skipwilliams@xxxxxxxxx writes:
<< Canon, Fuji, Contax, and Nikon THAT. I guess that those manufacturers are
all full of it because they offer digital bodies that can use supposedly
inferior 35mm lenses?
Skip >>
Interestingly you actually may need inferior lenses with the current crop of
digital cameras! This is because the digital pixel/sampling introduces moire
(or more correctly in digital signal processing speak aliasing) For example
the latest Nikon D1 "pro " camera which takes the old 35mm camera lenses has
the following sales pitch:
>> Just in front of the CCD is an ultra-thin lithium niobate (LiNB) low-pass
filter which acts as an anti-aliasing device and also cuts infrared rays.
This makes for a smooth tonal range and almost no moiré detectable in the
captured images.
<<
A "low pass filter" is a way of saying that the detail of the picture is
reduced (smeared/blurred) so that the finest detail covers more than 1 pixel.
This reduces aliasing but clearly the lenses ultimate performance is not
being realised. Now in the D1 the total sensor area is only about half of the
35mm format so some additional signal loss occurs which may be mitigated by
the generally lower performance corners of the lens/frame being excluded.
In other words here they are admitting that the 35mm lens has too high a
performance for the pixel size of the sensor being used and that they had to
degrade the lens resolution to avoid moire!
Regards,
Tim Hughes
>>Hi100@xxxxxxx<<
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