First a bit of context. I currently shoot exclusively birds, first with a 7D II and 100-400 II, but I've also added a 500 f4 II and recently a new 5D IV. I've never really taken a landscape photo, but in my birding travels, I'm often out early morning or late evening, and get to see some beautiful glimpses of nature. In those times, I say to myself "wouldn't it be nice to have a lens for landscapes" (especially recently with great fall colours). Also, my cottage is at a very dark site, and doing some astrophotography (Milky Way, time lapse, etc) would be great.
I have a chance to pick up a used 17-40 L f4. Would this be a suitable choice? I'm only going to be using this infrequently, so I don't need the best available, but I would like something of decent quality. I always have a tripod around for my 500 f4, so stopping down for more quality or lack of IS shouldn't be a problem.
Appreciate any advice.