I'll start off with what I have and scenarios:
I moved from 7DMKII to 5DMKIV and am happy with the move, the quality really is something else but that left me in lens dilemma.
Canon 5DMKIV
Canon 24-105 f4L II
Canon 35 1.4L II
Canon 16-35 F4 (just purchased)
Canon 70-300L
Canon 100 F2.8 L
For my portraits that we shoot, I used the 35 A LOT on my crop sensor and it was nearly perfect for what I need in group shots or close ups. But now that I'm on FF it's only good for limited scenarios. I currently use the 100mm Macro for portraits and am considering the 85 1.2L as I rented it and really liked it. I'm also waiting for a newer Canon 50 1.2 to come out as the current is just too soft and slow.
With that said, I recently purchased the Canon 16-35 F4 because I wanted to replace my Canon 10-22 EFS lens that does not fit my 5D. It just came in, it's a great lens, leaps and bounds better than the 10-22, especially in the corners. I woke up this morning and started to think about lenses; I feel that I may have a little bit of an overlap and potential waste in money right now. I have the 16-35 F4 and the 35 F1.4 lens, would I be better off to return the 16-35F4 and sell the 35 1.4 and buy the 16-35 F2.8 III? I could use it for my UWA Landscape needs and zoom in to 35 f2.8 for certain portrait needs.
I'm going to re-read Bryan's review on the lens but are the corners on this lens closer to the 10-22 or 16-35 F4? I also noticed that the 16-35 F2.8 has a filter size of 82mm vs 77mm on the F4 version. That's a bummer as I have a really nice B+W CPL that I use on the 24-105 and was planning on using for the 16-35 lens.
Note, the 16-35 would not be used for portraits, but for Landscapes. There's been a few times where I've used 35mm for portraits and so I would use this lens for that as well if warranted.
Thoughts? I hope this all makes sense, I'm still weaning myself off of cold medicine.