Man, I totally get that post-purchase panic when you realize the glass is gonna cost almost as much as the body. I was in a similar spot last year shooting a project in some really tight, dark basement venues. I actually ended up picking up the Viltrox 16mm f1.8 AF FE and it might be exactly what you need for those Seattle alleys. You might want to consider it because even though its a budget brand, the build quality is actually kind of insane for the price. I was surprised it had a little screen on it for the settings too... kinda fancy for a cheap lens. I would suggest being careful with the older Samyang lenses tho. I tried one of their early wide primes and the autofocus kept hunting right in the middle of a take, which basically ruined my footage. The Viltrox has been way more reliable on my FX3. That f1.8 is definitely gonna save you under those bridges. Even with the dual base ISO, having that extra light lets you keep the image clean so it doesnt look noisy or cheap. Just a heads up, the lens is a bit chunky compared to the Sony G series. Make sure to check if your gimbal can handle the weight if youre planning on using one. I almost dropped my whole rig once because I didnt balance it right after a quick lens swap in the field. Honestly, for around five hundred bucks, it feels like a hidden gem. Just make sure to update the firmware as soon as you get it to keep the AF snappy.

Building on the earlier suggestion, I would suggest being careful with autofocus speed in those dark alleys. I once lost a whole night of footage because a budget lens kept hunting in the shadows under a bridge and it was just heartbreaking tbh. You might want to consider:

• Sigma 20mm f2 DG DN Contemporary
• Samyang AF 24mm f1.8 FE The Sigma feels way more premium than the price suggests tho. Just watch the flare when shooting those street lamps.

Building on the earlier suggestion, i usually play it safe with primes because zooms at this price point tend to struggle in the dark. I used the Samyang AF 24mm f1.8 FE on a night shoot once and it actually held up well despite the low light. It felt sturdy enough for a budget lens. Quick tip: keep a microfiber cloth handy because alley grime is real and wont be kind to your glass.

Been using this for years, no complaints