Hi there! Well, since the a7S II has an older AF system, you really need a lens with a linear motor to avoid hunting. For your $800 budget, I'd go with the Sony FE 35mm f/1.8. It's super reliable and honestly sharp wide open. If you want that f/1.4 look, the Sigma 35mm f/1.4 DG DN Art for Sony E is amazing, though it's a bit heavier for handheld work. Personally, I think the 35mm is safer for street stuff! Hope this helps!

> I’m currently torn between a 35mm or 50mm focal length, but I'm a bit worried about autofocus hunting in dim settings.

I totally get that concern! Since the a7S II relies on older contrast-detection AF, you really have to be careful about lens choice to avoid hunting. For a safety-first approach, I’d suggest the Sony Zeiss SEL55F18Z FE 55mm f/1.8 ZA.

Honestly, it’s a bit of a legend for a reason. While some newer f/1.4 glass looks tempting, the native linear motors in this Zeiss lens are incredibly reliable and snappy, even in dim venues. It stays sharp wide open, which is exactly what you need for those indoor events. I’ve found that using third-party lenses on older Sony bodies can sometimes lead to unexpected focus drops, so sticking with native glass is definitely the more conservative, reliable play here. It fits right in your budget too! Just make sure to keep your firmware updated to help the AF along. Good luck!

Hi there! I totally get the struggle with the older contrast-detection AF on the a7S II. In my experience, even with an f/1.4 lens, the body can struggle if the lens motor isn't snappy. Since you're on a budget, you might find this useful—check out the "DXOMARK" lens database or the "Dustin Abbott" review site. They have specific technical breakdowns on chromatic aberration and sharpness wide open for the E-mount system.

From a technical standpoint, I'd suggest looking at the Samyang AF 35mm f/1.8 FE. It's often overlooked but has a very fast linear actuator that handles low-light hunting much better than the older Sigma Art glass. Also, pro tip: if you want to push that $800 further, keep an eye on KEH Camera or MPB for used copies of the Sony FE 35mm f/1.8. Buying used lets you snag a high-quality Tiffen 55mm Variable ND Filter too, which is honestly essential if you ever transition from those dark indoor events to street shooting in daylight. Hope this helps!

Did this last week, worked perfectly

Saving this whole thread. So much good info here you guys are awesome.

Seconding the recommendation above! The Sony FE 35mm f/1.8 is a fantastic choice for the price. That said, I've spent a lot of time shooting in dark venues, and you might want to consider the Sigma 35mm f/1.4 DG DN Art for Sony E too. It's right at your $800 limit, but that f/1.4 aperture really helps the Sony a7S II sensor shine. Just be careful with the older autofocus system—third-party lenses sometimes hunt more in low light compared to native glass. Anyway, hope that helps!

Bookmarked, thanks!

For your Sony a7S II, the best low-light primes balance fast apertures with reliable autofocus to complement its legendary high-ISO sensor.

Sony FE 55mm f/1.8 ZA – A native lens legend with snappy linear motors that minimize hunting in dim conditions, critical for the a7S II's contrast-detect AF. Tack-sharp wide open with beautiful rendering.

Sony FE 35mm f/1.8 – Excellent all-rounder with fast, quiet AF and compact size. Perfect for street and indoor events where 35mm's wider view works better .

Sony FE 50mm f/1.8 – Budget-friendly option at around $250 used. Affordable, sharp enough, and pairs beautifully with the a7S II for night work . Autofocus is slower than premium options but usable.