Very very sharp, Too sharp actually at times.

weather sealing,

nice new locking hood design,

Improved IS over older versions, can really hand hold to 3 real stops under.

3D like rendering of subjects in circle of confusion ( Almost Pentax limited lens like )

great colour rendering and contrast

Faster AF

PRICE!

I don't know of Pentax patented it but a hood window to adjust polarizing filters or similar would be nice,

Strange bokeh, it's a bit harsh with back ground high lights and can make some hard yet still round halos. I'm comparing the bokeh to something like the Pentax 77mm limited or Canon 135mm F2L

Still a bit flare prone, even with the hood be careful with strong back lighting.

Heavy!, well this is normal for a F2.8 pro lens so start lifting weights.

It was time to move up from my 70-200 F4L and the older f2.8 version's were not an option due to their week performance at f2.8 so I bit the bullet. So far this lens almost stays permanently on my 5D MKII and it has earned it's money back several times over.

Shooting fashion shows or stage events is a dream with this lens now as it is super sharp right from F2.8, focuses faster and I can try for still shots in the far reaches of unlit portions of a runway or stage due to the better IS. On the note about IS do remember IS will let you shoot stationary subjects 3 ( realistically ) stops slower than with out IS but does not compensate for motion blur, something I keep forgetting on poorly lit runways. The lens also doesn't loose too much image quality with the 1.4x tc when extra reach is needed, a good thing as not to lug a 300mm around.

When shooting portraits the sharpness does becomes a double edged sword as almost every shot is now too sharp, needing softening and skin retouching. Nothing on a persons face escapes even when using as shallow a DOF as possible only getting the eyes sharp the lens will still pick up unwanted skin detail or makeup smudges. Also the Bokeh is just harsh at times. For fashion work this is a plus as designers love the extra detail it picks up in their clothing, the models can hate that all they want.

So far this lens is one of the best 70-200 f2.8 class lenses around, not perfect with a few touches left to get there but definitely in the top 3. I would love to see them some how soften the hard/harsh bokeh this lens can produce and with such a deep hood a filter window for would make this lens a dream in the field.

Overall despite the hefty price tag ( and weight! ) this lens is more than worth it for my needs, sharp and fast, built like a tank ( all "L" lenses are so ) and will probably permanently live on my camera unless I need to go wide. For everything it deserves a 5 out of 5 but I have to knock it to a 4 for value, come on Canon give you hard working customers a break in price.

Customer Service

Not need for the lens yet but Canon has treated me well with service and warranty repairs in the past.

Similar Products Used:

Canon 70-200 F4L, Pentax 50-135 F2.8 DA*, Nikon 70-200 F2.8 ( not the VR version ), Sigma 100-300 F4