Unfortunately, the Sony FE 50mm f/1.8 is a letdown because the focus is just too slow for moving subjects. I was disappointed with the noise on the Sigma 30mm f/1.4 DC DN Contemporary Sony E too, honestly. For street stuff in Chicago under 300, try the Viltrox 23mm f/1.4 AF Sony E-mount. Its much better for the price and wont hunt as much.

Re: "@Reply #1 - good point! Honestly, finding that..."

• I totally get that spec-sheet paralysis. I've been through it a dozen times, and honestly, the real world is always different than what the charts say. If you're hitting the streets in Chicago this summer, you're gonna want something that doesn't scream "I'm a photographer" and keeps your setup light. I've tried many budget setups over the years, and for a6400 users on a strict budget, there are a few sleepers that most people overlook because they aren't the big name Sigma or Sony G lenses.
• TTArtisan 27mm f/2.8 AF Sony E
• This thing is a tiny pancake lens. Its basically invisible on an a6400. The autofocus is surprisingly snappy for the price, and it gives you that classic street focal length that feels very natural for urban shots.
• Samyang AF 35mm f/2.8 FE Sony E
• Even though its technically a full-frame lens, it works perfectly on your a6400. Its incredibly light and way sharper than that cheap Sony 50mm everyone complains about. You can usually find these new for under 200 bucks if you catch a sale.
• Sony E 20mm f/2.8 Pancake
• If you want something wider for those tall Chicago buildings, look for this one used. Its not the sharpest in the corners, but for street shots, that character actually looks kinda cool and the size is unbeatable. My biggest tip is to check sites like MPB or KEH for used gear. You can often snag a Sony E 35mm f/1.8 OSS for right around 260 if you're patient. That lens has optical stabilization which is huge since the a6400 doesn't have it built into the body. Anyway, Chicago is an amazing place for photos... just keep your gear minimal so you can walk all day without a backache!

@Reply #1 - good point! Honestly, finding that sweet spot for street photography under 300 bucks is way harder than it looks on paper. When I first got my a6400, I spent weeks obsessing over technical specs and forum posts before my first big trip. I eventually realized that what works in a controlled setting doesnt always work when you are trying to capture a moving bike on a busy street corner. Not sure if this helps, but I have noticed a few things during my own journey with budget glass:

• AF motors vary wildly between third party brands. I think some of the older lenses use stepping motors that just cant keep up with the a6400 tracking system properly.
• Lens size really matters for street work. I tried a bulky lens once and felt way too conspicuous, which made it hard to get candid shots.
• f/1.8 is usually plenty for daytime street shots, so chasing f/1.4 might not be worth the extra weight or slower focus speed in every case. I remember someone telling me that certain brands have better firmware support than others, which directly affects how well the eye tracking works. IIRC, some cheaper primes struggle with hunting where the focus goes back and forth before locking. It is super frustrating when you miss the shot. Basically, it feels like a balancing act between build quality and electronic reliability. I am still trying to figure out which compromise I can live with for my own setup. If you can, maybe try to rent something for a weekend first just to see how it feels on the body.