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07-02-2010, 08:41 AM   #16
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QuoteOriginally posted by luck1 Quote
Foveons chip per pixel sharpnes is so huge, it is limited by the lens + the color output is superb, thanks to its technology. The only problem is its high ISO performance
Actually, color output is Foveon's achilles' heel. With a Bayer-style sensor, the color filters over each photosite can be specified with pretty much whatever precision is desired. With Foveon, the distinction between the different colors is due to the different light-absorbing properties of silicon, and while clever, it turns out to be less than ideal.

Specifically, each color sensor picks up a wider spectrum than ideal, and not exactly tuned to the pure red, green, and blue used in normal RGB colorspace. Straightening all of this out means loss of signal, so you get noisier high ISO. Worse, though, you get strange color shifts.

One site with examples (from the DP1):
Ian Bogost - Technical Evolution and Creative Constraint

Advances in Foveon technology might help to some degree, and of course going full frame would give another stop of light gathering without increasing ISO, but since the problem is basically intrinsic to the design, I wouldn't bet my camera company's future on it. (Sorry, Sigma -- at least you've got the third-party lens market.)

I'm all for more interesting sensor designs, though. I think the Bayer-like patterns which include "clear" photosites are definitely interesting, and we may -- especially as wide-gamut displays become more common -- see a return of arrays which include more different colors. (Like Sony's red-green-blue-emerald.)


Last edited by mattdm; 07-02-2010 at 12:08 PM.
07-02-2010, 08:56 AM   #17
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I'd be more intrested to know why Sigma's new camera didn't include body based image stablization -- which would have made their whole system and compliment of lenses a lot more attractive.
07-02-2010, 09:26 AM   #18
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QuoteOriginally posted by nanok Quote
one must understand the bayer sensor resolution is (partly) a lie, as it is interpolated, foveon claims of 14mp at 2640x1760 pixels is based on the fact that you can interpolate to upscale the image, and get the same image, as sharp as a 14mp bayer sensor (which is reasonable, as most people these days think in terms of bayer-resolution, so foveon must relate to that, to be able to market their product).
Or simply as I would say it: "Foveon is telling a lie" :-)
07-02-2010, 10:13 AM   #19
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QuoteOriginally posted by techmulla Quote
Any tech gurus out there, comments will be welcomed
It's simply not true that Foveon is better than the rest of the image processing sensor technology. Nor quantum film. Nor black silicon.

I could go into details but won't do it for this topic. Trichroic beamsplitting microlenses would be better than the rest of the image processing sensor technology.

07-02-2010, 02:45 PM   #20
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You know what would be really great? I have an idea for a sensor that doesn't even use electricity -- so there's no readout noise whatsoever. Pixel density is basically unlimited. It uses special light-sensitive chemicals to capture images on a very thin, inexpensive plastic substrate. And best of all, if you want to increase sensitivity, all you do is switch to a different "cartridge" -- there's no need to get a new camera every year! It's the future, I tell you!
07-02-2010, 04:25 PM   #21
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QuoteOriginally posted by Quicksand Quote
You know what would be really great? I have an idea for a sensor that doesn't even use electricity -- so there's no readout noise whatsoever. Pixel density is basically unlimited. It uses special light-sensitive chemicals to capture images on a very thin, inexpensive plastic substrate. And best of all, if you want to increase sensitivity, all you do is switch to a different "cartridge" -- there's no need to get a new camera every year! It's the future, I tell you!
i dont know.... sounds awful life magic to me!!!
07-02-2010, 04:32 PM   #22
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QuoteOriginally posted by Quicksand Quote
You know what would be really great? I have an idea for a sensor that doesn't even use electricity -- so there's no readout noise whatsoever. Pixel density is basically unlimited. It uses special light-sensitive chemicals to capture images on a very thin, inexpensive plastic substrate. And best of all, if you want to increase sensitivity, all you do is switch to a different "cartridge" -- there's no need to get a new camera every year! It's the future, I tell you!
Shhhh!!! I have trying to get that special system patented before the big boys figure it out.
07-02-2010, 10:30 PM   #23
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It would also be much more expensive and primarily only attractive to those that like HDR photographs.

QuoteOriginally posted by mithrandir Quote
What I would like to see is three simultaneous processors using a CCD sensor. One would process at -2EV, one at 0EV, and one at +2EV. All three versions would be saved to be combined in HDR software. This would remove the motion problems currently experienced in HDR and would dramatically widen the dynamic range of the sensor.


07-03-2010, 06:55 AM   #24
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QuoteOriginally posted by mithrandir Quote
What I would like to see is three simultaneous processors using a CCD sensor. One would process at -2EV, one at 0EV, and one at +2EV. All three versions would be saved to be combined in HDR software. This would remove the motion problems currently experienced in HDR and would dramatically widen the dynamic range of the sensor.
Tsssss...
There is Fuji Super CCD

Btw, why foveon sucks?
1) low resolution. It's 4.7 Mp only. So if we upscale - we get no advantage of sharpness
2) noise (and I assume noise at long expositions too)
3) color performance (bad tones for high iso and deep red Ferrari becoming purple car)

Last edited by Zebooka; 07-03-2010 at 07:02 AM.
07-03-2010, 08:08 PM   #25
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QuoteOriginally posted by konraDarnok Quote
I'd be more intrested to know why Sigma's new camera didn't include body based image stablization -- which would have made their whole system and compliment of lenses a lot more attractive.
because Sigma sells one lens design to Canon, Nikon, Sony, Pentax, Sigma and sometimes 4/3 mounts... so they have to make lens based stabilization (= Canon & Nikon)... plus they don't have enough volume in camera sales, so they try to be as cheap as possible w/ anything that goes into the camera
07-06-2010, 06:58 AM   #26
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QuoteOriginally posted by techmulla Quote
Why don't pentax use this technology in its upcoming model. it is supposedly better than the rest of the image processing sensor technology.

Any tech gurus out there, comments will be welcomed
Supposedly it is, and when it first came out, lots of claims were made that it would revolutionize digital photography.

It didn't... It pretty much fizzled and became a Sigma niche, and didn't really deliver much better results than its contemporaries. Bayer sensors have since come much farther than Foveon sensors have.

It's why I'm always skeptical whenever someone promises a revolution in sensor technology - it almost always proves to be vaporware, fails to deliver, or blows away the state of Bayer technology when it's announced but not by the time it hits the consumer market.
07-08-2010, 09:12 PM   #27
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I recently bought a DP2s to use as a carry all compact. The Foveon technology definitely has something going for it. I think the images have a 3D look bayer sensors just don't capture. It is not perfect but there is a sharpness and texture detail especially material like clothing that Foveon resolves much better than bayer sensors. It is less plastic looking.

I have only had limited use with the DP2s so far. The camera itself could be better designed. It doesn't feel cheap but it doesn't have a certain polish like a Panasonic LX3 has. The lens is very good though.

Working with the files hasn't been easy. The Software Sigma supplies is not bad and gives the best results. There is just an odd thing were the files when brought into the software have great natural looking color but the software does something to the file that automatically changes the color. I have not been able to figure out how to turn this off or get the color back to that point they look great for the brief moment before they get changed. It is really odd. I don't think Foveon can't do color well I think it is just that the software cripples your ability to adjust it properly. Using Adobe ACR is even worse.

Here are some comparison examples:

K-7 SMC A-28mm f2 at f8 1/200 sec ISO 100



DP2s f8 1/200 sec ISO 50



K-7 SMC A-28mm f2 at f8 1/200 sec ISO 100



DP2s f8 1/320 sec ISO 50



I tried to keep all the parameters as close as possible. In no way was this scientific but more real world. I used similar focal lengths. The DP2s is around 40mm 35 equivalent so I used the 28mm on the K-7.

What is holding back Foveon is lack of R&D funding.
07-08-2010, 09:57 PM   #28
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I would like to see a monochrome K-7. No Bayer filter. The resolution of a true 14MP monochrome sensor would be amazing. I still shoot B&W in my Contax 645 and B&W is still my favorite medium. In the modern world of over-saturated colors there is probably not much of a market for such a camera, but I would buy one.
07-08-2010, 10:47 PM   #29
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QuoteOriginally posted by mithrandir Quote
What I would like to see is three simultaneous processors using a CCD sensor. One would process at -2EV, one at 0EV, and one at +2EV. All three versions would be saved to be combined in HDR software. This would remove the motion problems currently experienced in HDR and would dramatically widen the dynamic range of the sensor.
There's only so much you can do by manipulating electronic gain. Well capacity and noise floor remain the same, so there would be little advantage over just exposing to fit the histogram best within the range of our latest high-performance sensors. You'd make better gains by simply designing sensors with greater well capacity and less electronic noise (basically what they do with every new generation of sensor).

To truly expand the DR that can be captured in an image, you need to change the amount of light hitting the sensor, not how dark or bright the sensor's processors interpret that light as being. Theoretical sensors that can alter exposure time on a per-pixel basis or a mode where two or three images of different duration are taken with a single flip of the shutter are some practical ways this could happen (the theoretical sensor is a way off but is a logical evolution of the upcoming global-shutter sensors). Fuji's Super CCD is also a practical means of extending DR but they don't seem to have made any real developments of the technology since the S3 Pro came out, just refinements in the S5 and then nothing.
07-09-2010, 02:28 AM   #30
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QuoteOriginally posted by Rico Quote
Here are some comparison examples:
I manually whitebalanced both images to the white tent on the left hand side and shifted colors in the K-7 sample to get X3's wrong blue sky effect (I exxagerated a little bit. In lightroom, you mostly draw the Aqua, Blue and Magenta channel sliders to -20 or -40 and push the Blue channel towards a Green hue).

The result is attached. Except for wrong colors, I cannot see a difference. However, I wonder which X3 color calibration gives such wrong colors...

Last edited by falconeye; 06-15-2011 at 05:29 AM.
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