as a D300. If I have a perfectly smooth gradient from pure black to pure white and take a photo using the full sensor mode I'd get a picture with the maximum DR the sensor can give.



Hypothetical D7100, full sensor

Now standing in the same spot I put the camera into crop mode and take another picture.

Hypothetical D7100, crop mode

I can see where it looks like I've clipped the very dark and very light portion of the gradient. But instead of standing in the same location to take the cropped mode shot what if I backed up a bit to put the full gradient within the 1.3 crop-mode field of view.

Hypothetical D7100, crop mode with gradient completely within field of view

Wouldn't I then capture the full dynamic range of the gradient? Why would the DR of this shot differ from the first shot? If I stood in the original location and zoomed in a bit to put the framing of the portion of the gradient viewed equal to the portion of the gradient seen by the crop mode in the second shot, wouldn't this then have the same DR as the second shot, done in crop mode?

Or are you saying that when using a 6000 x 4000 pixel capture you'll inherently get more dynamic range than when using only 4800 x 3200 pixels of the exact same sensor? I understand that the individual steps from pure black to pure white will be coarser with fewer pixels to spread out over the gradient, but wouldn't I get the same pure black to pure white range?

Can't quite get my brain wrapped around the concepts ...

Not picking nits here, looking for serious answers.

Hmm, for some reason after hitting the "Post" button not all the jpg's show up.  Here's links to the three examples:

http://www.texasmothman.com/dpreview/D7100a.jpg

http://www.texasmothman.com/dpreview/D7100b.jpg

http://www.texasmothman.com/dpreview/D7100c.jpg

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Mothman13
www.texasmothman.com