How good is a canon 70-200 2.8 is with extenders ?

Mk1Racer wrote in post #10245761
Check this thread for some of my shots w/ a 70-200 f/2.8L non-IS + Canon 2x TC Mk II.

It's my understanding that the 100-400 will be sharper, but not by a whole lot. The thing is, for what a used 100-400 costs, I got my 70-200 f/2.8, Kenko 1.4x TC, and Canon 2x TC Mk II. To me, the added versatility is worth more than the slight trade-off in sharpness or IQ.

thanks for the link. Does Kenko extender have same quality as Canon?

Canon 2x extender cost $420 retail. This is ridiculous amount of money.

picard wrote in post #10245783
thanks for the link. Does Kenko extender have same quality as Canon?

Canon 2x extender cost $420 retail. This is ridiculous amount of money.

I have a Kenko Pro 300 DG 1.4x TC and I'm very happy with it. From what I've read, most folks are also pleased w/ the performance of this. I bought my Canon 2x TC Mk II used, for a little over half of what a new one goes for.

What I found was that if I stopped down while using the 70-200 + 2x TC, that the images sharpened up. You can see that from the pics in the thread that I linked to.

I honestly haven't shot many pics w/ the 70-200 f/2.8 + 1.4x TC, as I like the reach of the 2x TC. If it's to a point where I'm losing light, I usually just pull the TC off altogether, rather than switching to the 1.4x TC. Haven't had a situation where the conditions dictated that I could use f/4 for a while, so I don't have any direct comparisons. I guess I could go out and do some test shots where I shoot the same thing w/ all three configurations.

Given my budget, and the flexibility that it gives me, this setup is working out for me. Will I eventually get a 100-400? Not sure. Would like to, but I'm not sure. It would make it a much easier choice if it was a 100-400 f/4.

My 70-200 f/2.8L IS + Canon 2x TC Mk II works fine, but when i really want some crisp sharp images it required to be stopped down at f/8. Well kinda like the 70-200 @ 200 f/2.8, much better at f/4 or f/5.6 :P
I guess the 70-200 f/2.8L IS II shine wide open even with extenders.

Chris_R wrote in post #10248679
I guess the 70-200 f/2.8L IS II shine wide open even with extenders.

This is what I have been searching for! I have a 7D and am planning on getting a 70-200 f2.8 IS II in the near future. I was considering adding in the 2x II extender but wasnt sure of the IQ hit that would result in it. Does this lens really offer a significant improvement over the Mark I when using it with a 2x extender? Does anyone have first hand experience with the Mark II and the 2x, and if possible could you post images with it in use?

There is this topic that compare the 70-200 f/2.8L IS II to the 100-400, but not the 70-200 f/2.8L IS

At the risk of repeating what may have already been stated:

picard wrote in post #10244859
what is the result F stop with the 2x extender ?

to find the resultant f/stop with the converter, multiply the native f/stop of the lens by the extender's multiplication factor. the algebraic proof is trivial, and is left as an excessive for the reader . examples:

f/2.8 times 2 = f/5.6
f/2.8 times 1.4 = f/4
f/5.6 times 1.4 = f/8

yes

Well, just to be precise, mounting 400mm lens on a 1.6 crop body doesn't actually change the focal length to 640mm. What you mean here is that the 400mm lens on a 1.6x crop body yields the same field of view as a 640mm lens would on a full frame body. I'm sure there's an eloquent FAQ on this subject