Okay so I finally pulled the trigger on the a6700 and I am super stressed about picking the right lens before my trip to Tokyo next month. I keep looking at the Sigma 18-50mm f2.8 because everyone says its tiny and sharp which sounds perfect for walking around all day but then I started reading about the Tamron 17-70mm and now I am second guessing everything. My logic was that the Sigma is so light but it doesnt have image stabilization and even though the a6700 has IBIS I'm worried it wont be enough for handheld video while I'm walking through the markets.
The Tamron has VC which seems safer but man it looks massive in photos like it might make the whole setup feel really front-heavy and awkward to carry around my neck for 10 hours. I also saw the Sony 16-55mm G is supposedly the king of these lenses but its way over my $850 budget unless I find a crazy used deal which feels risky right now with my timeline being so tight. I just want one lens that can do everything from street stuff to food shots without me having to swap all the time. Is the extra reach and stabilization on the Tamron actually worth the extra weight or am I just overthinking the IBIS thing on the a6700...
Unfortunately, I had issues with the Tamron 17-70mm f/2.8 Di III-A VC RXD when I took it on a similar trip last year. It was just not as good as expected for long days of walking because the balance is totally off on the smaller Sony bodies. It ends up feeling really front-heavy and kinda ruins the whole point of having a compact camera in the first place. For video, the IBIS on the a6700 is okay, but it is definitely not a gimbal. If you go with the Sigma 18-50mm f/2.8 DC DN Contemporary, you might find the footage is a bit jittery without lens stabilization, which is super frustrating when you are trying to capture cinematic street scenes in Tokyo.
Just wanted to say thanks for everyone chiming in. Super helpful discussion.