I sold my 500mm f4.5 because it was too big and heavy for my purposes, to put it bluntly I did not enjoy hauling it around and found myself leaving it behind on most of my outings. I also found that the wimberley head required for the bigger 500 was too specialized, it was useless to my other lenses so I was also forced to bring another tripod and head around with me as well. I needed a bird lens that was a little less work to bring around with me and one that i could put on my BH-1 ballhead and get good results...enter the 400mm DO. I'v done alot of reading up on this lens and decided that I needed to get one in order to make a decision since opinions on this lens were so divided. After searching high and low for a recent used copy of the DO I finally found one, it was made in April 2005 according to the date code so it is a very recent copy.
This lens produces stunning images. I'v had a couple of L telephoto lenses and I can say with confidence that my copy of the DO is pretty much on par with them in terms of image quality, build and functions. This isn't consistent with what many other people think of this lens but my copy is great and it will deffinatly have a place in my gear bag for a long time. Here is a link to a photo I took with this lens PLUS a 1.4x TCII
http://img.photobucket.com/albums/v1...uk/kinglet.jpg
On this link you will find my bird gallery, almost every photo on it was taken with the 400 DO and the 1.4x TC combo
http://russjonesphoto.com/gallerybirds.html
I do find the huge variation in opinions a bit worrying though, it seems that there certainly are some copies that are better than others so perhaps a trial run before you buy might be a good idea. It seems the problem copies were 2002 copies and earlier but I really can't quantify this with any data.
Russ