I haven't used the lens you have, so I am not sure how good it is. I have used the 70-300 II USM lens with my Sl2 and have found it to be an excellent lens. I have been particularly impressed at my ability to get good shots of whales from quite a distance away. I have also used it for birds (though maybe closer than you will be) and been very happy with it. I use a 100-400 II on my ff Canon cameras, sometimes with the 1.4 teleconverter. It is a great lens, but if I am moving quickly and my subject is moving quickly, I like the lightweight of the 70-300 lens. I really don't know the Tamron lens you are looking at. It could be good and would give you the advantage of single lens if the quality is good enough for you.

I have an sl2 that has a similar sensor to the 80D that I use for bird and wildlife photography from my kayak and other boats. I have the 70-300 ii IS nano lens that basically lives attached to the camera. The combination is incredible. I have been really super pleased with the results even when my subject is some distance away. You are thinking of the 70-200 f4, it would be an even better lens than the 70-300 except for the lack of reach. I think you would be really happy with it for longer shots, and it would be an upgrade as well as a useful addition to round out what you already have.

This camera is okay, but I think you might be happier with a used 6D, which might be able to get at almost the same price. It is more limited in terms of autofocus, but has many other newer features. It is especially good in low light.

I bought a refurbished Canon sl2 and 70-300 usm II nano lens to use in boats and other places where I don't want to risk one of my better cameras. I agree with those who say the tough cameras won't cut it--they are too limited in features and in zoom capabilities. My solution has worked. A whale spouted on my first camera (the flash doesn't pop up any more, but still flashes correctly if manually raised--not that I have ever used the flash except to see if still worked). My friend is still using it and getting beautiful photos. I flipped my kayak and had the second camera in a non-drybag backpack, more of a purse really. The camera survived just fine--no damage, though I had to replace the lens. Drybags are great for protecting camears and the day I flipped the kayak was the only day I forgot to put the camera in--some kind of law there. I try to look for sales on the refurbished gear, so I don't have a big investment, but except for the lens, all has been fine. Before I adopted this solution, I used a variety of tough cameras and a very old (9 years) Panasonic point and shoot--which would stop working when it got too wet, but wasn't bad when dry. It still works by the way, though it has spent some time in bags of rice to dry it out.

I was honestly amazed at how well even the bottom of the line Canon camera survived getting dunked without taking water in. I think the Canon guys who looked at were pretty amazed too. Not that I would recommend taking a camera out without a drybag. As for dust, I have had plenty of that too with my good cameras. Maybe a rainsleeve????

great shots!!!

Has several people here have noted, if you notice spots in the sky (or even clear water), it is very possible that the spots are on the sensor. I have had more problems with sensor dust on my two sony cameras (one was an a7iii; I am now using an a7riii) than I have had since I had a Nikon d600. You need to be very careful changing lenses, almost always use a blower, and see if the not very functional Sony mechanical cleaner works.

And maybe you shouldn't make responses like this without reading the thread. If you did, you might realize why weight matters to some photographers who are looking for solutions that will enable them to continue to enjoy something they have always enjoyed doing! I wish you many more years of good health and safety so you can continue to carry your Mamiya around without effort!!! (I do mean the last wish seriously)

You might try Canon refurbished, especially if they have deals going on (can happen at odd times--one of best deals I got was a St Pats day sale last year). Everything I have bought from them has been like new and comes with a one year warranty.

The only dust spot I ever had on any of my Canon cameras was after using the 28-300 in Death Valley where the winds were pretty bad so a lot of dust in the air. I never had any issues with the 100-400 original I had, but I find the II to be a significant upgrade. The dust was easy enough to clean out with a rocket blower, so not a big thing really.

I don't have the a7ii so I can't really help you there. I did get the a7iii and the kit lens you are looking at. It is significantly lighter than my Canon full frame setups. I got a good deal on the a7riii and got it because I wasn't really satisfied with the resolution on the a7iii, but that is me. The kit lens is not bad (though it is a long way from being among Sony's best lenses. I got the 24-240 which is of comparable quality for more range. Both are very light and good for a full frame light setup, but you may want better quality. I think the a7iii has some improvements over the a7ii, but the a7ii is probably a good camera.

That is my personal experience or as close as I can come to what you are looking at. I don't really know what you are really looking for. For serious shooting, I prefer my Canon cameras but the Sony is a good choice for hiking, etc. where I really need something lighter. Unfortunately, the only way to get light is either with primes (some of which are terrific) or Sony's less expensive lenses, lighter weight lenses.

You should be good with what you are looking at.

To the OP, I spent some time with this computer as one demonstrated its ability to do PS and LR--it looked really good and I was already to buy one, but then Costco had a Dell 15, the xps 9560 which was cheaper and pretty much would do what I want. The one I bought (which probably isn't as good as the one you are looking at) does very well with my 5dsr files (which are pretty big) and can even work with Sony a7riii uncompressed raw files, which can be huge. It does slow down a bit with the latter, but for a pc that I could plug right in and use, I am very happy with it.

It goes through batteries faster than my 6d did (but still does pretty well, especially compared to my Sony cameras). I carry an extra battery, but rarely need it unless I really am shooting nonstop all day or doing star trails at night (when I always put in a fresh battery before I start). I am not sure what causes it.

Especially if you are shooting raw, turn off the in camera lens adjustments (I think they are in like the second and third menu). When I got my camera, the default was to have them on, and it really slowed it down. Once I disabled them, the buffer cleared much faster.

Thanks to all who have responded here! This is an interesting and helpful discussion!