Right off the bat I just want to say that there is no right or wrong answer to this question. In truth, the lens you choose is probably going to reflect your confidence levels as a photographer. If you like mixing it up on the street then a 28mm is probably perfect as it gets personal at that focal distance. If you are a little shy or worried about photographing strangers then a longer prime or even a short zoom is probably going to favour your style of photography. The essence of this article then is that, there is no perfect lens for the job, it’s all about you and your confidence levels as a photographer!
All this being said, it’s hard to imagine anyone doing street with a long zoom. Candid / street photography requires you as much as possible to blend into a crowd and nothing shouts photographer like a DSLR armed with a long zoom. Equally, a fisheye or an ultrawide lens is pretty much useless in my opinion unless you like standing toe to toe with your subject. With that lens you are going to see more that the whites of their eyes and that means getting very personal. Great for urban landscape photography for sure, but candid people biased photography, in my opinion, leave it in the bag or at home. Now while some photographers also spout long and hard about the benefits of vintage glass, which is often manual focus of course, forget it. It’s not 1961 when you had no choice, it’s 2021 when you certainly do. Rely on a manual focus lens / camera combo and I guarantee you that you’ll miss that pulitzer price winning shot when the opportunity arises. In fact I’ll go as far as to say that you’ll miss a lot of really good shots. In street, great images don’t come along everyday so when they do, you need to be nimble and nimble means more often than not, nailing it on auto.
For me, the sweet spot for street and candid photography is going to fall somewhere between 24mm – 75mm in full frame terms although my favourite squeeze for candid photography today is the pocket sized Canon G7X, purely because when I started to get really interested in street and candid photography, that is what I bought. I use it a lot for street because it’s small and unobtrusive and easily fits in a trouser pocket so is highly portable. The 8.8 to 32mm lens combined with the 1″ sensor seems to capture great shots even in low light. In full frame terms that’s 24mm to 96mm so pretty handy for street. In truth though I’d be equally happy with any good quality 1″ sensor compact nowadays, such as Sony or Lumix. Another good option of course is the Fujifilm x100V (or an earlier variant) and the x-Pro series ie version 1 through 3. All great cameras for street and candid photography.
Another favourite of mine is my Panasonic Lumix GX80 which has an M43 sensor. Again it’s small, descrete and very capable. Armed with the Lumix 12-60mm f2.8 (or even just the f3.5 if cash is tight) this is a great street combo because again, it’s small and compact. In fact it might equally be as good with the kit lens, the diminutive 12-32mm. What I certainly wouldn’t take out with me is my Nikon D600, even with a tiny pancake lens. Way too big for serious street work. And although I have used my Fuji x-T1 a lot for street photography, especially with the 18-55mm f2.8-4 and the Viltrox 23mm, I still think that this size is too big for serious street. This is because with street photography you really just want to blend into the background, not make a statement along the lines of “hey, look at me, I’m a photographer and I am photographing you!”.
Now I am a member of a couple of Fuji facebook groups and the buzz on these groups is about SOOC photography ie straight out of camera shooting. Like many, I do like the jpegs that Fuji cameras can create, especially with a filmic simulation applied in camera but I maintain that for good street photography it pays to blend in and you’ll do that best with a small, innocuous camera like the Canon G7X or something similar. Because I am as happy playing with RAW as I am with JPEG’s, I don’t worry too much about SOOC although as I mentioned, with the right light, Fuji cameras can produce stunning yester-year film quality results. As mentioned above, for the serious Fuji street photographer I would suggest that you look at the X100V or perhaps the X-Pro3 if you want lens interchangeability. These two cameras for me, along with many modern compacts are about as perfect as it gets for street and both sit alongside my Lumix GX80 and Canon G7X for this very reason.