saw this earlier today and just getting a chance to weigh in. i remember my first big trip to a city like nyc, i brought a massive setup and basically spent the whole time worried i was gonna drop it or get it swiped because it stood out so much. honestly, ive been so satisfied since i started prioritizing smaller, more reliable glass that doesnt scream tourist at everyone. i ended up picking up the Sigma 35mm f/2 DG DN Contemporary for exactly this reason. its got this all-metal build that feels super solid in the hand, which gives me a lot of peace of mind when im navigating crowded streets or subway stations. im really happy with how it balances on the a7iii. if you look at the market right now, you can easily snag one of these used for under 500 bucks, which leaves you a nice chunk of change for your trip. i also looked at the Sony FE 28mm f/2 when i was comparing brands. its a bit of an older lens, but man, it works well and is incredibly budget-friendly. you can usually find it for around 250 or 300 used. its not quite as sharp as the sigma but for street photography, its plenty good and very discrete. ive never had any complaints with the autofocus on either, though the sigma feels a bit more robust for long-term use. keeping things simple and staying under budget makes the whole experience way more fun... you wont be stressing about the gear so much.

Quick question tho, you gonna be out shooting if it rains or just clear days? NYC can get messy. Im really satisfied with the Sony FE 40mm f/2.5 G because the weather sealing is legit. Tip: stick to lenses with dual linear motors for reliable focus in crowds. Cheaper glass hunts too much when it gets busy... you dont want to miss a shot because of slow AF.

just grab the Sony FE 35mm f/1.8 and dont look back! its absolutely fantastic for street and easily fits under your 600 buck budget. i use it on my a7iii all the time and the autofocus is just lightning fast. honestly its way more discrete than that zoom brick. you can find them for like 450 bucks new... total steal for the quality you get!

if you really wanna save some cash for the trip, check out the Samyang AF 35mm f/1.8 FE. its way cheaper than the sony version and weighs basically nothing. build is kinda plasticky tho. still, it gets the job done for street stuff and wont break the bank. save the extra money for some good pizza in the city lol.

i totally get why youre ditching the zoom. the a7iii is a beast but that 24-70 is a brick for street stuff. ive been using a few different primes lately and honestly im super happy with the performance of the smaller g series glass. they actually fit the body perfectly and dont scare people off like a massive lens does. for your nyc trip here are a few specs-heavy options that work well and fit your budget:

• Sony FE 40mm f/2.5 G is my top pick for being subtle. it only weighs about 173g and the dual linear motors are dead silent. the 40mm focal length is a nice middle ground between 35 and 50. i have had no complaints with the corner-to-corner sharpness even at f/2.5.
• Sony FE 35mm f/1.8 is another solid choice if you want that extra bit of light for night shots. its about 280g so still light and the af tracking is incredibly snappy. it stays right around your 600 bucks price point.
• Samyang AF 35mm f/1.8 FE is a great alternative if you want to save money. its basically plastic but its super light at 210g and the optical performance is surprisingly high for the price. stick with the 40mm g lens if you want the smallest footprint. it is basically a pancake lens compared to what youre used to. nobody even looks twice when im shooting with it in crowded spots... plus it has an aperture ring which is nice for quick adjustments.