T3D Re: T3D Re: digital camera resolution

[John Ohrt <johrt@xxxxxxx>]

John Bercovitz wrote:
> 
> Just taking the base numbers, I think there is something fishy here.
> Supposing we accept the guy's 40 lpmm in a 35 mm camera (fair if you
> have any depth of field) then the image has 24*36*40^2 or 1,382,400
> pixels.

2 pixels per line so:

24x36x80^2


>  If we take a 640 x 480 camera and throw in Nyquist

The Nyquist rules requires more than 2 pixels per line, to be precise.

Another point being routinely overlooked is that analogue (film etc) has
no directional bias while digital does. Usually the "digital" resolution
is quoted for best case ( horizontal or vertical lines). For lines at 45
degrees to horiz/vert, the resolution is degraded a further 30%.

If a digital image looks blocky, then you may not be optically limited
but sensor limited.  The analogue world makes it a little harder to pin
down the exact contributions of the many sources of blurring.

Dollar for dollar, I believe that scanning a 35 mm negative is the most
cost effective means of achieving resolution.

The market has many niches though and mercifully many products trying to
fill them.

I think Bill was saying that the digital cameras are good enough to be
real players in some niches.  I agree.

Regards,
--
John Ohrt,
Toronto * Ontario * Canada



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