TMcD Loc: Minneapolis, MN

You can use either the in body IS or the in lens IS, but they do not work in concert like the Oly 12-100 f/4.

I haven't done any in depth testing, but my experience has been that there is not much difference in effectiveness between the in lens and the in body IS. I expect one has an edge over the other, but they are pretty close.

pithydoug Loc: Catskill Mountains, NY

I have the 5DIII with the 100-400 L II with a 1.4 extender, that gets me to 640. With the 7d and just 100-400 gets you to 800 witch is quite good. For the caveat, it is not light but not sure if it would be too heavy for you . I don't know your limitations so maybe mono-pod would help. Another option for 7D would be the 70-200 but 400 may not be long enough. If you can get to camera store that has these lens in stock you can check out the weight, hands on.

BTW, the 100-400 with the extender on my 5DIII is bloody outstanding. With the extender you can't go wider that f/8 but did not find that a problem. With continuous shoot and AI+servo it tracks well although it will takes some practice especially if using spot focus.

Good luck

RickL Loc: Vail, Az

My teen daughter used a D7000 with a 55-300mm, I use a D810 with a 70-300mmm and a Sigma 170-500 mm. Both are crystal clear, my next lens would be a Tamron 150-600

davyboy Loc: Anoka Mn.

$2000 ouch!

Szalajj Loc: Salem, NH

But the results are worth every penny of that $2,000.

speters Loc: Grangeville/Idaho

I don't know which camera brand you're using, so this might not be of any consideration to you. The Canon 400/5.6 L is a very light (almost too light, as heavier lenses are easier for hand hold shooting). It might just fit your bill, it also focuses very quick and precise and the image quality is on a high level as well! This lens and camera can hang on your neck for days straight and you wouldn't even know its there!

imagemeister Loc: mid east Florida

Good advice here - except for the 300 2.8. - awesome yes, but it is MUCH heavier ! ( I have used one). Personally, I would recommend a 400 f4 DO II over the 300 2.8 in a high cost ( and heavier) prime.

I have settled on the 70-300 IS II nano and the 400 5.6 prime W/1.4X - both fast light and small.

Image below shot with the 70-300 @300 and f5.6 on 80D - for the nay-sayers ....

http://www.kenrockwell.com/canon/lenses/70-300mm-is-ii.htm

..

(Download)

davyboy Loc: Anoka Mn.

But I only have a $1000 now what how bout something cheaper yet high quality?

Szalajj Loc: Salem, NH

The only advise I can give you is to put away some more money and wait to make the purchase. The v.2 of this lens doesn't come up for sale as a used lens very often, but that's an option. Just make sure that you're buying it from a reputable dealer.

I would not waste my money on the v.1 of the 100-400.

imagemeister Loc: mid east Florida

Nothing wrong with the version I -IF- you get a good one - from a reputable dealer.

There are more AF options @f8 with the II version.

There are also more AF options @f8 with the 100-400 II than the 400 5.6.

Bob Boner

I highly recommend Canon's 400mm f/5.6 lens. It does not have IS but is lightweight and sharp. I used to use mine a lot, but now use the 100-400 lens. However the 100--400 is a lot heavier and I plan to go back to 5.6 lens before long.

JeffDavidson Loc: Originally Detroit Now Los Angeles

Nikon D5, D850 Nikon 200-500mm on tripod with gimbal head. i can't handhold either.

10MPlayer Loc: California

Got to agree. I don't own one but rented one for a week and it's an amazingly sharp lens even at 400mm. Can't speak to the doubler.

gessman Loc: Colorado

After shooting Canon full frame for a few years, having arrived at just over 80 with old sports shoulder injuries and beginning to feel my physical abilities starting to wane, I looked around for what I thought would be the most acceptable path of least resistance to answering the question you asked. I shoot mostly wildlife and some sports and having long ago opted in the late '90s for the EF400mm f/5.6 and EF1.4x II teleconverter as my best option for the combination of image quality (IQ), size, and price what I needed most was a body that would go with it and let me keep shooting handheld for the foreseeable future. What I first settled on was a Sony a6000 with an adapter because that cut the weight way down and gave me other features that I also wanted like more frames per second in burst mode plus a lot faster autofocus.

The only thing I felt missing then was stabilization on the lens and when Sony released the a6500 with the in-body stabilization and 4k video, I quickly made the switch to that. Sony has a menu feature they've entitled Clear Image Zoom (CIZ). It is a digital zoom that permits 2x magnification which doubles your focal range but it does so by sampling and filling in the resized image in a manner that doesn't cause noticeable loss of image quality so my 400 non-stabilized high quality Canon lens that is an effective 600 with the 1.5x crop factor of the a6500 sensor, times 1.4x from the TC, plus 2x from CIZ gives me an effective 1680mm of high quality reach with 11fps and stabilization for my developing tremors that I can handhold - the perfect answer to my question and perhaps yours. The only drawback is that I mostly need to resort to manual focus which isn't much of a bother since I've been at that for for a long time.

The Metabones adapter, I hear, is the best for retaining autofocus but I don't have it and haven't tried it so won't recommend it. Much of what I shoot ultimately requires me to resort to manual focus anyway so I'm ok with that. I do have a few Sony lens but when I get serious, I have used my entire compliment of EF lens with the Sony and am quite satisfied with the results. I do find that I'm using a tripod more for the long shots but that's to be expected. Good luck with your hunt.

imagemeister Loc: mid east Florida

The new Sigma 100-400 with the Sigma adapter to E-mount might be an option for you with the CIZ. ( no TC tho.) - but you would have decent AF !