John,
Usually, lenses optimized for digital claim to have a large rear element.
Olympus explains this way the reason for their large bayonet and many think
that Canon has an edge over Nikon for the wider EF mount over the narrower
F. In this case of 2mm between the rear element and the sensor, I'd suggest
you think of the rear element (or group) of the R-1 as a meniscus with a
curved surface toward the other elements, acting as a focus plane for the
rest of the lens + a flat surface toward the sensor, for conveying the image
perpendicular on the sensor. Just an idea.
Dario
----- Original Message -----
From: "John Francis" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, September 09, 2005 7:10 PM
Subject: Re: First non DSLR digicam with 10MP APS sensor- contradiction
On Fri, Sep 09, 2005 at 06:07:37PM +0200, Dario Bonazza wrote:
Isn'it it possible that a large rear element force rays perpendicular to
the sensor? This will allow a better image on the sensor and if such an
element is part of the lens design, it won't affect lens performance.
No. To a first approximation light rays from every part of the rear
element contribute to every point of the image. The larger the rear
element, the wider this cone of rays is, and so the more deviation
there is from the perpendicular (and the wider the range of angles,
which makes it hard to compensate by angling the sensor pits).
