William wrote:
>First, is it really true that this is just a semantic issue? That is, does >one properly talk about "depth of field" only of the negative, and >"sharpness" only of the print? Are those generally accepted definitions? If you have, say, two 35mm lenses, one sharper than the other, both shooting the same subject at the same aperture. Would you say that the sharper lens has more DOF? Of course not. DOF is the relationship between whats in the plane of focus and the areas on both sides of that plane. If you blow up an image reduced sharpness from the same viewing distance will affect all parts of the image equally so that the relationship will hold regardless of what you do with the image. DOF is mathematically obtained. What kind of sharpness you find adequate for DOF is a subjective issue and this is sharpness. You don't reduce the sharpess of an image while increasing magnification. You are decreasing sharpness for a certain area while magnifying but in total the sharpness is constant. P�l - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
