Archived posting to the Leica Users Group, 2009/09/09

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Subject: [Leica] Layers and Layers
From: mark at rabinergroup.com (Mark Rabiner)
Date: Thu, 10 Sep 2009 01:43:07 -0400

Much confusion over the past years in my mind at least and I bet at least
one other person on the LUG about the missing layer in front of the M8 which
made for the need for the use of pricy hard to get filters and coding with
magic markers  and reams and reams of unsnipped dialog on the LUG.
I?m sure somebody made an effort to straighten it all out but I never got it
straight.
So I?m reading this book I got for twenty bucks about how to use this Nikon
D200 camera I have. Having used it for 3 years. I now want to know how to
use it. It?s a magic lantern guide. Small. But heavy. Lots of clay in the
paper I think.  And unlike my missing manual which is missing:
Its involving. No jokes but nice side stories.
You'll never believe these people who work in the factory in Thailand...
Which is owned not rented by Nikon.

He talks about 4 different layers on front of the CCD of this camera and I?m
sure many other cameras.
Its a Sony by the way.
You shoot your Kodak I'll shoot my Sony.
 
First:
Is the low pass anti aliasing filter.
No Clark Kent no!
For the obvious reason of getting rid of fringing effects and moir?
patterns. I thought that was the missing culprit on the M8 but maybe not.
 
Second:
Infrared coating layer
Soaks up IR
IR is bad.
Creates perceived non sharpness
Reduced contrast
Color shifts
I thought that was the missing culprit on the M8 but maybe not.
 
Third:
Micro lens layer
As the sensor sites are more efficient grabbing light going right into them
at a perpendicular it needs this layer to aim the light straight in better
at the edges of the whole thing. For a Leica or a Hasselblad super wide this
layer would need to be super good as the edges are far away at an askew
angle if you catch my drift..  The glass is backed right up against the
sensor like one of those huge space ships over a small town. Half the list
and the real smart people too were saying such a thing was impossible we?re
going to have to live with a crop. I said with digital where there's a
will... I picked a winner on this one..
I always loved Kodak. They make me look good.
I thought they would have to invent this layer from scratch for a full frame
M.
Didn't know it was already long part of the sandwich.
They just had to made it a bit better at the edges.
No new technologies.
Piece of cake. And eat it.
 
Forth:
Bayer Layer.
Really called the Bayer Patterned filter but I?m calling it the Bayer layer
because I?ll remember it and so will you.
This is Red Green and Blue filters in a Bayer pattern because
CCD sensors do not see in color.
It is named after its inventor.
A guy who went by the name of Mr. Bayer.
He got a splitting headache then invented this:
http://scien.stanford.edu/class/psych221/projects/07/demosaicing/bayer_cfa.J
PG
 
So those are the four layers.
Low Pass
IR
Bayer
Micro lens

Your mileage my vary

I'm printing this out and putting it under my pillow you can test me in the
morning. After my decaf.
 
Layers of a Big Mac?
?Layers of the Big Mac buns are called the crown, the club and the heel.?

And the Bayer Layer. For later.


Mark William Rabiner