I usually skip the massive marketplaces and hit up places like Adorama or Focus Camera instead. I remember when I was first building out my kit, I got obsessed with the technical specs and spent hours comparing line pairs per millimeter. I ended up buying a lens from a smaller boutique shop during a holiday sale because they offered a free calibration service. It really taught me that a lower price tag on a big site isnt always the best value if the glass isnt perfectly centered for a high-res sensor like the one in your a7R V. Those 61 megapixels are pretty unforgiving, so I always check if the shop has a solid return policy in case the copy you get has some decentering issues. Ngl, sometimes the refurbished units directly from the manufacturer or dedicated sites like KEH are the real hidden gems during these sales windows tho. I learned that checking the specific manufacturing batch can actually matter for autofocus consistency on the newer bodies.

Just check Amazon, B&H Photo Video for Black Friday deals, they will offer free accessories.

Can confirm