Tom Reichner wrote in post #18553506
What were you expecting?
It is a pretty well known fact that tele-extenders generally work best when used with the really huge, super-expensive primes like the 400 f2.8, 600mm f4, and 800mm f5.6.
You are making a huge compromise when you take a lens like the 100-400 v1 zoom, which is already not so great optically, and then you magnify all of those optical imperfections by putting a 2x extender on it. .
I don't think that Canon designs this lens to be manually focused, because it is an autofocus lens that is usually used for sports and wildlife, two genres that are largely dependent on autofocus.
Because you are using a 2x extender, you are not able to use autofocus. .
So it is rather apparent that Canon didn't really design the 100-400mm to be used with a 2x extender. .
The extenders - especially the 2x - are really designed to be paired with the very long, fast supertelephotos.
You are trying to use your gear in a manner that is different than that which it was designed for. .
They are not going to design their 100-400mm zoom to have fine-tuned manual focus so that use with a 2x is optimized, because they don't design the lens to be used with a 2x extender in the first place. .
They think that people who are very serious about shooting at 800mm are going to buy a legitimate 800mm setup. .
The same thing with macro - they do not design the 100-400mm zoom to have focusing that is optimized for macro use with extension tubes, because they think that serious macro shooters will buy a proper macro lens for their macro photography needs. ..
Now you're talkin' my language!
I don't think you'll be at all happy with any wildlife photos taken with the 100-400mm v1 and the 2x extender. .
It's a focusing nightmare. .
And it is also a really poor optical combination, compared to other ways of getting to the 800mm range (or close to it).
I do A LOT of wildlife photography, and my most useful lens is my 100-400mm zoom. .
But I don't use it with extenders. Just the 100mm to 400mm range is plenty of reach for many wildlife scenarios. .
I take more quality wildlife photos with my 100-400mm zoom than I do with my longer lenses, which include a 400mm f2.8 and a Sigma 300-800mm f5.6 ..
That's right - more times than not, there is no need for more than 400mm.
So my point is that I think you can use your 100-400mm for wildlife the way it is, without putting any extender on it, and that you will do very well with it and find that you are actually able to fill the frame with the animals and not have to crop. .
Of course, there will be times when 400mm is not enough ...... but if I were in your shoes I would be content to just let those situations slide away and not bother shooting them until you can get a longer lens. .
What good is a photo if it is not going to be nice and clear and sharply detailed? .
You can't make caviar out of feces (or whatever the saying is).
Overall, I think that what I've said here is a big positive for you, because it means that you can use your lens the way it is intended to be used (without an extender), and still get great results. .