On 26 Jan 2004 at 15:56, J. C. O'Connell wrote: > At around 50 lp/mm which is a typical lens, the improvement of FF > vs > APS is about the same using either sysres equation, roughly a 50% total > resolution > improvement via FF over a APS size 6 Mp sensor. You can also see that when > using > really good lenses of over 130 lp/mm, there is little to be gained (less > than 10%) > in total resolution by using a FF sensor assuming the second (squaring) > sysres equation > is correct.
Where your proposition goes askew is in assuming that a typical lens offers an aerial resolution of only 50lpmm, good lenses can provide 500lpmm plus at wider apertures. Consider the Rayleigh limit which is the absolute resolution limit of a lens due to diffraction. Some camera makers provide a low pass diffracting filter in front of the sensor to limit aliasing at high spatial frequencies (although I don't know if this is the case with the *ist D). Plus you'll find that other factors (such as the filtering in the bayer interpolation algorithm) serve to provide a lower than theoretical limit to the total system resolution. Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
