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A future technology for dSLRs?

 
 
nospam
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      11-22-2009
In article <(E-Mail Removed)>, Alfred
Molon <(E-Mail Removed)> wrote:

> A full colour sensor, an idea some people here hate so much.


it's not that people hate it, it's that there's a lot of drawbacks that
some people blindly dismiss. a full colour sensor would be better *if*
it didn't compromise on high iso, dynamic range, frame rate and colour
accuracy. it also triples the storage and processing requirements.
foveon loses on all of them. nothing is perfect, and bayer is an
excellent tradeoff of what is currently possible.

> So why is
> Hasselblad implementing it, if there is no need for full colour
> information at each pixel?


they're moving the sensor and combining the results. that's not the
same as a full colour sensor and it certainly won't work very well for
anything with motion in it. it's also not cheap.
 
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Wolfgang Weisselberg
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      11-22-2009
Alfred Molon <(E-Mail Removed)> wrote:
> A full colour sensor, an idea some people here hate so much. So why is
> Hasselblad implementing it, if there is no need for full colour
> information at each pixel?


Well, colour still photography and colour film by shooting through
3 different filters is actually a very very old technology.
It never worked well with moving subjects, why should it work
better for Hasselblad? Do they change the laws of physics?

As for why H is doing it ... because people like you decide that
photographers have to have full colour sensors or you won't use,
buy, etc. their shots. So everyone must buy H.

-Wolfgang
 
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Outing Trolls is FUN!
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      11-22-2009
On Sat, 21 Nov 2009 17:03:58 -0500, nospam <(E-Mail Removed)> wrote:

>In article <he9nis$9ki$(E-Mail Removed)-september.org>, Charles
><(E-Mail Removed)> wrote:
>
>> >> I'm still rooting for Foveon II, as it seems more realistic to me as a
>> >> way
>> >> to leave (progress beyond) Bayer demosaicing.
>> >
>> > don't hold your breath on that one, and bayer actually works quite well.

>>
>> Agreed as to both points. However, the Foveon technology intrigues me with
>> its elegance ... just like nuclear fusion. Probably both great ideas that
>> will never actually pan out at any practical level.

>
>foveon is anything but elegant. it doesn't actually sense pure red,
>green and blue like in the ads. there's a lot of overlap in the three
>layers,


About as much overlap in the filters on a Bayer sensor.

Go educate yourself, troll.

 
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David J Taylor
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      11-22-2009
"Alfred Molon" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) ...
[]
> It's for static scenes of course, but it is effectively a full colour
> sensor, regardless of how they collect the full colour information. The
> only thing they have to add is the piezo actuators, so the additional
> cost will be small.
> --
>
> Alfred Molon


... and probably something which could be easily added to any sensor-shift
camera at little cost, perhaps providing /some/ image quality improvement.
It should have better colour accuracy than the Foveon implementation.
Whether there are many lenses that would justify the potential quadrupling
of the resolution is another question. To get that resolution means that
you would want a less severe anti-alias filter, or even omit the AA
filter, which could then mean that the camera was more likely to see Moiré
artefacts when not using multi-shot mode.

Cheers,
David

 
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Better Info
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Posts: n/a
 
      11-22-2009
On Sun, 22 Nov 2009 09:44:02 GMT, "David J Taylor"
<(E-Mail Removed)-this-bit.nor-this-part.co.uk.invalid> wrote:

>"Alfred Molon" <(E-Mail Removed)> wrote in message
>news:(E-Mail Removed) m...
>[]
>> It's for static scenes of course, but it is effectively a full colour
>> sensor, regardless of how they collect the full colour information. The
>> only thing they have to add is the piezo actuators, so the additional
>> cost will be small.
>> --
>>
>> Alfred Molon

>
>.. and probably something which could be easily added to any sensor-shift
>camera at little cost, perhaps providing /some/ image quality improvement.
>It should have better colour accuracy than the Foveon implementation.
>Whether there are many lenses that would justify the potential quadrupling
>of the resolution is another question. To get that resolution means that
>you would want a less severe anti-alias filter, or even omit the AA
>filter, which could then mean that the camera was more likely to see Moiré
>artefacts when not using multi-shot mode.
>
>Cheers,
>David


If the sensor is shifted in sub-pixel increments, then much higher
resolutions are available for both chroma and luma.

http://www.photoacute.com/mtf.html

 
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David J Taylor
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      11-22-2009

"Alfred Molon" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) ...
> In article <CJ7Om.7526$(E-Mail Removed)>, David J
> Taylor says...
>> Whether there are many lenses that would justify the potential
>> quadrupling
>> of the resolution is another question.

>
> Hasselblad are not quadrupling the resolution, they are just achieving
> the full nominal resulution of the sensor (as opposed to Bayer sensors,
> where the effective resulution is somewhere between ~ 30-100% of the
> pixel count, depending on the scene captured).
> In other words with their 39MP sensor, with this shift technology they
> obtain an image with 39MP of information, while with a Bayer sensor you
> are somewhere between 10 and 39MP of information. The numbers are of
> course just guesstimates.
> --
>
> Alfred Molon


So 10 => 39 isn't potential quadrupling? Even as a guesstimate? <G>

My question about lenses stands - how many are actually good enough the
reach the full resolution (rather than the lower "Bayer resolution") of
today's high-end DSLRs, even with ideal taking conditions?

Cheers,
David

 
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nospam
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      11-22-2009
In article <(E-Mail Removed)>, Outing Trolls
is FUN! <(E-Mail Removed)> wrote:

> >foveon is anything but elegant. it doesn't actually sense pure red,
> >green and blue like in the ads. there's a lot of overlap in the three
> >layers,

>
> About as much overlap in the filters on a Bayer sensor.


significantly more. see the foveon patents.
 
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nospam
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      11-22-2009
In article <(E-Mail Removed)>, Alfred
Molon <(E-Mail Removed)> wrote:

> > i assume by zoom you mean pixel peep, and if you do that you can see
> > all sorts of problems. why not look at photos normally? did you grain
> > peep film too?

>
> No. Make an enlargement and you will see how much resolution a photo
> really has. And if you can't make enlargements, what is the point of
> having a high pixel count?


since bayer cameras have as much as 5 times as many pixels (in the same
35mm form factor), you can make substantially bigger enlargements than
with foveon. if you step up to medium format backs, it's over 12 times
as many pixels.

do you regularly make 20" x 30" posters?
 
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nospam
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      11-22-2009
In article <(E-Mail Removed)>, Alfred
Molon <(E-Mail Removed)> wrote:

> In article <211120091910312644%(E-Mail Removed)>, nospam says...
> > In article <(E-Mail Removed)>, Alfred
> > Molon wrote:
> >
> > > A full colour sensor, an idea some people here hate so much.

> >
> > it's not that people hate it, it's that there's a lot of drawbacks that
> > some people blindly dismiss. a full colour sensor would be better *if*
> > it didn't compromise on high iso, dynamic range, frame rate and colour
> > accuracy. it also triples the storage and processing requirements.
> > foveon loses on all of them. nothing is perfect, and bayer is an
> > excellent tradeoff of what is currently possible.

>
> We are not discussing the implementation, only if it would be preferable
> to have full colour sensor.


of course it would be preferable *if* you could do it without
compromising anything else. unfortunately, there's no free lunch.

the reality is you end up compromising on things which are far more
important than having higher colour resolution. you *will* see higher
noise and colour casts, but you won't see the added colour resolution
and a slow frame rate is not desirable for some types of photography,
such as sports.
 
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nospam
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      11-22-2009
In article <(E-Mail Removed)>, Alfred
Molon <(E-Mail Removed)> wrote:

> Hasselblad are not quadrupling the resolution, they are just achieving
> the full nominal resulution of the sensor (as opposed to Bayer sensors,
> where the effective resulution is somewhere between ~ 30-100% of the
> pixel count, depending on the scene captured).


completely wrong.

> In other words with their 39MP sensor, with this shift technology they
> obtain an image with 39MP of information, while with a Bayer sensor you
> are somewhere between 10 and 39MP of information. The numbers are of
> course just guesstimates.


yes, wild guesstimates that are completely bogus.
 
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