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Sigma cameras try to appeal to real shooters



 
 
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  #11  
Old April 16th 17, 06:14 AM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default Sigma cameras try to appeal to real shooters

In article ,
nospam wrote:

In article , Alfred
Molon wrote:

That would put the real resolution between 6.5 and 25.4MP.


Well no, it's not that simple.


it's not simple but it's correct.

the actual resolution of that sigma camera varies depending on the
colour of the subject, something which is *never* desirable.


Unless you are going for monochrome. Put on a blue filter and a 25MP
monochrome you've got. Think Gershwin and "Rhapsody in blue"...

because the bottom two layers are 6 mp, it can only resolve slightly
better than an ordinary 6 mp camera, unless the subject is mostly blue,
in which case it will be a bit better because the top layer, which
responds to blue, has higher pixel count and can resolve more detail.

real world subjects are *not* mostly blue nor are they a spectral match
for the top layer.

in other words, it's a 6 mp camera that in some cases can do a little
better, with a whole ****load of artifacts because it's guessing most
of the details.

The real resolution of a Bayer sensor is probably around 50%-70% of the
pixel count, depending on the scene.


nonsense. first of all, resolution is not measured by pixel count and
second of all, bayer is close to its theoretical maximum (nyquist).

This Foveon sensor, if it doesn't
have three complete colour layers as you claim,


that's not what was claimed.

will have a somewhat
higher real resolution - perhaps 70% to 90% of the pixel count.


only if you properly count the pixels, which sigma nor its followers do.


The photo sites in a Bayer matrix should be a tad fuzzy. I would correct
the MP count through a dividing by the square root of two. I don't have
the math in order for that but it feels about right. A stack like the
Foveon have the pixel rate that the least dense layer has. In this case
6MP.

Another complication regarding the resolution of color: If you take a
look at the Foveon stack you must understand that the colors ain't 100
percent pure since every color but blue is filtered by the above layers.
I doubt that those filters are very clean...

You posted this link once. Thanks for that:

http://static.rcgroups.net/forums/at...51638-191-Stac
ked%20imager%20color%20response%20curves.jpg?d=114 9316976

The main wiki on the Foveon:

https://en.wikipedia.org/wiki/Foveon_X3_sensor
--
teleportation kills
  #12  
Old April 16th 17, 04:22 PM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Sigma cameras try to appeal to real shooters

In article , android
wrote:


That would put the real resolution between 6.5 and 25.4MP.

Well no, it's not that simple.


it's not simple but it's correct.

the actual resolution of that sigma camera varies depending on the
colour of the subject, something which is *never* desirable.


Unless you are going for monochrome. Put on a blue filter and a 25MP
monochrome you've got. Think Gershwin and "Rhapsody in blue"...


that's about the only use for that camera.

because the bottom two layers are 6 mp, it can only resolve slightly
better than an ordinary 6 mp camera, unless the subject is mostly blue,
in which case it will be a bit better because the top layer, which
responds to blue, has higher pixel count and can resolve more detail.

real world subjects are *not* mostly blue nor are they a spectral match
for the top layer.

in other words, it's a 6 mp camera that in some cases can do a little
better, with a whole ****load of artifacts because it's guessing most
of the details.

The real resolution of a Bayer sensor is probably around 50%-70% of the
pixel count, depending on the scene.


nonsense. first of all, resolution is not measured by pixel count and
second of all, bayer is close to its theoretical maximum (nyquist).

This Foveon sensor, if it doesn't
have three complete colour layers as you claim,


that's not what was claimed.

will have a somewhat
higher real resolution - perhaps 70% to 90% of the pixel count.


only if you properly count the pixels, which sigma nor its followers do.


The photo sites in a Bayer matrix should be a tad fuzzy.


they're not fuzzy.

I would correct
the MP count through a dividing by the square root of two.


what for?

I don't have
the math in order


clearly.

for that but it feels about right.


math isn't about what feels right.

A stack like the
Foveon have the pixel rate that the least dense layer has. In this case
6MP.


that part is true.

the sensor is limited by the two layers of 6 mp.

the 25 mp top layer is a slight improvement over a 6mp top layer, but
there's still roughly 2/3rds of the spectrum limited to 6 mp.

its biggest problem is that it has to upscale the bottom two layers to
25 mp, faking nearly everything in the process.

sigma claims a 51 mp equivalent which is pure fantasy.

Another complication regarding the resolution of color: If you take a
look at the Foveon stack you must understand that the colors ain't 100
percent pure since every color but blue is filtered by the above layers.
I doubt that those filters are very clean...


there's a ****load of overlap, which throws yet another wrench into
their claims.

You posted this link once. Thanks for that:

http://static.rcgroups.net/forums/at...51638-191-Stac
ked%20imager%20color%20response%20curves.jpg?d=114 9316976


that looks like it's from the patents.

The main wiki on the Foveon:

https://en.wikipedia.org/wiki/Foveon_X3_sensor


nothing more than a rehash of their false claims.
  #13  
Old April 16th 17, 05:43 PM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default Sigma cameras try to appeal to real shooters

In article ,
nospam wrote:

In article , android
wrote:


That would put the real resolution between 6.5 and 25.4MP.

Well no, it's not that simple.

it's not simple but it's correct.

the actual resolution of that sigma camera varies depending on the
colour of the subject, something which is *never* desirable.


Unless you are going for monochrome. Put on a blue filter and a 25MP
monochrome you've got. Think Gershwin and "Rhapsody in blue"...


that's about the only use for that camera.

because the bottom two layers are 6 mp, it can only resolve slightly
better than an ordinary 6 mp camera, unless the subject is mostly blue,
in which case it will be a bit better because the top layer, which
responds to blue, has higher pixel count and can resolve more detail.

real world subjects are *not* mostly blue nor are they a spectral match
for the top layer.

in other words, it's a 6 mp camera that in some cases can do a little
better, with a whole ****load of artifacts because it's guessing most
of the details.

The real resolution of a Bayer sensor is probably around 50%-70% of the
pixel count, depending on the scene.

nonsense. first of all, resolution is not measured by pixel count and
second of all, bayer is close to its theoretical maximum (nyquist).

This Foveon sensor, if it doesn't
have three complete colour layers as you claim,

that's not what was claimed.

will have a somewhat
higher real resolution - perhaps 70% to 90% of the pixel count.

only if you properly count the pixels, which sigma nor its followers do.


The photo sites in a Bayer matrix should be a tad fuzzy.


they're not fuzzy.


It's extrapolated data, dufuzz...

I would correct
the MP count through a dividing by the square root of two.


what for?


It's extrapolated data, dufuzz... And since the matrix is two by two the
correction factor should be between one and two...


I don't have
the math in order


clearly.


Yet the sky is blue...

for that but it feels about right.


math isn't about what feels right.

Sure is: Black numbers feels good, but red not so...
--
teleportation kills
  #14  
Old April 16th 17, 06:10 PM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Sigma cameras try to appeal to real shooters

In article , android
wrote:

will have a somewhat
higher real resolution - perhaps 70% to 90% of the pixel count.

only if you properly count the pixels, which sigma nor its followers do.

The photo sites in a Bayer matrix should be a tad fuzzy.


they're not fuzzy.


It's extrapolated data, dufuzz...


it's neither extrapolated nor is it fuzzy.

I would correct
the MP count through a dividing by the square root of two.


what for?


It's extrapolated data, dufuzz... And since the matrix is two by two the
correction factor should be between one and two...


it isn't.

the number of pixels is a physical property of the sensor. there is no
correction factor and it does not change. it is what it is.

I don't have
the math in order


clearly.


Yet the sky is blue...


actually, it's cyan.

for that but it feels about right.


math isn't about what feels right.

Sure is: Black numbers feels good, but red not so...


use blue ink.
  #15  
Old April 16th 17, 06:25 PM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default Sigma cameras try to appeal to real shooters

In article ,
nospam wrote:

In article , android
wrote:

will have a somewhat
higher real resolution - perhaps 70% to 90% of the pixel count.

only if you properly count the pixels, which sigma nor its followers
do.

The photo sites in a Bayer matrix should be a tad fuzzy.

they're not fuzzy.


It's extrapolated data, dufuzz...


it's neither extrapolated nor is it fuzzy.

I would correct
the MP count through a dividing by the square root of two.

what for?


It's extrapolated data, dufuzz... And since the matrix is two by two the
correction factor should be between one and two...


it isn't.


Sure is since the color measured by photo site is determined by of site
pixels.
--
teleportation kills
  #16  
Old April 16th 17, 06:34 PM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Sigma cameras try to appeal to real shooters

In article , android
wrote:

will have a somewhat
higher real resolution - perhaps 70% to 90% of the pixel count.

only if you properly count the pixels, which sigma nor its
followers
do.

The photo sites in a Bayer matrix should be a tad fuzzy.

they're not fuzzy.

It's extrapolated data, dufuzz...


it's neither extrapolated nor is it fuzzy.

I would correct
the MP count through a dividing by the square root of two.

what for?

It's extrapolated data, dufuzz... And since the matrix is two by two the
correction factor should be between one and two...


it isn't.


Sure is since the color measured by photo site is determined by of site
pixels.


chroma is determined by very complex calculations which have a
negligible effect on spatial resolution.

it also doesn't matter, since the human eye can't resolve chroma
particularly well (about 1/10th that of luma). bayer samples chroma at
half the rate it samples luma, which is about 5x more than people can
see.
  #17  
Old April 16th 17, 06:48 PM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default Sigma cameras try to appeal to real shooters

In article ,
nospam wrote:

In article , android
wrote:

will have a somewhat
higher real resolution - perhaps 70% to 90% of the pixel count.

only if you properly count the pixels, which sigma nor its
followers
do.

The photo sites in a Bayer matrix should be a tad fuzzy.

they're not fuzzy.

It's extrapolated data, dufuzz...

it's neither extrapolated nor is it fuzzy.

I would correct
the MP count through a dividing by the square root of two.

what for?

It's extrapolated data, dufuzz... And since the matrix is two by two
the
correction factor should be between one and two...

it isn't.


Sure is since the color measured by photo site is determined by of site
pixels.


chroma is determined by very complex calculations which have a
negligible effect on spatial resolution.

it also doesn't matter, since the human eye can't resolve chroma
particularly well (about 1/10th that of luma). bayer samples chroma at
half the rate it samples luma, which is about 5x more than people can
see.


Since you don't have a BW channel... Oki...
--
teleportation kills
  #18  
Old April 16th 17, 06:54 PM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default Sigma cameras try to appeal to real shooters

In article , android
wrote:


I would correct
the MP count through a dividing by the square root of two.

what for?

It's extrapolated data, dufuzz... And since the matrix is two by two
the
correction factor should be between one and two...

it isn't.

Sure is since the color measured by photo site is determined by of site
pixels.


chroma is determined by very complex calculations which have a
negligible effect on spatial resolution.

it also doesn't matter, since the human eye can't resolve chroma
particularly well (about 1/10th that of luma). bayer samples chroma at
half the rate it samples luma, which is about 5x more than people can
see.


Since you don't have a BW channel... Oki...


i didn't say bw. i said luma/chroma.
  #19  
Old April 16th 17, 07:04 PM posted to rec.photo.digital
android
external usenet poster
 
Posts: 3,854
Default Sigma cameras try to appeal to real shooters

In article ,
nospam wrote:

In article , android
wrote:


I would correct
the MP count through a dividing by the square root of two.

what for?

It's extrapolated data, dufuzz... And since the matrix is two by
two
the
correction factor should be between one and two...

it isn't.

Sure is since the color measured by photo site is determined by of site
pixels.

chroma is determined by very complex calculations which have a
negligible effect on spatial resolution.

it also doesn't matter, since the human eye can't resolve chroma
particularly well (about 1/10th that of luma). bayer samples chroma at
half the rate it samples luma, which is about 5x more than people can
see.


Since you don't have a BW channel... Oki...


i didn't say bw. i said luma/chroma.


Oki...
--
teleportation kills
 




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