hi, what your saying is not clear ( no pun intended ) to me. The reason I say this is because it's a known fact that the digital sensors are intolerant of certain optical designs that film can tolerate with no abberation. There is also the issue of the fact that digital and or digital APS lenses are optimized for maximum image quality on the sensor, not highest possible image quality on film and or across the full 24x36 frame.
Since film is far higher resolving power than current 6Mp APS sensors did you shoot on fine film and digital with same lenses and compare the APS cropped film image to the digital image? Or did you just compare the typical results of one lens on digital vs another lens of same focal length on digital? I am not saying you did anything wrong in your testing and analysis but evenness of sharpness across the frame is not solely a good indicator of quality unless the the corners are actually sharper on the more even lens. Very often just the opposite is true and the lens isnt really more evenly sharp across the frame its just not as sharp as the lens with more difference in it's center performance. Wide angle lenses used on formats smaller than designed for typically exhibit this characteristic. for example if you use wide angle lenses designed for 8x10 cameras as a normal 4x5 lens, you end up with softer but more consistant performance across the frame than a true non wide angle 4x5 design gives. Except for very narrow angle telephoto or really long lenses or really low resolution media you should see usually more sharpness in the center because that is how lenses behave, the greater angle of deflection/incidence, the greater aberations become and resolution drops. Of course the better lenses minimize this but not a the expense of overall resolution.... JCO -----Original Message----- From: Herb Chong [mailto:[EMAIL PROTECTED] Sent: Sunday, September 18, 2005 9:10 PM To: [email protected] Subject: Re: Pentax K 2.5/200mm lenses which were adequate or better on film turned out to be inadequate on digital. they generally were not sharp enough for me to continue using, although in the case of the FA* 24/2, the chromatic aberration got way out of hand on digital. top quality lenses when used on film generally remained top quality on the *istD. many that were very good became acceptable or worse. some stayed acceptable. none ever got better. i got rid of any lenses that had too much difference between center and corner sharpness. also sold ones that showed too much falloff wide open too. Herb.... ----- Original Message ----- From: "J. C. O'Connell" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, September 18, 2005 8:53 PM Subject: RE: Pentax K 2.5/200mm > And also are you trying to say the sensor is revealing > the lens to not actually be as good as reviewed or are you saying the > sensor is inferior to film with regards to the range of optical > designs it can handle without sensor induced artifacts?
