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Author Topic: Camera industry in the dumpster - article  (Read 33376 times)

Ray

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Re: Camera industry in the dumpster - article
« Reply #220 on: April 01, 2014, 04:13:19 AM »

Better than ideal? :-) 

Okay! For the benefit of those who demand complete literalism and precise language all of the time, I'm prepared to rephrase that statement as follows:

"A large 4K TV screen seems to be an ideal way to display one's photos with currently available technology, although, when, and if, 8K becomes an option and becomes readily available, then that will be even better, setting a new ideal."

Any criticism?  ;D


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A Bayer sensor of 10 MP has only 2.5 million red or blue sites. A 4k tv has roughly 8 million (full-color) pixels. Thus, you would "need" a 40 MP camera in order to feed all subpixels of a 4k tv with potentially independent information. You might have to multiply this number even further to account for OLPF filtering, overlapping color filters, etc.

The Bayer system of complementing each pixel of a specific primary color, with additional, interpolated pixels comprising the other two primaries, is a necessary process in order for us to see a color image, whether the image be an in-camera jpeg or a RAW file converted in post processing. One could describe such a process as 'up sampling' or interpolation. Whatever the terminology, an 8mp camera, such as the Canon 20D, produces an image with 8 million pixels, each consisting of the 3 values of R,G,B, resulting in a 24MB file, in 8 bit color.

That's the image we start off from. If the image is 8mp with a 3:2 aspect ratio, then a small amount of downsampling will be required to fit it onto a 4K screen. If the image is cropped to a 16:9 aspect ratio, then a small amount of upsampling will be required to fill a 4k screen. Hope that is clear to the literally-minded.  ;D

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Displays are often limited by the ambient light in the room. If you are in a bright day-lit room, display blacks won't be any blacker than charcoal, I guess. The whites won't be any whiter than the maximum display output (or the setting that feels comfortable to you). The gazillion to one measurements can probably only be achieved in a dark home cinema with black paint on the walls.

Of course! Whatever the quality of the display, whether it be a TV screen or a print, the lighting conditions in the viewing environment have to be appropriate in order for one to fully appreciate the detail, contrast and color. If there's no light at all, you see nothing on a print. If you have a bright beam of sunlight shining through your window onto your TV screen, then that's going to seriously upset the quality of the image you see. That's understood.

However, these new OLED screen from LG appear to have 4 pixels, one of which is white. The screens not only have the potential to be brighter than a conventional LCD screen, but each individual pixel can be gradually dimmed till it's completely switched off. All the reviews I've read of the few standard-HD OLED TV models that are available, claim that the picture quality is stunning, just 'out of this world'. (Not literally, of course).  ;D

The 4k models should be even more stunning, but not so stunning that one is just 'floored' and unable to appreciate the picture, I hope.  ;D
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hjulenissen

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Re: Camera industry in the dumpster - article
« Reply #221 on: April 01, 2014, 06:17:01 AM »

The Bayer system of complementing each pixel of a specific primary color, with additional, interpolated pixels comprising the other two primaries, is a necessary process in order for us to see a color image, whether the image be an in-camera jpeg or a RAW file converted in post processing. One could describe such a process as 'up sampling' or interpolation. Whatever the terminology, an 8mp camera, such as the Canon 20D, produces an image with 8 million pixels, each consisting of the 3 values of R,G,B, resulting in a 24MB file, in 8 bit color.
The Bayer system is not a "necessary process" in that other, competing technologies does this differently (with other drawbacks).

If you have a (uncommon) scene that in practice only excite the red sensels, then a Bayer camera featuring 10 million sensels will have 2.5 million scene-recording sensels. If you display this on a display featuring 8 million full-color pixels, then you are obviously not exploiting the displays spatial resolution capabilities. That was my only point, and I am sure that you are aware of this.

Now, there are many practical reasons why people should not worry about this.

-h
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Ray

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Re: Camera industry in the dumpster - article
« Reply #222 on: April 01, 2014, 10:24:33 AM »

The Bayer system is not a "necessary process" in that other, competing technologies does this differently (with other drawbacks).

If you have a (uncommon) scene that in practice only excite the red sensels, then a Bayer camera featuring 10 million sensels will have 2.5 million scene-recording sensels. If you display this on a display featuring 8 million full-color pixels, then you are obviously not exploiting the displays spatial resolution capabilities. That was my only point, and I am sure that you are aware of this.


Indeed I am. Your point is about the image quality differences between the Foveon and Bayer systems per megabyte of image data. I accept that a 15mp Sigma DP Merrill can produce more detailed images than a 15mp Canon 50D. However, to fit those images from both cameras on a 4k screen they would both have to be downsampled or cropped. That is, a certain amount of image data would have to be discarded in both cases, regardless of the initial starting quality.

On the other hand, a full image from the 4.7mp SD15, sometimes described as a 14mp camera, would have to be interpolated to fit the height of a 4k screen. The resolution of the 4k screen is unnecessarily high for that camera and earlier Foveon models.


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barryfitzgerald

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Re: Camera industry in the dumpster - article
« Reply #223 on: April 09, 2014, 06:44:54 PM »

I can only speak from my own experiments, but the sigma images do well in enlargement as 4k is only around 8mp I would be surprised if they didn't look good at that
Even a 6mp bayer would look fine
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