I still have the 100-400L but haven't used it since obtaining the Tamzooka (150-600). My copy is definitely on par or better IQ wise than the L and with the 5D MkIII it will focus just fine, AI Servo or otherwise. And this is compared to what I believe is a very sharp copy of the 100-400L. The only advantage that I can see with the L now is it's size, it will physically fit into many of my camera bags, the Tamron being about 1/3 bigger and heavier will not.
The Sigma 120-300 is mouthwatering but it's also incredibly huge and heavy. Almost as heavy as my 500L is and I've noticed that most owners admit to using a TC with it almost always, which narrows the gap between it and the 500L.
With the Tamzooka I find it very refreshing to have 600mm on a full frame camera. Beautiful files. I no longer want (as much) for more focal length and when that does occur of course, that's when I lug the 500L around.
Since getting the Tamzooka I haven't even used my 7D yet, but one day I will. There have been reports of it not focusing correctly, something I haven't verified yet. The files from the 7D just can't compete with either the 5DII or 5DIII. The angle of view, (perceived focal length), higher pixel density and higher fps are the only things going for it now.
I've used the 2XIII TC with my 70-200L II and the IQ is okay but the focusing is very sluggish. Really bad in dark forests, jungles or shadows, sometimes it won't lock focus if it's dark enough. I've only used it that way a few times when I was out in the field with the wrong tools for what I was trying to do, just a stop gap. The lens when used with the 1.4 II or III is very useful and functional, I use it that way all of the time.
If you are wanting to shoot birds and unless you have a blind set up extremely close to them, you will always lust for more focal length.
Just my 2 cents, and strictly imho.
Roger
ceriltheblade wrote in post #16718320
Sorry for the flippant title but...
I am interested in examining the 100-400 focal lengths...
and it seems that there are many people out there who have the canon 100-400 f4.5-5.6 L IS enjoy it.
and out of some of the other single lens options out there (e.g. the sigma 120-300 f2.8) it is the smaller and lighter option - though slower for sure.
and for the past 70 billion years there has been a rumor out there that a second version of this lens will be coming out...
and it will be a very small part of my photography (though one I miss)
and I am weighing getting the canon 70-200 f2.8 II
hence - I ask - assuming that "tomorrow" there is no new announcement of another 100-400 (ish) and assuming that I can afford the price point of a brand new retail 100-400,
would you all think that the lens is still "relevant" or would you just get a extender X2 III in the case that I indeed get the 70-200 II?
many thanks for opinions