If youre going to Tokyo and want to stick to just one lens, you basically have two real choices for that Z5. In my experience, the Nikon NIKKOR Z 24-200mm f/4-6.3 VR is the absolute king of travel lenses. I've taken it on a few trips and it's honestly incredible how much you can do with it. Since you dont want to be swapping glass while walking through Shinjuku or crowded temples, having that 24mm wide angle for streets and 200mm zoom for details is a lifesaver. It fits your budget perfectly too. Another solid pick if you care more about sharpness and a constant aperture is the Nikon NIKKOR Z 24-120mm f/4 S. I've tried many zooms over the years and this one is arguably the best all-rounder Nikon has ever made. It is a bit pricier and might push that 800 dollar limit depending on where you shop or if you find a sale, but the S line quality is really noticeable. The colors and contrast are just a step up. Personally tho, for a first trip with a Z5, go with the 24-200mm. The vibration reduction is great for handheld shots when the sun starts going down in the city, and it is just so versatile. You wont feel limited at all. Just make sure to grab an extra battery because you're gonna be taking a ton of photos... Tokyo is a lot of fun for photography. Let me know if you need help with anything else before you head out.