The "old" Canon 100-400 was, and is, an excellent lens. Check out this review:
http://www.kenrockwell.com/canon/lenses/100-400mm.htmI recommend buying one used from
www.keh.com or
www.bhphotovideo.com Both are reputable dealers who warranty their used equipment.
https://www.keh.com/shop/canon-ef-100-400mm-f-4-5-5-6l-is-usm-telephoto-zoom-lens.htmlThey have one for $729 with the hood, case and caps in "bargain" condition. Hard to beat that deal. KEH "bargain" grade equipment is generally quite excellent; it is the grade I usually buy from them because the glass and function will be perfect, and the only real wear will be cosmetic.
As far as a camera goes, I would buy just the body and the 100-400 lens. Use your iPhone for everything else. Anymore the iPhone camera is so good, and so fast to use, that I use it for everything that doesn't require a specialized lens like a super wide angle, a super fast lens, or a telephoto lens. Save your money (or put the money into a better camera body) and skip the camera/lens kits--if what you want and need is a telephoto, buy the 100-400, put a body on it, and go shoot until the camera pukes, then buy another camera and shoot it until it pukes. Your 100-400 will likely outlast any cameras you buy. Good lenses are investments. Camera bodies are consumables.
