By the way, I like the brief reviews and more detailed discussion of lenses on Lensrentals.com website.
One reason I value their opinions is that they see many copies of any particular lens... have multiple copies, sometimes dozens, of any given model in stock.... and have the opportunity to compare them closely with many other similar lenses from other manufacturers. Also, their lenses likely don't have an easy life... spend a lot of time bouncing around in the back of a UPS truck, and as rentals likely don't get the same care by users, as they would give their own lenses. Lensrentals also test their lenses after each is returned, tear them down to see what makes them tick, and regularly have them serviced. All this adds up to pretty good info about a lens.
Roger at Lensrentals.com sounds like a big fan of the original 100-400mm. Up front he admits it's not as sharp a lens as some primes.... it's a compromise. But he calls it a "very good compromise" that often ends up in his bag instead of several "better" primes for all the conveniences the zoom offers... a single lens covering a variety of useful focsl lengths.
He also likes the push/pull zoom. Some people love, others don't... I'm afraid I'm in the latter category, but to be fair that's a bias from similar design zooms in the past, not the 100-400L specificially. There is no doubt that the push/pull zoom is fast and with quickly moving subjects can make the difference between getting the shot or not. It's been a popular lens for airshows and birds in flight, in particular.
Roger notes that he 100-400L isn't its sharpest wide open... recommends using it one stop (or more) down from wide open, when image quality is critical... so instead of f4.5 at the 100mm setting, use f7.1... and instead of f5.6 at the 400mm focal length, set f8 or slightly smaller. (Again, for best IQ avoid f22, f32.)
What Roger is actually doing is managing his expectations and working within the limitations fo the lens, to get the very best he can out of it. This is similar to what I mentioned earlier, about not evaluating image sharpness and focus at 100%, since that's equivalent to ridiculously large prints. Back off to 25 or 33%... that's more realistic and closer to the largest size most of us will ever print an image. Your images look pretty good at more reasonable sizes.
If you test the lens, Micro Focus Adjust it yourself, or end up sending it off to have it calibrated, and are certain you've fully figured out and are using the best techniques with it to maximize image quality... But still aren't satisfied... Well maybe you should consider switching to another lens or two two or three or four.
For example, you might expect more from primes (for one thing, they can be more precisely Micro Adjusted on a 5DII)... If you don't mind carrying around and swapping out between 100/2.0, 200/2.8L, 300/4L and 400/5.6L, there's little doubt that... used right... those lenses may give you the results you're after.
Even better, EF 100/2.8 macro (tho a bit slower focusing), 200/2L II, 300/2.8L II and 400/4 DO II or 400/2.8L II would give you some of the very best image quality available from any lens made by anyone, ever. Of course, you might need to hire a Sherpa to help carry them around. And you'll have the equivalent of the cost of a small car invested in them.
Or maybe you should look at upgrading to the new 100-400L Mark II. It's sharper, especially at notable wide open and in the corners of images. Likely a lot of this is thanks to the addition of fluorite to the optical formula (which you'll also find in some other top performing Canon teles... such as the EF 70-200/2.8 II, 70-200/4 IS, and most of the "super tele" primes). It's also got even better IS and slightly faster focus. However it's now a two ring design, rather than push/pull (either a good thing ro a bad thing, depending upon how you feel about push/pull zooms). And it's a little bigger. And it's more expensive.
Or, rein in your expectations... Stop "pixel peeping" unnecessarily and evaluate your images in sizes more like you'll actually be using them. When I look at your photos as they might print 13x19 or even 16x24... They look pretty good to me! (P.S. Try enlarging that point-n-shoot's files that you think so highly of to 60" wide and see how they compare!)
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER
