Canon EF 100-400 f/4.5-5.6L IS II USM First Impressions Review
I received my 100-400mm MkII this morning on a gray dismal day, but was anxious to get out with it and I had time, so I put it on the 1D4 for familiarity, pocketed the 1.4x II just in case, and off to the beach I went.

AutoFocus: Let's start with one of the most important factors for a lens in this category. Unfortunately, for me as a birder, today I was not given an opportunity t use it on birds in flight. That said, the lens offers a very strong impression indeed for all focusing tasks I asked of it today. At the risk of being too enthusiastic I must say that This lens is the fastest most accurately focusing lens I have had opportunity to shoot.*
Okay, so two weeks later and with a good deal more time with the lens, I feel I need to clarify.
In many situations, it is the fastest, going from infinity to near.
It s also very accurate, giving me more keepers than the previous version or any previous zoom I have used.
What have a noticed that changes my initial impression? With birds in flight it is a monster, amazing. and yet, there is something missing. It could be I'm rusty (really, I am) but when I shoot with the 500mm Prime, one of it's abilities that I simply can not explain is it's profound need to always achieve focus on the subjects eye. I don't understand why this happens so effortlessly, but it does. Even with it's much narrower DOF, it appears to pull this off better than the new 100-400mm.
I can not quantify this. It really is like magic on the 500mm, but I have round the world photos that show this. With the 100-400mm I am more likely to get a wing tip or body part.
One more disclaimer, I have not MFAd this new lens yet.
On the 1D4 and 5D3 side by side it has mopped the floor with the otherwise amazing 200mm f/2L! Quicker, quieter, and more confident. In fact the assertion with which this lens snaps into correct focus is absolutely unequaled. Dead silent, it is a quick "snick" sound then it's in focus. I've never seen anything like it. Going from near infinity on a distant house peak to the tree 3 feet in front of me offers ZERO hunt, just the brief blur as it travels from all the way out to nearly all the way in and solid perfectly accurate lock.
It is absolutely faster than the 400mm f/5.6L prime.
It also bested the 200mm f/2 indoors in low light for af speed and lack of hunting on both 1D4 and 5D3.
I am quite sure that when I do the side by side, it will be faster than the 500mm f/4L IS (v I)
(it is)
Folks, I did not believe it was possible for a zoom to focus so fast and confidently. Canon has really made some significant improvements with the MkII designs.
Tracking on the 1D4: I have yet to be able to test it on birds in flight, but it tracked my dogs running through the tall beach grass as well as or better than the 400mm f/5.6L prime.
1.4X T-Con: I tried out the 1.4x MkII when the light was good and the AF did not seem to slow or lose accuracy. This is better than the results I get from any other zoom I have tried, besting the 70-200mm f/2.8L IS (VI) and better than most primes.
Minimum Focus Distance: At approx 3" 6" it is nearly half what the MKI gave us with it's already impressive and useful 6 foot MFD. Compare it to the 400mm f/5.6L prime and it's a shocking upgrade for those that are not always shooting things at long distances. This feature literally multiplies the magnification (and overall flexibility) of this lens over it's predecessors.IMAGE LINK: http://jakehegnauer.zenfolio.com/p605089996/e24a86118


IMAGE LINK: http://jakehegnauer.zenfolio.com/p605089996/e4957bf97

Image Stabilization: Once again, it appears to be the best I have had opportunity to use. It is fast to engage and quieter than any other IS system I have used, besting the 500mm f/4L IS, and 200mm f/2L IS handily. I was shooting @ f/16 to get 1/10th of a second shots hand held and was rewarded with dead on sharp images. This IS system will be a lifesaver. Clearly one of the best implementations available and LIGHT YEARS ahead of the 1st Generation IS that is installed in the older MkI 100-400mm.
Image Quality:
Well frankly again I am amazed. I have not had opportunity to use the new MkII 70-200mm, or the 70-300mm L, but I have seen images and heard a lot of good things. Clearly this lens is in that class of new "primelike" zooms. It is a significant improvement over the VI 100-400mm and any other zoom I have shot with other than ones costing much more.IMAGE LINK: http://jakehegnauer.zenfolio.com/p605089996/e2ab3c07f

For the pixel junkies, here are some 100% crops and a link to what I have uploaded so far.
(NOTE: The un-cropped images I have uploaded were in camera small jpegs from the 1D4. The crops are taken from RAW files with everything zeros to default using Capture 1 v7)
http://jakehegnauer.zenfolio.com/p605089996

GrommettIMAGE LINK: http://jakehegnauer.zenfolio.com/p605089996/e308359c8

100% crop with detail of fur. This is ISO 200 f/5.6 IMAGE LINK: http://jakehegnauer.zenfolio.com/p605089996/e3f9e389e

Portrait lens replacement? 135mm f/5.6IMAGE LINK: http://jakehegnauer.zenfolio.com/p605089996/e3f2d416e

Handling:
It weighs a bit more than the VI, more along the lines of a 70-200mm, and certainly feels more "beefy" than the VI. The focus ring is smooth and placed for ease of access (too easy?, more on that later)
All the usual switches are there and within reach, with some additions over the previous model including additional IS modes.
Zoom Control: Well, this review had to have some detraction, and this is the biggest one. To those of you that have read my posts on this forum it may come as no surprise that the switch from the "one touch" push pull zoom of the VI to a rotating zoom mechanism is not going to go over well for me. Now the preference for rotating zoom vs. push pull is obviously a personal one. But preferences aside, it is also an impersonal fact that one touch zooming made the 100-400mm L IS VI the fastest lens available when it comes to accurately zooming to recompose. No rotating zoom can compete. And this where I question Canon's understanding of how THIS lens is used most. It is an action lens. And fast action is aided by the push pull zoom. Nearly (you'll see, wait for it) everything else about the changes made to upgrade this VII lens aid the action shooter. Speed all the way. The internals of the rotating zoom also = weight. This lens is heavier specifically because of this switch. Is it too heavy? No I will manage easily but again, I would have preferred the lighter weight of the VI.
And then there's that Tension Ring? I can just see the designers considering this feature. "Well the old one had it" And the old one needed it. It was a one touch "push pull" zoom. What on earth do we do with the tension ring on a twist zoom? The zoom ring as it is , is a bit on the stiff side when you open the box. I am sure it will soften up, in fact today I already was aware of it,. but I just can't see the need for this tension ring.
And as some others have mentioned, in it's current state of stiffness, I could not use it as a push pull in a way that was smooth enough to use.
Lens Collar: So what else is NOT an improvement for the intended use of this lens? The non removable lens collar. The things is very well designed. The removable foot as a concession works well, and as a built in part it rotates smooth as a dream in its built in collar just like the big primes. I like the idea and execution, but .. and here's that question for Canon re: intended use. "Just who do you think it going to use this new feature?"
On THIS lens it makes no sense. Give use the removable collar and 98% of us will put it in the box upon receipt of the lens and never use it again. This is a HAND HELD lens and is was in no urgent need to have an improved rotating collar, let alone one I can't just take off.
The Hood: It works like any other hood with the addition of the little window to allow you to adjust a rotating filter like a polarizer without having to remove the hod. Nice.
In Summary:
This is the new Must Have action zoom lens for all manner of subject matter. Wildlife and sports, anything that you do in the great outdoors that requires fast auto focus, good zoom range and 400mm max focal length. This is the new standard.
Superior image quality in a flexible zoom, that has some of the best Auto focus and IS ever installed in a lens.
Excellent compatibility and useability with a 1.4x T-Con makes it even more flexible.