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Old August 26th 15, 08:01 AM posted to rec.photo.digital
Sandman
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Posts: 5,467
Default New sensor with unlimited dynamic range

In article , RichA wrote:

Alfred Molon:
http://web.media.mit.edu/~hangzhao/modulo.html
When a pixel fills up, it is automatically emptied. The
camera counts the number of times a pixel is emptied.
Pixels in the darker image areas probably never completely
fill up.

Sandman:
Pretty smart, but the example images didn't really
sell the concept enough. With "unlimited" dynamic range,
you'd think nothing in the image could possibly be
overexposed, but some of the example images, while a lot
better than the normal photos, still looked like they were
blown in areas. Since this "unlimited" dynamic range only
works for highlights, you also need to expose for the darkest
part of the scene. Or, if this technology would find itself
into normal Nikons and Canons, they would automatically
expose for the darkest part of the scene, while everything
else would be blown and then in-camera recovered. Not sure
what the coloring is used for in the example images? I am
assuming we're looking at raw images with a really high bit
rate, and for some reason they are showing those higher
values with funky colors for some reason. Makes me wonder
what kind of post-processing is needed for each photo. The
logical thing to do is to use a high bit depth for the image,
like 16 or 32 bit, but keep "normal" exposure data in the
first 14 bits for example. So instead of 0-2744 in 14bit be
the same range as 0-4096 in 16 bit, the first 0-2744 in 16
bit corresponds to 1 bit data, while the rest is used for the
otherwise overexposed data, which of course requires some
fancy post-processing to even the range out to a normal
image. Or you use a 16 bit readout from the sensor (as per
above), then in-camera re- arrange that to a 14 bit range,
producing a balanced image. -- Sandman

RichA:
This is all fine, so when they will apply similar progress to
display technology?


Sandman:
That's... not the same thing at all. -- Sandman


So what good is it if the camera does it but you can't SEE the
result?


Yes you can. You just didn't understand it. Viewing HDR images doesn't require a
HDR monitor, it's all about compressing the larger dynamic range into a smaller
dynamic range.

Since the human eye barely can tell the difference between an 8bit monitor and a
10 bit monitor, there is no need for a 14 bit or 16 bit monitor. The key is
taking high bit data and showing it in the normal spectrum.

--
Sandman