Thank you.  This review was very helpful to me.  I actually just purchased the 100-400 and your review helped me feel confident with the choice I made.

Great comparison review, Scott. On a recent trip to Canada this past autumn, I took my 600G ED VR, 500PF, and the 100-400. We were mostly photographing mammals; Elk, Bighorn, Grizzly's, Black Bear, and we did encounter a few Great Gray Owls (I know how much you love owls), and I found myself all most exclusively using the 100-400, with few exceptions. It's a fantastic lens and has earned a spot in my kitbag.

Appreciate the info!  I've got the 100-400, and love the versatility for wildlife, sports, air shows, you name it.

Great review!! I like the concept of picking a focal length to do the comparison. I also liked your “who is this lens for” summary at the end.
Would be neat to do another review when the mythical 200-600 arrives, and also a @600mm (560mm) comparison between the four lenses (400 2.8, 4.5, 100-400 + TC; 200-600).

Great comparison.  I purchased the 100-400 a little while ago and love it. Completely agree with you on how sharpe it is.  Takes the 1.4 TC really well too.

Great review. Owning a 300 2.8 VR, 500 F4 FL, and 400 4.5 (and having owned the 80-400 and 180-600), I must say that the weight, size, and image quality of the 400 4.5 are incredible, and for most situations it is the best wildlife lens there is. (Ps. I used to own a  300 F4 PF, and it is also amazing, and at least my copy of 1.4 TC and lens were excellent at 420 5.6.)

Awesome review Scott!  Best comparison I’ve seen so far.  Appreciate it!

Great review!  I especially like the fact that you stayed within the Nikon lineup. Many similar reviewers test across brands which, to me, is irrelevant since I’m not going to junk my Nikon gear and switch to Canon/Sony for a single lens. I just bought a 100-400 and have been wondering if I should keep my beloved F mount 70-200. You just gave me the answer: indoor events with the FTZ adapter and the 2.8 light gathering.

Very helpful comparison. I recently got the 100-400 especially for it's combination of versatility and sharpness.

So impressed by the 100-400 that I sold my 500PF and bought the TC1.4… that I can also use with my 70-200 (light gear)…

Nice work Scott! A complex subject whittled down to comparisons most understand. Thanks for that extra mile to the finish. Well Done!

I guess it should have been at least the third time I am watching this video by pausing, checking and continuing in order not to miss any information that I couldn't find any other channels and the this time I am watching it after buying 400mm f4,5 and I realised that I missed iso comparison at the widest open aperture part somehow... :O I think this is a very valuable comparison which degrades into numbers of real world scenarios... So I would like to share my appreciation for such a good comparative video you made... I do know by watching them too that this is not the only video of yours for such side by side impressions as I am also watching many of them as a loyal follower of your channel but this one is special for me.

So please keep up your good work and big thank you for all of your efforts... 👏

I came across this video again, after previously watching & liking it quite a while ago, and I decided to watch it again. Great comparison video Scott! Very detailed & useful information!

Outstanding work sir! Fantastic! I happen to know that yes, this type of video is a crazy amount of work! Thank you for your service to the photography community!

Agree with all the comments below about this being the best comparison I've seen on youtube.  The consistency of your shots on the tennis balls really helped make the comparison of lens sharpness each easier.  I do mostly indoor sports - volleyball - so the 70-200 is my current lens but I was wondering how it stacked up with the other lenses for bird phototgraphy with the 2x teleconverter.  This completely answered that question.  Also helped me realize it could be used for psuedo-macro in back yard or out in nature with an extension tube so going to give that a shot.

The 180-600mm f/5.6-6.3 does 400 at 5.6. Could be an option.

Perfect timing as I am in the market for a 400mm lens from Nikon. I also love the criteria you used, and the order of importance. Brilliant comparison!!!

Excellent and one off review! i have the 100-400 and it is a very versetile lens, for what it can do i think it is a must have for all serious photographers wherever genre they're in.

Scott, I just loved this video. The lens comparison you made keeping most of the wildlife photographers who may not have enough budget to afford beast like 400f2.8. And you rightly said, the sharpness difference is not much noticeable between 400 f4.5 and 2.8. A stop and half of light, we may increase iso accordingly. And keeping noise reduction softwares like DXO pure raw, Topaz denoise and Adobe Denoise in mind, spending $13k dollars is not an option except for pros. But enthusiastic photographers like me, it's a 400f4.5 go to lens.

Nice review/comparison of the 4 lenses! Well done.

Can't wait to get my hands on the 400 2.8 for sure.