Thanks for the detailed reply. Thanks for pointing me back to your earlier review, but your recommendations there are mainly for the 21mm range, and I already have an OM 21/3.5 that’s okay.
Given the information I wrote, I think you’re right, the FE16-35 has the best quality and as for my weight concerns, its ability to remove 3 of my primes (15mm, 21mm and 35mm) means it will actually lighten my load!
Thinking it through again, what I forgot to mention (even to myself) is that one of my objectives is to avoid being married to one brand or system. I did that once with Panasonic and paid a heavy price to shift to Sony. After that I decided to buy old lenses that are broadly compatible with any mirrorless system. Whilst I currently adore what Sony are doing, I want to be able to easily switch to a different FF mirrorless brand (even Nikon!), if doing so makes sense.
Therefore, committing £1k to Sony gives me the shakes!
Secondly, I’m relatively new to photography as a serious hobby (4 years) and I find that using primes really improves my photography…it’s nothing to do with IQ, but something else.
Thirdly, and this may seem trivial, but I find it very satisfying being able to tell what focal length I need for a certain shot, and I attribute this to my exclusive use of primes. I’ve no idea if it helps my photography, but I like the fact it’s a skill I’m getting good at that I never was able to develop using zooms.
So taking these 3 new points into consideration leads me back to the Voigtlander. Regarding the filters problem, Ken Rockwell uses screw-in ND grads…he says they can fit any angle and he doesn’t find it crucial to get the vertical placement correct. I think this compromise might be acceptable.
I’m not in a desperate hurry to buy, so I will think it through a bit more. It may be worth my while buying a secondhand circular ND grad to test out.
Perhaps after a bit more thought I will build up the courage to commit to Sony…we’ll see 🙂 I’ll let you know the outcome.