My wife helps put on a big trail running race, mountain bike race, and climbing festival here every Memorial Day weekend. It's become pretty popular but entries need to be capped to preserve our trails and the community feeling of the event. This year the bike race sold out (350 racers) in 7 Minutes back in January. I've done it the last two years but decided this year to try shooting it and seeing if I can get published or at least sell some images to the racers. Since my DAL 55-300 is just ok, I decided to rent the 50-135 from cameralensrentals.com for this. It looked funny on my K-x. I'm so used to small primes that this lens looked like a behemoth on that little body. But I don't really care how my camera looks, so no big deal there. It does add considerable size and weight too, which is more important to me. I would have a tough time putting this thing in my bike backpack for shooting while on a ride like I do with my primes. This is the first SDM lens I have used and I have to say it's pretty nice. It may not actually be faster but being quieter makes it seem so. Most of my shots came out in-focus pretty well using AF-C and the auto 5 point setting. I guess I could have sat in one spot and just shot everyone from there but that gets boring for me and produces boring shots IMO. I know these trails very well and know how to combine driving the jeep trails with running/hiking to get to the spots I wanted to hit, so I went to four different spots for the bike race. I used the running races as a test/warm-up the day before so I didn't hit as many spots or get as many photos as with the bikes. I used the 50-135 for most of the shots, only putting the da15 on for a few atmospheric wide shots. The light was nice in the morning but as the day progressed it was pretty challenging at times. The lens was easy to handle for what it is and once I got used to the zoom & focus ring locations it felt very natural. I took about 3300 photos over the weekend which is a lot more than I usually shoot. I sun burned the inside of my left forearm because I'm not used to having it facing up (supporting this big lens) and never put sunscreen there. I also went through three sets of Eneloops a day which seemed like a lot. I'm thinking the AF-C and bigger lens must have also contributed. I started in RAW but had to switch to jpeg so I wouldn't run out of space but still filled a 16GB and most of an 8GB card just with the bike race. To my eyes the results look pretty good. I set up a Zenfolio site (still on the trial period) to sell the images and the race organizer (Dave Wiens - a mountain biking legend) hasn't sent out the links to the racers yet, so there haven't been any sales but I'm hopeful. Here's a couple of examples of my friends I posted to Facebook (so there is some loss of quality) to generate some interest: So in short, the lens is just as nice as everyone says. I liked using it but I'm not convinced it's worth the asking price for the amount of use it would get from me. Of course if I sell a lot of these shots, I may change my tune but I'm not holding my breath for that to happen! If you have made it this far, I'll add that my Zenfolio site with all the racer photos that made the cut at mattburt.zenfolio.com. If this is successful I'll probably integrate that with my existing site for a more seamless experience.