To make a long story short - I had this lens for a while and it was a sharp copy. For some stupid reasons I sold it, missed it and bought another used copy on FM. This is one of the first shots using that new lens. I am pretty pleased how it performs at its longest focal length and at fully wide open... The first image is of the entire frame (well, it shows some vignetting and no adjustment was made for that but still not too bad) and the second one is a crop, not 100% but enough to show what this lens can do. This lens has been much maligned, at least at 400mm, but it is really not bad .

Don't think you can beat the 100-400 for the price, size and image quality.

I did about 1.5px high pass sharpening on this one. Sorry, I don't have the 100% crop.

Here's a few. This with an earlier copy (date code UR)

Canon 40D, ISO800, 1/320:

Handheld at 1/40 at ISO 400.

Here is one:

All handheld at 400mm f5.6 :

I find mine to be stunningly sharp wide open at 400mm, almost as good as the 500.

Here are two images, both taken handheld, both with the 1Ds3:

The first was taken with the 1.4x TC wide open at f/8

Wow, look at those images ! I am impressed with the IQ this lens can truly generate at 400mm and at wide open. Yet, there are people that think that this lens is only mediocre at those shooting conditons . Keep them coming, folks!

AGeoJO wrote:
Keep them coming, folks!

You asked for it

30D 400mm 5.6

I haven't used 100-400 for BIF in a long time. Kept these pics of the albino Peregrine Falcon because of the background......in effect they were BIF skill "calibration" shots.

Nello Milanese:
All handheld at 400mm f5.6 :

WOW. I am not taking away anything from the photographer but your copy of this lens is incredible! I never used mine at more than 380 mm and I still stopped it down.
My 70-200 f/4.0 L IS with 1.4 TC is sharper at 280 mm than 100-400 L was.

Three more BIFs: albino Dwarf Kestrel.

OK peter lets see an Albino Dwarf Golden Eagle

No more BIFs, some easy stuff here.

Great shots! I wish I hadn't sold mine.

PetKal:
No more BIFs, some easy stuff here

Peter, I always liked your "easy stuff". BIF are often missing interesting background

Ian.Dobinson wrote:
OK peter lets see an Albino Dwarf Golden Eagle

No problem, Ian. Comes out to feed at night only. Had to use a Better Beamer on him.

Thank you, Michael, I try to get appealing background for BIF images, however, as you know, them birds don't follow flight directions very well so one often ends up with a flying bird in an otherwise insipid picture.

This is a great lens. I regularly get shots in which a 100% crop wide open at 400mm is still sharp once a little sharpening has been applied in DPP.

It took me about a year to get used to using the lens though, in the first 12 months I actually wondered if I had soft copy!

Paul