I was reading the 20+ Tips article (December 2007) and have a question about the number 5 tip. I took a look at some of my photos. I have a Canon 5D. When comparing two shots of the same subject one was sharp the other much less in focus. I compared what I thought was the file size which was 4368x2912 pixels for both photos. What exactly was this tip referring to? All my photos sharp or not are as I stated 4368x2912 at 72 resolution, 60.667x40.446 inches 36.4MB.