It works fine if you just focus on specific parts of the galactic core, which is available this time of year. If you're just shooting the core where all the interesting stuff is, you're good. If you're trying to get the whole shebang, you will need to do a pano. I don't recommend you try to just do panos all night unless you're already experienced with it. Just focus on simple good exposures of the core and enjoy learning to process it and getting something out of it.
In your place, if shooting mikly way, I'd opt to try your 16-35 over just the 35A. F1.4 sounds great, but you don't need that. You'd be fine shooting at 20mm F4 for 30 seconds at ISO 6400, give or take. I'm not sure how the coma control is on that lens, but I'd go that route before worrying about a 35mm just because it has F1.4.
Then again, a simple tracker would relieve you of many problems and is way cheaper than a lens.
++++++++
Example:
Cheap Rebel (650D) (remember APS-C for effective focal length here)
35mm F2 IS & 85mm F1.8
Cheap tracker (iOptron Skytracker)
20140501_053133 by
Martin Wise, on Flickr
I can get:
(35mm) 4 minutes at ISO 400 wide open at F2, this is a single exposure:
IMAGE LINK: https://flic.kr/p/kRyn6x DPP_0794 by
Martin Wise, on Flickr
(85mm) 2 minutes at ISO at ISO 400 at F2, this is a single exposure of same region:
IMAGE LINK: https://flic.kr/p/kPpDSi DPP_0782 by
Martin Wise, on Flickr
These days, I'd suggest a SkyWatcher Star Adventurer ($300). Use any focal length of 200mm or less and it's still very easy to get 2~4 minute exposures. Nothing wrong with 35mm on any sensor size. It's all about what you're wanting to actually see.
Very best,
