> > The *ist D's sensor has about 43% of the area of a 35mm film frame (369 > square mm compared to 864 square mm). Lenses don't have infinite > resolution; instead they have resolution limits for each aperature. Does > it follow that a 35mm film lens' resolution, when used on the *ist D, will > be 43% of its resolution on a 35mm film camera? (And conversely, that its > resolution on a 35mm film camera would be 234% of its resolution on the > *ist D?) > If a given DA lens were to be as similar as reasonably possible to a given > 35mm lens, with the sole exception that it's image projected the same > resolution onto the smaller area of the *ist D's sensor, would the sensor > be able to capture 234% as much resolution as it would with the 35mm film > lens? This doesn't sound right.
> If a very sharp lens, such as Pentax's sharpest 50mm lenses (past or > present), loses 57% of its resolution when used on the *ist D, is it still > a very sharp lens? The photos produced can be very sharp. Pros don't seem to bitch about image quality from APS-sized Nikon sensors or slightly bigger and smaller Canon sensors. > I plan to get an *ist D soon no matter what answers I get to these > questions. I'm just wondering what the potential is for DA lenses, all > else being equal, to be sharper on the *ist D than 35mm film lenses. The Nikon versions of DA seem to do very well. While I think the entire concept of an APS-sized sensor is misguided, lens designers seem to be able to cope with the new challenges fairly well. All other things are not equal, unfortunately. A digital sensor has different properties and particularities, and lenses designed for digital are likely to work better for digital than those that are designed for film, no matter what the format is. Some very good "film" lenses have weaknesses that are tolerable for film use but cause real problems on digital. What will make things interesting is if companies start making lenses in the normal 35mm format (not pentax DA or nikon DX) that are optimized for performance on digital and perform WORSE on film! DJE
