Honestly, this thread has covered a lot about the used market and quality control but I havent seen much about the technical compatibility side of things which can be a real headache. You can find a killer price but if the lens doesnt talk to your specific camera body correctly because of an outdated chip or a weird mount issue then that deal isnt really a deal, right?

• Check if the lens is native mirrorless or if it is a legacy DSLR mount because using an adapter can sometimes introduce play or light leaks if the fitment isnt perfect.
• Look up if the lens requires the Tamron TAP-in Console for firmware updates because some older full-frame lenses need that to stay compatible with the latest eye-autofocus tech. I think maybe the Tamron 35mm f/2.8 Di III OSD M1:2 or even the Tamron 70-300mm f/4.5-6.3 Di III RXD are usually priced well under $800 and play much nicer with modern electronics than some of the older adapted stuff. Just be sure the mount matches your body exactly so you dont end up with a paperweight!

Did this last week, worked perfectly

Honestly, I really agree with the point about being careful with what you end up buying. I’m still pretty new to photography stuff, but I’ve been obsessing over how to actually test a lens once it arrives? Like, even if you find a great price on something like the Tamron 70-180mm f/2.8 Di III VXD, you reallyyy need to check if you got a good copy. I've been learning about "real world" performance testing, like taking shots of a brick wall or something flat to see if the focus is even across the whole frame. I think it's called decentering? It’s basically checking if one corner is way softer than the others. I’m always so worried about getting a lens that looks fine on the camera screen but then looks superrr mushy when I actually get the files onto my laptop. Does anyone have a specific way they test their new gear? I’m still trying to figure out if I’m doing it right or if I’m just being paranoid lol. It’s definitely worth doing though before the return period ends!

Unfortunately, my Tamron 24-70mm had issues. Consider a used Sigma; I got mine for $700.

Hey! Black Friday Tamron deals can be tricky. Instead of chasing the hype, might want to consider Sigma Art lenses. Optically superb. The 24-70mm f/2.8 DG OS HSM Art is a beast. Be careful though, check your camera's flange focal distance. It needs to be spot-on for best performance. I'd suggest researching compatibility thoroughly before pulling the trigger.

Check used lenses. Ensure clear glass; $800 isn't worth risking damaged optics.

Skip new; check used markets. Tamron lenses depreciate fast. I snagged a pristine 24-70mm last year for $550. Factor in potential repair costs versus a 'deal' on a new lens. Also, consider lens rental before committing. Might save you money in the long run if you don't use it often.

Black Friday lens deals are tough. Honestly, for $800, consider Sony. My Tamron 28-75mm unfortunately had issues; Sony's G Master series often sees discounts.

Haven't seen lens deals, but for sensor cleaning, I've had good luck DIY with VisibleDust swabs. Just go slow and watch vids! Maybe get a pro to show you once first for safety. Happy shooting!