Telephoto landscape lens: 70-200 F4 IS vs 100-400?

I have the 100-400 II and I like it. Have shot plenty at 100 and at 400. I've even shot some landscapes at 400.

I'm looking to focus more on landscapes, and as such aperture won't be quite as important. Plus, something like the 70-200 2.8 is just as big+heavy as the 100-400.

I owned a 70-200 previously and loved it. The F4IS is small and light, would be so ideal for travel. The wider 70 vs 100 could also be welcome, but of course I lose anything beyond 200. Then I was thinking of possibly carrying a 1.4 (should I even consider a 2x with this lens?) when I do want to go beyond 200. Even though I'd expect to be on a tripod with the lens a bunch, I'd certainly expect to shoot off tripod too and so IS would be welcome.

So... could sell my 100-400 and pick up the 70-200 instead...

Then there is also the 70-300 which I know virtually nothing about...?

BTW, would be paired with my 5D.

Very different lenses IMO.

70-200 F4 IS is a stunning lens for hiking/landscape work. Its light, can be handheld for hours and is tack sharp. I can't say enough about it. I have some landscape images shot with this lens in my gallery. Sometimes it stays on my camera for days. I shoot my family portraits as well as landscapes and some wildlife (crop body) with it (:. I'd also like to add that 70-100 is a very important focal length (at least for me) when it comes to both the landscape and portraits (FF body). This range sort of makes this lens so much more useful on a FF body than it is on a crop.

One thing this not is a wildlife/nature lens (especially on FF). Sure the extender helps but it is no replacement for 100-400.

70-300 II is touted as a reasonable value for price, however it doesn't hold a candle to F4 IS when it comes to sharpness across the frame as well as micro contrast.

There's also the 70-300L which from what I've heard is as good as the 100-400L mk2

seems like just a reason to spend money...you've got the focal lengths covered with good lenses...yeah it's a little bit smaller, and weighs about half as much, but gives you half the focal length too

if you don't use the lens at more than 200mm a lot then it would make sense

i'd say just buy a bigger lens than the 100-400mm, and then all of a sudden it's small and light

I have both the 70-300L and the 100-400ii. I say "have" but the 70-300L is on "loan" to our youngest son.

Anyway, the 70-300L is a very fine lens. It's very portable so it's a good travel lens and it's around f/5 at 200mm which would be fine for landscapes. It doesn't take telecoverters very well. I've heard the 70-200 f/4 takes a 1.4X telecoverter with good results though I have never tried it personally.

For your situation, I'd go with the 70-300. I haven't owned it, but it just seems like a fantastic do-it-all lens. The variable aperture is a small drawback, but for what you're shooting I don't feel as though it'll be a hindrance.

I cast another vote for the 70-300L. I like mine a lot, and it gives me great results, especially at the 300mm end. Of course, at 300mm, IQ for distant subjects may be limited by atmospheric interference. My shots of mountains about 20 miles away are not as sharp as the foreground several hundred yards away.

I have used the lens with my Kenko Teleplus III 1.4x on my 70D. (The lens is not supposed to take the Canon "extenders".) In daylight, my 70D seemed to autofocus fine, even with the rather hazy distant mountains. Results, however, may not be better than from cropped images shot without the teleconverter.