This is second post I've read in as many days where a wedding guest/ friend/ relative is planning to show up and help photograph a wedding (sometimes with a bag full of pro gear)- and they aren't the official photographer. As a professional wedding photographer for 10 years, nothing makes me groan more. Please, please, please if you want to be the photographer for someone's event, ask them or if they ask you, take on the whole job. I feel badly already for the official photographer at this wedding- god forbid she only has a crop camera. If you perceive this photographer as less than 100%, it's not your job to show up and prove it with rented gear. Your friend hired her- period. They will live with the good, bad, and ugly of their choice. Do they have twenty pizzas showing up in case the prime rib sucks? I doubt it. I know people enjoy photography as a hobby and there are some very good hobbyists out there. It's fun to rent gear and it's fun to shoot when there's no pressure. The official photographer doesn't have these luxuries. Want to know a secret? Being a professional wedding photographer has little to do with cameras at all. It's smiling, putting a nervous bride at ease, coordinating a drunken bridal party of 14 into a photograph, taking photos with a dozen iphones over your shoulder competing for your subjects' attention, chatting gear with hobbyists without wasting time or missing shots, it's projecting confidence, being well groomed, being in the room when something happens, staying on your feet for 10 hours with two heavy cameras weighing you down, it's getting a club sandwich while guests get surf and turf. It's downloading, backing up, editing for hours, album design and redesign and redesign. it's paying an assistant, business insurance, marketing, payroll, taxes galore, equipment repairs and maybe myself. We do it all for that little rush of composing a photo and making people smile and swoon when they enjoy your artistry. We do it because we can't do anything else. So go, have fun, take photos, just show some respect and understanding for what the "official" photographer has on their plate. Sorry, I had to vent a little- or a lot. To play along nicely, I'll add that I use a 16-35 LII and a 50 1.2 or 85 1.8. I really wish they made a 65 1.4 or a 50-80 1.8 zoom- that would be sweet.