I just posted some of the shots here (http://www.canonrumors.com/forum/index.php?topic=12641.msg376869#msg376869
I had a great time shooting, and here are some of the things I observed- keeping in mind that this is my first equestrian anything, let alone shoot:
1. Dressage might be really beautiful, but to the uninitiated, it's not too exciting after you've seen one or two routines.
2. Watch the riders in each event/class run the course once to understand which direction they're going and which obstacles they are going to jump. Don't be a rookie (like me) and point your lens at the wrong jump or wrong direction.
3. Walk the cross country course (with the riders at the designated time) and have a good map. Mark the jumps by direction and amount of shade so you know which obstacles to shoot in good and bad light. Shoot open obstacles early and late, shaded obstacles during the day. Read the press materials to find out which jumps are the toughest and most visually interesting.
4. Shoot in Manual mode - 1/1000s minimum - 1/1500s or higher ideally. Unless you have a 1DX, set the ISO until you have a shutter speed around 1/2000s to 1/4000s so you adjust the shutter speed to compensate the exposure for white horses, dark horses, light and dark outfits. Expose for skin tones of the rider.
5. Focus on the rider's face. I shot wide open (f/2.8 bare, f/4 with 1.4x extender). From the side, it's enough for full focus. From the front/angle, it's not really enough to get the rider and horse's faces in focus, but it was a judgement call to blur out the very distracting background elements.
6. For show/stadium jumping, it's best to shoot one jump at a time versus following the rider around the course. Pre-focus on the middle of the obstacle, wait, shoot multiple frames at high speed drive.
7. For cross country (and dressage), set Case 2, 61-point automatic selection AF, and set the initial AF point to where the rider's face will appear near the obstacle. Pre-focus in that area, wait for the rider, with your finger on the shutter and thumb on the (back button) AF button. When the rider enters the frame, lock focus and fire away in high speed drive mode. With the 5DIII, as long as I locked on successfully, I had a 90% or better success rate tracking over 20+ frames.
8. Even spectators can get very close to some jumps - pack a 24-70 and 70-200 + 1.4x minimum. Everyone and their brother (read spectators) had a 70-200, so I shot most of the events with a 300mm with and without extender to get a cleaner background and a more unique perspective. The compression helped with the focus as well. I shot closer jumps with the 24-70 and some jumps forced the 70-200 into action based on the shooting location.
9. As recommended above, shooting low helps. Also, shoot different angles, other than directly behind the horse.
10. Mid-day light, when most of the action happens SUCKS and you can't use a flash or any other lighting (for the rider's safety). Find a shaded obstacle, shaded galloping lane, or try to shoot backlit riders, which means getting low and finding a decent angle so the sun is at least at a slight backlit angle. The backlight will give you less exposure differences between skin, clothes, and shadows vs. frontlit.
11. Polarizers are very helpful for wet jumps, to slow shutter speeds (as an ND), and to reduce the harshness and contrast of the mid-day sun. The drop in C-PL for the 300mm was very helpful.
12. Make sure you print and save the ride times sheets each day. While most of the riders wear bibs or have their numbers on their horses, many of them do not, particularly in the stadium jumping. Also, many of the competitors ride multiple horses, making identification/captioning all the more challenging.
13. Find out who the favorites are and (see #10) know when they are supposed to ride. I ended up taking lunch breaks, meeting with others, etc. when the overall winner rode and I didn't get a single photo of him - fail!
Overall it was fun, and I'm excited to shoot it again next year. Here the links to more of the photos:Red Hills International Horse Trials Day 2Red Hills International Horse Trials Day 3