ronz wrote:
Sorry I shoot Canon, 5d iv & 7d ll. So I have full and crop
For sports/action I've been using Canon 100-400L IS "II" a lot the past year and a half... It would do very well for wildlife too, as a very versatile zoom lens with superb image quality throughout and on a 7DII it's got lots of "reach". (It's said to work well with 1.4X teleconverter, too... on cameras like yours and mine that can autofocus an f/8 combo, but I haven't really tested it.) Here are a couple examples with the 100-400 II (out of many thousands)...
For above it was on a tripod with a gimbal mount... but those were from a four day event where I was shooting twelve hours a day or more. As a over 3 lb. for the lens, combined with a 7DII with battery grip that's probably 2+ lb.... they are certainly hand-holdable for quite a while, just get pretty tiring during those "endurance" sessions.
I don't do a lot of it, but for BIF I prefer 300mm f/4 IS or 70-200mm f/4 IS or 70-200mm f/2.8 IS, all of which are both slightly smaller and a little lighter than the 100-400mm for hand holding over a period time, as well as for their larger apertures, slightly faster autofocus and slightly better focus tracking... To be fair, they're all quite fast and seldom miss. But f/4 is a wee bit better than f/5.6, and an f/2.8 lens is a wee bit faster than f/4 (you probably know... f/2.8 or larger allows many Canon cameras' AF systems to work their best). The 100-400 is f/4.5-5.6 (f/5 up to about 300mm, then f/5.6 out to 400mm).
For BIF in particular, some people really like the original 100-400L IS with it's push/pull zoom. It's just a personal preference, but I'm not a fan of that type of zoom and prefer the 2-ring design of the 100-400 II.
300mm f/4 on 5D Mark II:
And 300mm f/4 on 7D:
The EF 400mm f/5.6 is another popular lens among birders... but it lacks IS. I don't use it and prefer the EF 300/4 because I can get very nearly as good image quality with it combined with an EF 1.4X II teleconverter, for a 420mm f/5.6 combo
with IS. This also gives me two focal lengths to work with, instead of just one. Below is the 300mm + 1.4X combo on 5D Mark II:
I don't have any examples of it with teleconverter, but EF 135mm f/2L is another great lens on a crop camera alone or with a 1.4X where the combo makes for a 189mm f/2.8. This was shot with 135mm alone:
Finally, I'm pretty sure the 300mm f4L and the 100-400mm II are the closest focusing of the Canon telephotos longer than 200mm. Where many of the others can do 1:5 or 1:6 magnification at best (the 400mm f/5.6L can only do 1:8, 0.12X at over 11 feet). In comparison, without any added extension tubes or close-up diopters the 300mm can focus within 5 feet for about 1:4 (0.24X) magnification and the 100-400mm can do almost 1:3 (0.31X, just over 3 feet).
This was shot with the 300mm f/4 near it's closes focus distance: