Archived posting to the Leica Users Group, 2003/12/14

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Subject: Re: [Leica] Leica Digilux 2, again
From: Frank Dernie <Frank.Dernie@btinternet.com>
Date: Sun, 14 Dec 2003 14:20:29 +0000

The first statement can't be true Don, because if it were the image 
would not be focussed on the sensor but at infinity behind it. This was 
part of the BS Olympus were using in their marketing of the 4/3 system 
- - I notice it has been corrected recently. Certainly the further the 
exit pupil of the lens is from the sensor the lower the maximum angle 
of incidence but there must always be some rays non normal to the 
sensor surface, except axial rays at the center, for an image to be in 
focus. This max angle can be estimated from the angle between the edge 
of the rearmost element of the lens and the opposite edge of the 
sensor. This represents a worst case edge, always assuming the whole of 
the rearmost element is used at full aperture.
cheers
Frank


On Sunday, December 14, 2003, at 01:54  pm, Don Dory wrote:

> Frank,
> The last element probably brings all of the light rays perpendicular to
> the sensor.  Remember this camera was designed as a package so the lens
> is probably designed specifically with the exact CCD in mind.
>
> All of our hopes for a digital M probably will devolve into a 28-90 F2
> zoom with a 4/3's sensor.  You could probably arrange an electronic
> focus spot much like the exposure dots in an M7: an arrow on either 
> side
> of correct to tell you which way to focus.  The benefit would be a 
> clear
> viewfinder with no distracting patches.
>
> Don
> dorysrus@mindspring.com
>
> -----Original Message-----
> From: owner-leica-users@mejac.palo-alto.ca.us
> [mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of Frank
> Dernie
> Sent: Sunday, December 14, 2003 4:27 AM
> To: leica-users@mejac.palo-alto.ca.us
> Subject: Re: [Leica] Leica Digilux 2, again
>
> So much for all the bullsh*t about angle of incidence at the sensor
> then eh! If the last element is almost touching the sensor the angle of
> incidence will be very large unless, I suppose, the periphery of the
> lens element is not used but then why would it be there?
> Frank
>
>
> On Sunday, December 14, 2003, at 08:16  am, Eric Welch wrote:
>
>> A MUCH shorter focal length. And have you seen the diagram of the
>> internals of the Digilux2? The last element is almost touching the
>> sensor. With longer focal lengths, and a shutter in the way, you have
>> your answer.
>>
>> On Dec 13, 2003, at 9:56 AM, eric wrote:
>>
>>> The body and lens dimensions look so very M rangefinder.
>>> So again - Why can't they design a digital M body?
>>> I know it has been discussed at length about angles of incidence and
>>> sensors
>>> not up to the task - but what is so different about the digilux 2
> that
>>> precludes designing a body to accept M lenses?
>> Eric
>> Carlsbad, CA
>>
>> 'Never ask a man what computer he uses. If it's a Mac, he'll tell you.
>
>> If it's not, why embarrass him?'"  - Tom Clancey
>>
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