I have shot extensively with both lenses on the a7IV body, and in my experience, the Tamron 28-75mm f/2.8 Di III VXD G2 is the superior choice for a trip like Japan where lighting is often unpredictable. While the 28-200 is convenient, the technical trade-offs are significant once you analyze the data. Heres why the 28-75mm G2 wins for your specific use case:

• Aperture consistency: You mentioned Tokyo night shots. The Tamron 28-200mm f/2.8-5.6 Di III RXD drops to f/3.5 by 32mm and f/4.5 by 80mm. Having a constant f/2.8 allows you to keep ISO lower and shutter speeds higher when walking through Shinjuku or Shibuya.
• AF Motor efficiency: The G2 uses the VXD linear motor which is significantly faster and more precise than the RXD motor in the superzoom. When shooting street photography, that millisecond difference in focus acquisition is the difference between getting the shot and missing it.
• Optic resolution: If you are doing landscapes while hiking, you want corner-to-corner sharpness. The G2 is optimized for high-resolution sensors like the one in your a7IV, whereas the superzoom shows more chromatic aberration and softer edges at the extremes. Quick tips for your trip:
• Set the custom button on the lens barrel to Focus Preset via the Tamron Lens Utility software. It is a lifesaver for quickly jumping to a landscape focus point while hiking.
• Dont worry about the lack of VC on the 28-75mm. The IBIS on the Sony Alpha 7 IV Body is more than enough for focal lengths under 75mm... honestly you wont even notice its gone. The 28-75mm hits that $850 budget perfectly and gives you much more professional results for those night scenes.

> I actually found myself wanting more than 28mm for those tight shrine... Agreed, those Kyoto streets are super tiny! You might want to consider the Tamron 20-40mm f/2.8 Di III VXD instead. It hits that $700 price point and gives you the fast f/2.8 you need for Tokyo at night. Just be careful tho, 40mm is kinda short for some street shots. Make sure to think about your range, but honestly, it is so light for hiking.

Building on the earlier suggestion, I totally get why you're leaning toward the 28-75, but I would suggest looking at the wider end of things too. I did a trip through Osaka and Kyoto a while back and I actually found myself wanting more than 28mm for those tight shrine corners and massive landscape vistas. I keep thinking about how many shots I missed because I couldn't go wide enough for the architecture. Be careful with the 28-200 idea tho...

• The aperture drops off so fast. By the time you hit 50mm, you're already losing that sweet low light performance.
• If you're hiking, weight is king, so maybe consider the Tamron 20-40mm f/2.8 Di III VXD paired with a light prime like a 85mm.
• Make sure to test the IBIS performance yourself; I've found the Sony IBIS can be a bit jittery at longer focal lengths without lens-based stabilization. Personally, I'd stay away from the all-in-one zooms if you care about those crisp night shots in Shinjuku. The Tamron 28-75mm f/2.8 Di III VXD G2 is just way more reliable for the actual atmosphere of the trip.