OK, hang on Daniel,


Your confusing me........ again. LOL


According to the DOF calculator my distance of acceptable sharpness increases with:


1) increased aperture (i.e. larger number = smaller iris)


2) increased camera to subject distance


Let's say the subject is yardstick laying on the ground. My camera is on a rail 45 degrees to the ground plane. I am focusing on the 18" mark with center focus point.


At10ft awayI take a photo ofthe subject using 100mm at f4, I should get the same distance of acceptable sharpness as if I had taken the same photo from 5ft away with a 50mm at f4. Themaindifferencesare the field of view and the amount ofbackground blur. This distance on a 5D FF is .71 ft for both shots. So I see the middle 8-10" of the yardstick in acceptable focus.


So what happens when I takea photo from 10ft away with a 50mm at f4?The distance(or depth) of acceptable sharpness is now 2.97ft. I see almost all of the yardstick in acceptablefocus, do I not? The difference is that the yardstick appears half the size in the frame as the other two images.


That's easy to remedy. I just crop the image in half. It goes from 3000 pixels to 1500 pixels. The yardstick now appears to be correctly porportioned in the frame.


The yardstick also appears to be almost completely in focus unlike the other two shots.


What an I missing Daniel? and I mean that respectfully and sincerely.......


Chuck