Where to buy a used camera or lens
Dealers give you grading and a return window. Marketplaces and forums give you range and lower prices. Search both before you buy.
Dealers
Used dealers such as KEH, MPB, B&H, and Adorama inspect, grade, and warranty what they sell. You pay a little more for that certainty, and you can return gear that arrives wrong.
Grades differ by dealer, so read each one's grading guide rather than comparing labels across shops.
Marketplaces
eBay has the widest selection, including many experienced exporters in Japan. Check a seller's feedback, read the full description, and look for clear photos of the glass and the shutter.
Mercari, Etsy, and local listings can turn up bargains, but most sellers are not camera specialists. Ask about haze, fungus, and shutter speeds before you pay.
Forums and auctions
Buy and sell forums such as Fred Miranda and r/photomarket are run by enthusiasts. Read the forum's rules, check the seller's history, and pay with a method that offers buyer protection.
Auction sites such as Catawiki and Yahoo Auctions Japan, through proxy buyers like Buyee, add fees and shipping on top of the hammer price. Count those before you bid.