On 8 Jun 2004 at 17:39, Dario Bonazza wrote: > No, no. My comments are not based on your comment on the F 70-210 lens. > They come from 6-months experience with the *ist D and being disappointed > in seeing 4-5MP digital compacts allowing larger prints. > > *ist D folks, do you want me to shock you all? > > I resized that DA 14mm picture down to 4MP and saved it as best jpeg > (Photoshop quality=12), then I closed the file for being sure not to retain 6MP > info in Photoshop memory. Then I opened the 4MP file again and I resized it up > to 6MP. You can find the result here:
Hi Dario, I'm not sure what you are trying to prove given your method and selection of test image and I'm not so sure why you are so surprised as to the results. Firstly in order to reduce a 6MP+ image to the pixel dimensions of a 4MP image the linear dimensions need to be reduced to about 83% so that equates to discarding less than one in five pixels in each dimension. This means that if the image is not very sharp and has no sharpening artifacts you're likely not see a difference in the before and after images. Have you done similar test with high quality 4MP images? If the results of such an experiment are similar to the previous one you made with the 6MP images where does that leave us :-) So in order to alleviate further misdirected energies towards non-existent sharpness problem of the *ist D I've made my own test which I believe will prove its self. I used a source image shot by myself using the 31mm LTD (the non-green image that I posted earlier) which was saved as best quality JPG in camera with minimum in-camera sharpening and contrast and average saturation. http://members.ozemail.com.au/~audiob/temp/EXIF.gif I simply reduced it's size to 83% then enlarged it again to it's original dimensions within PS (using best quality bicubic interpolation). I then saved the result as a loss-less file. I compared these two images side by side in my image browser (Thumbs Plus) at 3x magnification and made the following screen shot: http://members.ozemail.com.au/~audiob/temp/test.jpg Now have a guess at which side was the original? I'll give you a hint, it's the one that's lost resolution :-) I hope my point is made, if not then we obviously have a very different understandings and expectations regarding digital imaging. 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
