At 01:54 PM 4/11/2002 -0400, you wrote: >Having entered the equation into a spreadsheet, and played with the DOF >possibilities, it seems that, for making a very large print, in which I >might choose a smaller CoC, DOF gets very small indeed. What has been >your experience with apparent sharpness at 12x or 14x magnification.
Personally, I haven't seen that much perceptual impact on DOF from enlarging. To a degree, it's self compensating because people tend to view a larger image from further away, making it effectively smaller. My main problem has been that an image with just OK sharpness really shows up soft at 12 x 18. >Another question: Apart from working distance, is there any advantage to >using a 100mm or a 200mm lens? What about a wider lens, such as a 28mm >or 24mm, with an extender, as has been suggested here. Since I'm not >dealing with a flat object, do I really need a flat field lens? You get the same changes in angle of view and perspective with a wider lens up close. I like the 200mm because a tiny shift in my position can totally change the background. A wider lens would incorporate more of the background. If you want to show the pipe with other objects, a 50mm or wider might be worth while. At the magnification is not so great that you'll have unworkable working distance - a 35mm at 0.4 magnification would still give you ~100 mm working room. Cheers - MCC - - - - - - - - - - Mark Cassino Kalamazoo, MI [EMAIL PROTECTED] - - - - - - - - - - Photos: http://www.markcassino.com - - - - - - - - - - - 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 .
