Archived posting to the Leica Users Group, 2004/10/01

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Subject: [Leica] Re: RE: Digital R-Module - hands on
From: jcb at (JCB)
Date: Fri Oct 1 09:17:07 2004
References: <> <> <>

At 04:29 PM 9/30/2004, Adam Bridge wrote:

>I thought there wasn't going to be a low pass filter in the digital R?
>Has that changed? Did I miss it?

You cannot use high resolution lenses on a digital sensor without a low 
pass filter. The Nyquist problem is a fact of nature. You cannot sample a 
10MHz signal with a 2MHz clock. Artifacts galore if you try. The missing 
info cannot be completely added (interpolated) later. The gaps are too large.

They may claim that no low pass filter is used, but you can bet your boots 
that some sort of mechanism is used to reduce the lens resolution to more 
match the resolution of the sensor. It's a fact of physics. Miss matched 
frequencies must somehow be matched.


In reply to: Message from attinasi at (Marc Attinasi) ([Leica] Digital R-Module - hands on)
Message from jcb at (JCB) ([Leica] RE: Digital R-Module - hands on)
Message from abridge at (Adam Bridge) ([Leica] RE: Digital R-Module - hands on)