Sony A100 to A700

[A complimentary Cc of this posting was sent to
frederick
<lost.TakeThisOut@sea.com>], who wrote in article <1212458499.612758@ftpsrv1>:
> > Yes, this "70%" figure is mostly related to the sensor being of Bayer
> > type. (See the comparison of Sigma vs Canikon in one of the latest
> > reviews on dpreview: it turns out that there is a significant "portion
> > of truth" in Sigma's "Foveon pixel count".)

> Not as significant as the fact that there's something fundamentally
> wrong with the science behind the idea that you should devise a special
> way of testing to show an "advantage" not seen using methods accepted
> for many years.

I suspect you may have very little clue in this topic. Read the
dpreview analysis (turns out that THIS topic is well within THEIR
level of technical expertise; I did not find any obvious goofs in what
they write). The conclusion is quite surprising...

[Keep in mind that they did not do any analysis of precision of
color reproduction; HERE Foveon should be, according to X3
documentation, quite bad.]

Hope this helps,
Ilya
 >> Stay informed about: Sony A100 to A700 

[A complimentary Cc of this posting was sent to
nospam
<nospam.DeleteThis@nospam.invalid>], who wrote in article <020620082332275294%nospam@nospam.invalid>:
> there is no truth in the 'foveon pixel count.' pixels are pixels,
> regardless what sigma/foveon claim (and they even use the term
> inconsistently, further proof that their method is bogus).
>
> the reason for the difference is that sigma omits the anti-alias filter
> and thereby the sensor can resolve closer to nyquist, along with a lot
> of aliasing and heavy sharpening, which some people mistake for real
> resolution. it also does better on colour resolution charts but that
> isn't anything that matters to human vision. it just makes bayer look
> worse in an edge case that never occurs in nature.

You can count angels at the point of a needle as long as you want.
The fact remains the fact.

DPreview (which is often suspected for prejudice in Canikon direction)
compares shots from a 5MP x 3 sensor, and from Bayer sensors with
(several) larger MP count. The conclusion was quite surprising (for me).

Hope this helps,
Ilya
 >> Stay informed about: Sony A100 to A700 

In article <g22qnf$2l2j$1@agate.berkeley.edu>, Ilya Zakharevich
<nospam-abuse.RemoveThis@ilyaz.org> wrote:

> You can count angels at the point of a needle as long as you want.
> The fact remains the fact.

what fact is that? a pixel is a spatial element of an image, and not a
layer within. the sd14/dp1 sensor has 4.7 megapixels. period.

> DPreview (which is often suspected for prejudice in Canikon direction)
> compares shots from a 5MP x 3 sensor, and from Bayer sensors with
> (several) larger MP count. The conclusion was quite surprising (for me).

nothing surprising about an edge case designed to exploit a weakness in
bayer, and one which doesn't matter to humans. there are edge cases
where foveon falls apart too, and even more so than bayer does.
 >> Stay informed about: Sony A100 to A700 

Alfred Molon wrote:
> In article <g21iko$28mi$1@agate.berkeley.edu>, Ilya Zakharevich says...
>
>> In other words, this kit lens can overload the sensor in many settings.
>
> I'm not sure 70% of the sensor line count is sufficient. But I'm not
> deep enough in the math to be able to discuss this further.
> In any case, if the sensor were full colour, you'd want to have an ideal
> lens with 100% MTF until the line count of the sensor (and an ideal AA
> filter with a rectangle response until Nyquist).
> With a Bayer sensor you do the colour interpolation, and the situation
> is different.
>
> By the way, these are MTF50 numbers and having a higher MTF (ideally
> 100%) would be preferable.
>
> Besides most if not all reviews of the Sony Alpha 350 (14MP, approx.
> 3000 lines) point out that the Sony 18-70 lens is a limiting factor and
> state that a better lens is desperately needed.

That 18-70 Sony lens apparently isn't a good performer. IIRC DPReview
didn't think much of it either on 10+ mp dslrs (a700?)
I don't know what the alternatives for Sony are like, but some aps-c
format consumer zooms for other brands are easily "up to the
requirements" of >12mp aps-c sensors. The camera makers will keep
making new higher pixel count aps-c dslrs, and probably newer sharper
lenses to match for some time yet. I don't know what the Nikkor 16-85
will be like, but they need to justify the high price somehow <g>. At
10-15mp, these dslrs are still equivalent pixel density to only about
2-3mp compact cameras, and for compact cameras, increased megapixels
only became mainly pointless (IMO) once they hit over about 5-6 megapixels.
 >> Stay informed about: Sony A100 to A700 

In article <020620082332275294%nospam@nospam.invalid>, nospam says...

> there is no truth in the 'foveon pixel count.' pixels are pixels,
> regardless what sigma/foveon claim (and they even use the term
> inconsistently, further proof that their method is bogus).
>
> the reason for the difference is that sigma omits the anti-alias filter
> and thereby the sensor can resolve closer to nyquist, along with a lot
> of aliasing and heavy sharpening, which some people mistake for real
> resolution. it also does better on colour resolution charts but that
> isn't anything that matters to human vision. it just makes bayer look
> worse in an edge case that never occurs in nature.

This has been discussed to death and there is no point to reopen the
discussion. Do a Google search on the archives to find out why with
Bayer sensors the effective resolution is lower than the nominal pixel
count.
--

Alfred Molon
------------------------------
Olympus 50X0, 8080, E3X0, E4X0, E5X0 and E3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site
 >> Stay informed about: Sony A100 to A700 

In article <MPG.22af384c825cb82298bc8d DeleteThis @news.supernews.com>, Alfred
Molon <alfred_molon DeleteThis @yahoo.com> wrote:

> In article <020620082332275294%nospam@nospam.invalid>, nospam says...
>
> > there is no truth in the 'foveon pixel count.' pixels are pixels,
> > regardless what sigma/foveon claim (and they even use the term
> > inconsistently, further proof that their method is bogus).
> >
> > the reason for the difference is that sigma omits the anti-alias filter
> > and thereby the sensor can resolve closer to nyquist, along with a lot
> > of aliasing and heavy sharpening, which some people mistake for real
> > resolution. it also does better on colour resolution charts but that
> > isn't anything that matters to human vision. it just makes bayer look
> > worse in an edge case that never occurs in nature.
>
> This has been discussed to death and there is no point to reopen the
> discussion.

yes, it has been hashed to death on numerous forums, however, the myths
continue.

> Do a Google search on the archives to find out why with
> Bayer sensors the effective resolution is lower than the nominal pixel
> count.

it's the lack of an anti-alias filter in the sigma cameras along with
sharpening in the raw processing (which bayer cameras generally are set
to much less), and not anything inherent to foveon.
 >> Stay informed about: Sony A100 to A700 

Ilya Zakharevich wrote:
> [A complimentary Cc of this posting was sent to
> frederick
> <lost RemoveThis @sea.com>], who wrote in article <1212458499.612758@ftpsrv1>:
>>> Yes, this "70%" figure is mostly related to the sensor being of Bayer
>>> type. (See the comparison of Sigma vs Canikon in one of the latest
>>> reviews on dpreview: it turns out that there is a significant "portion
>>> of truth" in Sigma's "Foveon pixel count".)
>
>> Not as significant as the fact that there's something fundamentally
>> wrong with the science behind the idea that you should devise a special
>> way of testing to show an "advantage" not seen using methods accepted
>> for many years.
>
> I suspect you may have very little clue in this topic. Read the
> dpreview analysis (turns out that THIS topic is well within THEIR
> level of technical expertise; I did not find any obvious goofs in what
> they write). The conclusion is quite surprising...
>
> [Keep in mind that they did not do any analysis of precision of
> color reproduction; HERE Foveon should be, according to X3
> documentation, quite bad.]
>
> Hope this helps,

It doesn't help. The defense for the DP review "analysis" is the words
"per pixel" resolution, and their noting of the fact that bayer sensors
of higher pixel count have (unsurprisingly except to Foveon zealots)
higher resolution.

Their conclusion also lists more "cons" than I've seen for any camera
for quite a while - as well as a low overall rating.

And I stand behind my comments above - it's dishonest / unscientific to
put the colour-resolution chart test in place of the normal chart tests.
If you wanted to show "optimum" performance in those charts, then
DPreview don't do it with other cameras (usually default jpeg output and
using old design lenses - not raw converted and optimised with OEM
converters and using the best possible lenses), so making an exception
for the unusual and generally not very good Sigma foveon cameras is only
helping to perpetuate myths.

Hope this helps.
 >> Stay informed about: Sony A100 to A700 

[A complimentary Cc of this posting was sent to
frederick
<lost.TakeThisOut@sea.com>], who wrote in article <1212478815.530753@ftpsrv1>:
> It doesn't help. The defense for the DP review "analysis" is the words
> "per pixel" resolution, and their noting of the fact that bayer sensors
> of higher pixel count have (unsurprisingly except to Foveon zealots)
> higher resolution.

Wrong.

> If you wanted to show "optimum" performance in those charts, then
> DPreview don't do it with other cameras (usually default jpeg output and
> using old design lenses - not raw converted and optimised with OEM
> converters and using the best possible lenses), so making an exception
> for the unusual and generally not very good Sigma foveon cameras is only
> helping to perpetuate myths.

Now we know that it is not a myph. Visual comparison of Foveon images
and Bayer images gives an advantage of about 2x in pixel count.
(Myself, I was expecting something about 1.5x...)

Hope this helps,
Ilya
 >> Stay informed about: Sony A100 to A700 

In article <1212478815.530753@ftpsrv1>, frederick says...

> And I stand behind my comments above - it's dishonest / unscientific to
> put the colour-resolution chart test in place of the normal chart tests.

Since the world is not black and white, it makes sense to use colour
resolution test targets instead of black and white ones.
--

Alfred Molon
------------------------------
Olympus 50X0, 8080, E3X0, E4X0, E5X0 and E3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site
 >> Stay informed about: Sony A100 to A700 

In article <MPG.22af39e255bfa7d598bc8e.RemoveThis@news.supernews.com>, Alfred
Molon <alfred_molon.RemoveThis@yahoo.com> wrote:

> In article <1212478815.530753@ftpsrv1>, frederick says...
>
> > And I stand behind my comments above - it's dishonest / unscientific to
> > put the colour-resolution chart test in place of the normal chart tests.
>
> Since the world is not black and white, it makes sense to use colour
> resolution test targets instead of black and white ones.

the world is indeed colour, but it's not saturated stripes with
constant luminance. bayer sensors are designed to work the way human
eyes do, and that's maximize luminance resolution. foveon is nice in
theory, but it has a lot of shortcomings, such as metamerism, noise,
very critical white balance and significantly more data to move.

put a colour luminance chart on the wall next to a b/w chart and see
how well *you* can resolve it (assuming you don't get a headache first
from the colour chart). you'll find that you won't see anywhere near
as much detail on the colour chart as the b/w chart. why bother
capturing what you can't see?
 >> Stay informed about: Sony A100 to A700 

Ilya Zakharevich wrote:
> [A complimentary Cc of this posting was sent to
> frederick
> <lost.TakeThisOut@sea.com>], who wrote in article <1212478815.530753@ftpsrv1>:
>> It doesn't help. The defense for the DP review "analysis" is the words
>> "per pixel" resolution, and their noting of the fact that bayer sensors
>> of higher pixel count have (unsurprisingly except to Foveon zealots)
>> higher resolution.
>
> Wrong.
>
>> If you wanted to show "optimum" performance in those charts, then
>> DPreview don't do it with other cameras (usually default jpeg output and
>> using old design lenses - not raw converted and optimised with OEM
>> converters and using the best possible lenses), so making an exception
>> for the unusual and generally not very good Sigma foveon cameras is only
>> helping to perpetuate myths.
>
> Now we know that it is not a myph. Visual comparison of Foveon images
> and Bayer images gives an advantage of about 2x in pixel count.
> (Myself, I was expecting something about 1.5x...)
>
> Hope this helps,
> Ilya
I don't know what you are arguing about.
4.69 x 2 = <10mp
IIRC DPreview already said the ("3.4mp x 3") SD10 was similar to 6mp
dslrs in resolution - so nothing new here.

"So what we'd really like to see is a sensor that combines the Foveon's
per pixel resolution with the output size of a modern DSLR. It would no
doubt take image quality onto another level and beat current Bayer
sensors by a mile."

Yes - sure - but not with noise etc.. By the time Foveon come up with
this (a "10mp x 3" sensor), do you expect that Bayer sensors will still
be where they are today? (or were yesterday - Sony, Canon, Nikon, Pentax
are already beyond 10mp).
 >> Stay informed about: Sony A100 to A700 

This message is not archived
 >> Stay informed about: Sony A100 to A700 

Hey, a lot of good info'
But still undecided

Ta
Ron


"Ron and Gail Smith" <ron_smith.RemoveThis@clear.net.nz> wrote in message
news:483dcdbb@clear.net.nz...
> Hi All
> Thinking of upgrading from Sony A100 to Sony A700 and wondering if anyone
> has done
> that and what your thoughts are?
> I'd been interested to know
>
> Regards
> Ron
>
 >> Stay informed about: Sony A100 to A700