So I have been using two A480s on my book scanner for over a year, they have shot several thousand pages apiece. Recently I noticed that the right side on both cameras is getting a little more blurred than it has in the past. This means that the top of the page for even pages, and the bottom of the page for odd pages are getting a little less crisp. I checked over just about everything that I think could be the cause. My lights are positioned well with even coverage over the whole page, in CHDK the cameras have a fixed subject distance value, they are very close to square with the page etc. etc.
Here is a sample of an even page:
Notice that at high magnification the word "Introduction" at the top is decidedly less in focus than the words in the middle of the page. Notice particularly the serifs on the letters "N" and "D."
Here is a sample of a processed odd page:
Notice that in the footnote text at the bottom there is a lot of breaking in rounded letters like "o," "c" and the top of "e." Also notice that the accents in "Ï„á½¸ Î¼á½´ á½„Î½" are almost unreadable. Also notice that this variability in the font makes the file-size considerably bigger. Using Clearscan, a 300 page book is typically about 2-5 mb, but since this problem has started they are going up to about 15 mb.
Has anyone else had problems like this?
Could this be a function of the cameras wearing out over time?
Does anyone have any suggestions for how to mitigate the problems?