Archived posting to the Leica Users Group, 1999/12/09
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I have just been looking at my first two rolls of Provia 100F (RDP III) slides. My own conclusion at this point is that the film is definitely not a quantum leap over the old Provia (RDP II)--in fact, I am not sure that it is an improvement at all. But I need to shoot the other 3 rolls I bought under more controlled conditions before deciding. In the meantime, I have been looking at the data sheets. I have seen some comments to the effect that the grain reduction in RDP III has gone too far, to the point of reducing perceived sharpness. Looking at the MTF graphs for RDP II and RDP III, one sees that the curve for the new film is flatter. Thus, at a frequency of 5 the response for both films is identical at over 100%. However, at 10 lp/mm the response of RDP II has dropped to 100% while RDP III is still above 100%; and at 20 lp/mm, RDP II is at 70% while RDP III is between 90% and 100%. Since these are the frequencies that determine apparent sharpness in a picture, doesn't this comparison imply that RDP III is sharper than RDP II? Or am I misreading the curves, and if so, what can one learn from the comparison? Nathan - -- Nathan Wajsman Overijse, Belgium General photo site: http://belgiangator.tripod.com/ Belgium photo site: http://members.xoom.com/wajsman/ Motorcycle site: http://www.geocities.com/MotorCity/Downs/1704/