If I already own a NikonP900 "superzoom" camera, would it be worth the expense to get a very long lens for my Canon 80D, or just use the Nikon for those rare situations where I might want to take an extreme focal length picture? The longer lens I'm considering is the Tamron 150-600 which would give me a 960mm equivalent, and almost as much as the Nikon's 2000mm long end if I use a 2x teleconverter. However I'm not sure if they make a 2x teleconverter that will work with EF-S lenses, and that has to factor into the price as well.

My thinking is my best bet would be to get the Tamron 18-400 lens for the Canon to give a very good "all purpose" zoom range with a good telephoto long end (1.6x400=640mm equivalent) and just use the Nikon for anything longer than 400mm, unless there is such a drastic improvement with image quality using the Tamron 150-600 with a 2x teleconverter as to make it a better choice.

I have the Canon EF-S 55-250 zoom but I do often find I need more reach for wildlife. Any guesses as to the Tamron 18-400 image quality versus this budget Canon lens?

What are you shooting? Is it moving? What is the light like? I would think an actual long lens would outperform a bridge camera, but they have come a long way over the last few years.

So the landscapes I like to shoot are obviously pretty static. But to get close to things like antelope, deer, chipmunks and birds I want something better (and longer) than the 20 year old EF 75-300 I bought back when I had a 35mm film camera.  The chipmunks and birds obviously move around quite a bit.

The Tamron 150-600 G2 gets great reviews. But it isn't going to get me as close as the Nikon P900. but then what's the point of getting that close if the image quality isn't comparable. I guess it's all a balance of compromises. I'm never going to sell any of my pictures, but it's not like the Tamron is an "L" lens anyway. Decisions...

You're going to want something very wide and very long.

My wide vote is the Tokina 11-20 or 11-16.  Though I must say the 3mm lens on the GoPro Hero 6 does have a place in my bag.

Tokina:
Approaching Cell Pano 2 20180531 by FredMan, on Flickr

GoPro:
BI1012 Stand 0015 by FredMan, on Flickr

On the long end, the Tamron 150-600 is hard to beat.

ETA:  With a crop-sensor camera, that 600mm is really 900mm for a full frame/35mm equivalent.

Osprey Piling by FredMan, on Flickr

Tripod Family by FredMan, on Flickr

Big Buck by FredMan, on Flickr

Thanks for posting these great pics! I have something for the wide end already. I bought the travel and portrait lens pack which has the EF 50mm f1.8 STM and the EF-S 10-18mm f4.5-5.6 IS STM, which got decent reviews. It's not the fastest but for landscapes on a tripod I guess that's not so important.

I will probably try to get one of the Tamron 150-600 g2 lenses later this year.

A 2x teleconverter is going to reduce the light coming into the lens by 2 f-stops.
The Tamron 18-400mm f/6.3 becomes an f/13 lens, same for the 150-600mm, which makes auto-focus very difficult or impossible.

Since neither of those lenses are designed for use with teleconverters, if you can even get a TC to mount on them, the resulting images will be of poor quality.

So essentially, the 150-600 is going to be about the longest reasonably affordable telephoto zoom lens?  The P900 at max zoom is f6.5 so not too bad I guess.

my shooter nature/landscape pals at natty geo always carried a wide rig and a long rig

one lens to rule them all, seldom works to your editors satisfaction

I love my Tamron 150-600 G2 for wildlife.

Well, I ended up buying a lens yesterday, the Tamron 18-400. I have a 10-18 for the wide end, and the 400mm should get me close enough for the time being. Just messing around with it for a few shots today, it looks like it will be "good enough" for my hobbyist purposes and sharing pics online. It saves me changing from the kit lens to the EF-S 55-250 IS II, and gets me quite a bit more magnification.

Reviews that went in depth about sharpness suggest that if I keep the aperture around f8 to f11 it will stay pretty sharp. It's definitely not a low light lens and I will need to work out the best aperture/ISO compromise (softness vs. noise) for a given scene at the long end but it should be a great lens for the ability to just dial up 400mm in a hurry. (640 if you consider the crop factor.) Less lens changes means a cleaner sensor too.

Some negatives are that its not a Canon factory lens so there is no correction data available to upload onto the camera. And of course it's bigger and heavier than either the kit lens or the 55-250.

I run my 150-600 (G1) almost exclusively at f/9 or f/10.  It's noticeably soft at 5.6-6.3.  Corrections can be made in PS/LR, of course, but sharper on the sensor is always better than sharper in post.

The trade-off, of course is sometimes I have to boost ISO higher than I'd like, which introduces noise.  Noise is also correctable in post, and IMO post fixing of noise yields a better image than post fixing of sharpness.

And the more modern the sensor the better it is in controlling noise.  I see marked improvement (i.e. reduction) in noise at equivalent ISOs between the D200, D7100, and D500.

I'd like to try the G2 version of the Tamron just to see what I'm missing; maybe I'll try a rental some time.