What are the must-have accessories for a Sony a7IV kit?

Been thinking about your budget. Like someone mentioned, you dont need the flashiest gear. Unfortunately, I had issues with expensive boutique bags; they are just not as good as expected for actual hiking.

• Lowepro Fastpack BP 250 AW III is much better for your back and half the price of the Peak Design one.
• K&F Concept 64 inch Aluminum Camera Tripod is solid for landscape shots without breaking the bank.
• SanDisk Extreme Pro SDXC UHS-II V60 128GB works fine for 4k 60p and saves a ton of cash.

Had a sec... make sure to grab a polarizer for reflections.

• Hoya 82mm NXT Plus Circular Polarizer: great coatings for glare.
• Tiffen 82mm Circular Polarizer: cheaper but watch for flare.

I am literally in the same boat for my upcoming trip to the Alps. Gear anxiety is real when you're managing a 33MP workflow and tight budget. I keep staring at my cart too...

• You might want to consider a Giottos Rocket Air Blaster Large for sensor dust.
• Make sure to get a Sony PCK-LG1 Glass Screen Protector. Just dont forget the blower or you'll be cloning out dust spots for weeks!

TL;DR: Grab a V60 card to save cash, get the full-size Slide strap (not the Lite), and one extra battery because October in the Rockies is freezing. Adding my two cents here, but I have to politely disagree about the V90 cards. Tbh, unless you are shooting All-Intra for professional color grading, those cards are a total money pit for your needs. The a7IV writes 4K 60p at around 200Mbps in XAVC HS mode. That only translates to 25MB/s. A solid Lexar Professional 1667x 128GB SDXC UHS-II V60 handles 60MB/s minimum, so it is mathematically more than enough. You are basically wasting money on overhead you wont use. Use that saved cash elsewhere. Also, be careful with the Peak Design Slide Lite Camera Strap SLL-BK-3. The thin strap might look sleek, but that GM II lens is pretty chunky. I would suggest the standard Peak Design Slide Camera Strap SL-BK-3 instead. It has more padding and wider webbing to distribute the weight. Your neck will thank me after a four-hour hike in Banff. Since it is gonna be cold, make sure to keep your spare Sony NP-FZ100 Rechargeable Lithium-Ion Battery in an inside pocket close to your body heat. Lithium batteries hate the cold and the capacity drops significantly once the temps hit freezing. One spare is probably enough tho, no need for four. For a bag on a budget, maybe look at a Vanguard Alta Rise 45 Backpack. It is way cheaper than the PD stuff but still super protective... shoot me a message if you want more technical specs on the bitrate stuff.

Honestly, I went through the exact same stress before my first glacier trip. I spent hours analyzing write speeds and read-write cycles. I ended up getting a V90 card because I was paranoid about the buffer, but in reality, when I was shooting landscapes and some 4k 60p clips, the V60 cards I already had worked perfectly without dropping frames. It's more about the sustained write speed than the peak. Regarding the cold, I learned the hard way that:

• Batteries lose about 30% of their effective life once it hits freezing. Keep them in your inner jacket pocket next to your body heat.
• Two spares are usually plenty for a full day of hybrid shooting if you're smart with power settings.
• Carrying a heavy setup on a thin strap for eight miles is a nightmare. I switched back to a wider, more padded option because the sleek one just didnt distribute the weight properly on long treks.