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Faking and expensive tilt-shift lens



 
 
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  #31  
Old February 9th 09, 10:36 PM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
John A.[_2_]
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Posts: 1,551
Default Faking and expensive tilt-shift lens

On Mon, 09 Feb 2009 11:19:49 -0800, nospam
wrote:

In article , John A.
wrote:

On a Bayer-filtered sensor 1/2 pixel = 1 photosite.


that's incorrect.


You're right. That should have been 1/4 pixel instead of 1/2. I was
thinking one-dimensionally. See my other post, though, for further
clarification and correction of my thinking.
  #32  
Old February 9th 09, 11:09 PM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
ASAAR
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Posts: 6,057
Default Faking and expensive tilt-shift lens

On Mon, 09 Feb 2009 21:34:29 GMT, John A. wrote:

And a pixel IS made of 2x2 photosensors on a Bayer-filtered sensor
array. The sensors are arranged something like this:

G R
B G

Together, those four photosensors make up one pixel.

Ahhh... But I think I see what you're talking about. That's in a
single-exposure Bayer system. In the theoretical four-exposure system
we are discussing we would get four three-color synthesized pixels
from each 2x2 Bayer array. (Minus a row and a column for the image, I
believe, assuming we'd only keep the overlapping portions of the four
exposures.) That was what you meant, right?

So maybe we both get it, and don't get it. =D


Gotcha! But no, the
G R
B G

photo sensors don't make up one pixel. If they did, then a 12mp
sensor would have 48 million little silicon RGBG thingies. Some
advanced amateurs have been known to physically remove the bayer
filter, using powerful solvents to dissolve it. A de-Bayered 12mp
sensor then becomes a monochrome 12mp sensor, not a 48mp sensor.

In a way, the Bayer filter cheats a bit. The intensity of each
colored pixel is calculated by interpolating (demosaicing) the value
of the light that it registers as well as that of the differently
colored pixels that surround it. The result isn't 100% accurate,
but it's more than good enough. Seeing is believing!

  #33  
Old February 9th 09, 11:35 PM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
John A.[_2_]
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Posts: 1,551
Default Faking and expensive tilt-shift lens

On Mon, 09 Feb 2009 17:09:50 -0500, ASAAR wrote:

On Mon, 09 Feb 2009 21:34:29 GMT, John A. wrote:

And a pixel IS made of 2x2 photosensors on a Bayer-filtered sensor
array. The sensors are arranged something like this:

G R
B G

Together, those four photosensors make up one pixel.

Ahhh... But I think I see what you're talking about. That's in a
single-exposure Bayer system. In the theoretical four-exposure system
we are discussing we would get four three-color synthesized pixels
from each 2x2 Bayer array. (Minus a row and a column for the image, I
believe, assuming we'd only keep the overlapping portions of the four
exposures.) That was what you meant, right?

So maybe we both get it, and don't get it. =D


Gotcha! But no, the
G R
B G

photo sensors don't make up one pixel. If they did, then a 12mp
sensor would have 48 million little silicon RGBG thingies. Some
advanced amateurs have been known to physically remove the bayer
filter, using powerful solvents to dissolve it. A de-Bayered 12mp
sensor then becomes a monochrome 12mp sensor, not a 48mp sensor.

In a way, the Bayer filter cheats a bit. The intensity of each
colored pixel is calculated by interpolating (demosaicing) the value
of the light that it registers as well as that of the differently
colored pixels that surround it. The result isn't 100% accurate,
but it's more than good enough. Seeing is believing!


Dissolving the filter doesn't change the circuitry and firmware. The
camera still interprets the 2x2 sensor array as one pixel.
  #34  
Old February 10th 09, 02:10 AM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
nospam
external usenet poster
 
Posts: 24,165
Default Faking and expensive tilt-shift lens

In article , John A.
wrote:

On a Bayer-filtered sensor 1/2 pixel = 1 photosite.


that's incorrect.


You're right. That should have been 1/4 pixel instead of 1/2. I was
thinking one-dimensionally. See my other post, though, for further
clarification and correction of my thinking.


i figured that's what you meant and it's still wrong.
  #35  
Old February 10th 09, 02:17 AM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
nospam
external usenet poster
 
Posts: 24,165
Default Faking and expensive tilt-shift lens

In article , John A.
wrote:

Gotcha! But no, the
G R
B G

photo sensors don't make up one pixel. If they did, then a 12mp
sensor would have 48 million little silicon RGBG thingies. Some
advanced amateurs have been known to physically remove the bayer
filter, using powerful solvents to dissolve it. A de-Bayered 12mp
sensor then becomes a monochrome 12mp sensor, not a 48mp sensor.

In a way, the Bayer filter cheats a bit. The intensity of each
colored pixel is calculated by interpolating (demosaicing) the value
of the light that it registers as well as that of the differently
colored pixels that surround it. The result isn't 100% accurate,
but it's more than good enough. Seeing is believing!


Dissolving the filter doesn't change the circuitry and firmware.


true.

The
camera still interprets the 2x2 sensor array as one pixel.


where did you get that idea? have you been reading sigma/foveon
propaganda a bit too much?

they are definitely not taken in clumps of four. not only would that
would look like ****, but it would resolve a whole lot less than they
do now.
  #36  
Old February 10th 09, 02:36 AM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
ASAAR
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Posts: 6,057
Default Faking and expensive tilt-shift lens

On Mon, 09 Feb 2009 22:35:34 GMT, John A. wrote:

Dissolving the filter doesn't change the circuitry and firmware. The
camera still interprets the 2x2 sensor array as one pixel.


Cutting to the chase, you're rapidly starting to appear dense as a
post. Do you not understand that each of the sensels in that 2x2
array is used multiple times in several other 2x2 arrays? Put
another way, if you have a sensor containing 4mp photosites, where
the Bayer CFA covers 1 meg with red filters, 1 meg with blue
filters and the remaining 2 meg sensels with green filters, would
you say that it's a 1mp sensor or a 4mp sensor? If you choose to
become offended and not reply, thank heaven for small favors. You
can read this thread from current and previous rpd forum members
discussing this, but I doubt that you'll learn much from it.

http://www.burnyourbonus.info/rec.ph...hread2936.html


  #37  
Old February 10th 09, 05:34 AM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
Paul Furman
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Posts: 7,367
Default |AX| Faking and expensive tilt-shift lens

John A. wrote:
On Mon, 09 Feb 2009 17:09:50 -0500, ASAAR wrote:

On Mon, 09 Feb 2009 21:34:29 GMT, John A. wrote:

And a pixel IS made of 2x2 photosensors on a Bayer-filtered sensor
array. The sensors are arranged something like this:

G R
B G

Together, those four photosensors make up one pixel.

Ahhh... But I think I see what you're talking about. That's in a
single-exposure Bayer system. In the theoretical four-exposure system
we are discussing we would get four three-color synthesized pixels
from each 2x2 Bayer array. (Minus a row and a column for the image, I
believe, assuming we'd only keep the overlapping portions of the four
exposures.) That was what you meant, right?

So maybe we both get it, and don't get it. =D

Gotcha! But no, the
G R
B G

photo sensors don't make up one pixel. If they did, then a 12mp
sensor would have 48 million little silicon RGBG thingies. Some
advanced amateurs have been known to physically remove the bayer
filter, using powerful solvents to dissolve it. A de-Bayered 12mp
sensor then becomes a monochrome 12mp sensor, not a 48mp sensor.

In a way, the Bayer filter cheats a bit. The intensity of each
colored pixel is calculated by interpolating (demosaicing) the value
of the light that it registers as well as that of the differently
colored pixels that surround it. The result isn't 100% accurate,
but it's more than good enough. Seeing is believing!


Dissolving the filter doesn't change the circuitry and firmware. The
camera still interprets the 2x2 sensor array as one pixel.


The raw file has the separate bayer parts unmerged.

I'm not sure how a half pixel shift would work for increasing
resolution... perhaps you'd need to go 1-1/2 or 2-1/2 pixels.

--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam
  #38  
Old February 10th 09, 07:05 AM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
nospam
external usenet poster
 
Posts: 24,165
Default Faking and expensive tilt-shift lens

In article , John A.
wrote:

The
camera still interprets the 2x2 sensor array as one pixel.


where did you get that idea? have you been reading sigma/foveon
propaganda a bit too much?

they are definitely not taken in clumps of four. not only would that
would look like ****, but it would resolve a whole lot less than they
do now.


It makes more sense when you consider microlenses over multiple
sensors, actually.


that makes even less sense.
  #39  
Old February 10th 09, 05:09 PM posted to aus.photo,rec.photo.digital,rec.photo.digital.slr-systems
mcdonaldREMOVE TO ACTUALLY REACH [email protected]
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Posts: 243
Default |AX| Faking and expensive tilt-shift lens

Paul Furman wrote:

Dissolving the filter doesn't change the circuitry and firmware. The
camera still interprets the 2x2 sensor array as one pixel.


That's incorrect. The algorithms used to determine pixel values
actually look at MORE than a 2x2 array! They try to determine, for example,
if an edge runs through a pixel. If it does, they use other
parts of the two sides ... outside a 2x2 array ... to try to determine
all three RGB values of the pixel. The algortithms are nonlinear ..
they do not merely interpolate. They actually GUESS.


The raw file has the separate bayer parts unmerged.

I'm not sure how a half pixel shift would work for increasing
resolution... perhaps you'd need to go 1-1/2 or 2-1/2 pixels.


1/2 pixel increments would work.

Doug McDonald
  #40  
Old February 10th 09, 09:49 PM posted to rec.photo.digital,rec.photo.digital.slr-systems
Wolfgang Weisselberg
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Posts: 5,285
Default Faking and expensive tilt-shift lens

John A wrote:

G R
B G


Together, those four photosensors make up one pixel.


Sorry, your claim is as invalid as your email address.

-Wolfgang
 




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