On 9 Jun 2004 at 20:53, William Robb wrote: > I think the 77 has very strong micro contrast, for lack of a better > term. It seems to see very fine differences in tone, which is what > minor skin blemishes are. > Interestingly, on the istD, the 77 is just fine as a portait lens. I > suspect that the local contrast properties of the lens is lost on the > lower bit depth available from the digital camera.
All the really sharp high contrast glass I have display similar renditions when used on the *ist D. I think the softening of the 77mm when used on the *ist D is more a function of the demosaic algorithm and absolute pixel pitch than the absolute bit depth per pixel, John Francis might be able to further elaborate? The image file that comes out of the camera has nearly one RGB pixel for every R, G or B pixel of the actual sensor. So I suspect the interpolation of the intermediate luminance and colour values is where the information is lost. In simple terms I guess if the algorithm tries too hard to make the value up you end up with the "digital look" Cheers, 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
