Good one, oldtimermetoo (#8). I had intended to mention the Zeiss Softars for the Hasselblad, but forgot. When I used a 'blad I had the three Softars, and used them now and then, for exteriors when a certain amount of "fuzz" was called for. I also have them for the Rolleiflex. They are life savers and do wonders if you shoot portraits of sitters "of a certain age".
during my 20+ year career in interior design, THE camera I most wanted to own was the Hasselblad SWC, but alas! it was an unaffordable luxury and none came my way at a price I could afford. Then, not long after I retired in 2012, out of the blue at a camera club outing I was offered a 1970 SWC in VG+ user condition, the seller initially wanted A$1,800 for it but I told him I couldn't justify the price and made a lower offer which he turned down. Two months later he called and left a recorded message on my home phone, offering me the SWC for my offer of A$1,000. I was overseas and only got the message when we came home, by which time he was overseas. Years later we met again and he told me he sold it in New Mexico - for US$700! That really hurt. I have bad dreams about all this even now.
Sad stories aside, over the years I had many discussions with older architects who, as I did, shot all their own images, largely because we are more idealists than business types and for most of us architecture wasn't the best paying profession around. In the 1990s a (now deceased) leading Australian architectural photographer summed it up for me in an apt comment. "It's all about f/8, shoot on sunny days, and watch the verticals. Let the horizontals take care of themselves."
True words indeed. When shooting with a 28mm (in '35) or MF equivalent, even with a tripod, a certain degree of "sag" in many of the straight lines is visible, and as I've found, if the vertical lines are properly, well, vertical, my clients mostly ignored a slight amount of lean in the horizontals. When out shooting, a small spirit level can be your best friend. I carried a small carpenter's level in my camera kit for many years and put it on top of the Rollei WLF (waist level finder) before every new shoot. This worked well for me. My 35mm cameras all have a small spirit level, these are available on Ebay at little cost and they do the job well. Of course a solid tripod is a must.
As well, unless you specifically want this effect, I suggest you should avoid the "falling over backwards" effect so often seen when using the wider angle lenses. This is regarded by the profession as amateur work and architects (and clients) greatly dislike it.
If one works with care and not in a rush and uses the right tools (even inexpensive ones) to shoot architecture, usually the results will be OK (= publishable) and everyone will tend to like them.