RE: filmscanners: NIKON LS 4000 AND D1X

[Paul Chefurka <Paul_Chefurka@pmc-sierra.com>]

Let me guess.  They'd be bigger, heavier and more expensive?  Given that the 
performance of 35mm lenses over their entire field is at least adequate these 
days, I can't see that there'd be a lot of advantage.

I've seen this "sharper in the center" argument raised before wrt digital 
sensor arrays.  My question is - given the inherent resolution limits of such 
arrays, does this argument hold any water?  I can understand that you might get 
less fringing and other aberrations in the center, due to the oblique paths of 
the light rays in the image corners.  Resolution improvements near the center 
seem to be a red herring to me, though.  The resolution of most current sensors 
seems to be 100 pixels per mm, which translates into an absolute maximum 
resolution of 50 lp/mm.  Factoring in noise and the phase of the moon, a 
realistic upper limit for these sensors would seem to be about 40 lp/mm.  This 
is well below what even a half-assed consumer lens like a Sigma can put out.

So, while higher levels of contrast and lower aberrations in the center of the 
circle of coverage might be useful advantages, I don't think the argument of 
"sharper" as in higher resolution matters at all - at least at the current 
state of the art.

Paul


-----Original Message-----
From: Anthony Atkielski [mailto:atkielski.anthony@wanadoo.fr]
Sent: Monday, September 17, 2001 2:31 PM
To: filmscanners@halftone.co.uk
Subject: Re: filmscanners: NIKON LS 4000 AND D1X


Steve writes:

> But you do have the advantage that the centre is
> invariably sharper, often much sharper, than the edge.

If that is such an advantage, why hasn't anyone designed lenses for 24x36 that
cover a much larger area than the film frame?  The same logic would apply.