To add to the point above: I really think you should be careful with that Sony FE 50mm f/1.8. Tbh, on your a6400, that 50mm acts like a 75mm lens... its way too tight for chasing a toddler around a park unless you're standing like twenty feet away. Plus the autofocus really does struggle like people say. I'd actually disagree with the idea of sticking strictly to primes for street and kids when you're just starting back up. Primes are great but they can be a bit of a trap if you only have one and your subject is fast. If you can stretch that 400 dollar budget by maybe fifty bucks or find a used deal, please look at the Sigma 18-50mm f/2.8 DC DN Contemporary. I know it's not an f1.4 prime but f2.8 is still a massive jump over your kit lens for low light and the background blur is still solid. It's tiny, the autofocus is way more reliable for video than the older Samyang stuff, and you wont be constantly switching lenses while your kid is running away. Plus it has a bit of weather sealing which is nice for that Seattle mist. If you really want a prime and the Sigma 30mm feels too risky for video, the Samyang AF 35mm f/1.8 FE is actually a sleeper hit. It's technically a full-frame lens but works great on the a6400. It's quiet, fast, and light. Just make sure you update the firmware if you get it used because the early versions were a bit buggy. Just my two cents tho... dont rush into the 50mm just cause it's cheap.

> The Sigma 30mm f1.4 looks great in the samples but then I read a few threads saying the autofocus can be a bit jumpy I totally get the hesitation with the Sigma. Honestly though, I've been super happy with the Sigma 30mm f/1.4 DC DN Contemporary Sony E for years and the AF issues are mostly overblown if you just update the lens firmware. It works well for most things, seriously. But if you want rock-solid video, the Sony E 35mm f/1.8 OSS is a beast. It has Optical SteadyShot (OSS) which is a lifesaver since the a6400 doesnt have in-body stabilization for those rainy Seattle street shots. Another sleeper hit is the Viltrox 33mm f/1.4 AF STM Sony E. It feels really premium and the AF is surprisingly snappy for the price. If you want to nerd out on technical specs, check out the lens database over at DPReview or look up Christopher Frost on YouTube. He does great side-by-side comparisons that show the real-world differences. You really cant go wrong here... both are solid picks.

@Reply #3 - good point! That crop factor really trips people up. If youre doing the Seattle park thing, you might want to consider the Sigma 16mm f/1.4 DC DN Contemporary instead of the 30mm. It is wide enough to keep the toddler in the frame even when they are running right at you, but be careful because it is a bit heavy and might make the a6400 feel lopsided. I remember being out at Discovery Park last October trying to get shots of the lighthouse. It was one of those typical grey days and the wind was just whipping off the water. I got so distracted watching a huge heron trying to land on some driftwood that I actually tripped over a log and almost face-planted. I was way more worried about my gear than my actual knees, which is probably a bad sign lol. Spent the whole hike back just cleaning sand out of my socks and thinking about where to get a decent burger. Anyway, the Samyang AF 12mm f/2.0 E is another solid budget option if you want something even wider for street architecture. But yeah.

TL;DR: Stick to the used market to save cash because toddlers are basically chaos magnets for expensive gear! @Reply #2 - good point! That crop factor on the a6400 is no joke and you really have to calculate the effective focal length to get the FOV you actually want! I absolutely love the technical specs on Sony's real-time tracking, it is seriously amazing how the algorithms handle eye detection these days! But man, speaking of the park, have you been to the Ballard Locks lately? I went there last week and got completely distracted by the salmon ladder. I ended up just watching the fish for like three hours instead of shooting. There was this one sea lion just hanging out waiting for a snack, and I totally forgot I even had my gear with me. I spent the rest of the afternoon reading about fish migration patterns on my phone while eating fish and chips nearby. Nature is just so fascinating when you actually stop to look at it! Anyway lol, sorry kinda went off topic there.