> The 23mm f2 looks cool but is it too bulky for a pocket? Saw this earlier but just getting back to ya. Honestly, I'm super happy with the Fujifilm XF 23mm f/2 R WR. It fits fine in a jacket pocket, even if it isnt a pancake. The AF is miles better than the 27mm... super quiet. Another solid pick is the Viltrox 23mm f/1.4 AF. Its slightly larger but that f1.4 is a lifesaver for night shots in Shinjuku. Both work well!

Ive handled most X-mount glass over the years and for Tokyo, you need to stay small.

• TTArtisan 27mm f/2.8 AF: A 93g budget pick. Fast AF and an aperture ring for cheap.
• Fujifilm Fujinon XF 18mm f/2 R: The 28mm equivalent field of view is ideal for tight alleys. It is only 40mm long. Stick to these two, the 23mm f2 is way too chunky for pockets.

Honestly, I've been using the Fujifilm Fujinon XF 27mm f/2.8 R WR on my X-E4 for over a year now and I'm very satisfied with how it performs. I was actually in your shoes before a trip to Osaka last fall, worrying about the autofocus being slow or noisy like people say online. In reality, it works well enough that I never missed a shot. The noise is basically a non-issue outdoors in a city like Tokyo where there is constant ambient sound anyway. It makes the camera feel like a tiny point-and-shoot, which is exactly why I bought the E4 in the first place. I did try the Fujifilm Fujinon XF 23mm f/2 R WR for a bit, but it sticks out just enough to make it awkward in a jacket pocket. Its a great lens, no complaints on the glass quality, but the size kinda ruined the stealth factor for me. With the pancake lens, I could walk around all day without a strap and just slide it away when I went into a ramen shop or a crowded train. If you want reliability and that true compact experience, the 27mm is the safe bet. Quick tip: Grab a spare Fujifilm NP-W126S Li-Ion Battery because that small body means youll be swapping them often if you're out from morning till night.

To add to the point above: you really need to be careful with the mechanical construction of these ultra-compact designs. Over the years, I've seen too many people grab a lens with an external focusing barrel only to have it fail after a few days in a busy environment. If that barrel gets even a tiny bit of grit or a minor bump while it's extended, the motor will strain and eventually throw a lens control error. It's a common failure point that folks ignore just for the sake of saving a few millimeters in size. Also, check for decentering before you leave. I've tried many copies of compact primes where the internal elements weren't perfectly aligned from the factory. You wont notice it on the back of the camera, but once you get those Tokyo street shots home, you'll see one side of your frame is mushy. Since you're on a tight deadline, do a proper test on a flat wall the second the box arrives. Reliability is everything... you dont want to be hunting for a camera shop in Ginza because your AF motor decided to quit or hunt endlessly in low light. Check the firmware too, because older lens code can really tank the battery life on an X-E4 if the processor is constantly fighting to communicate with the lens.