I love Action Camera in Roseville. I stopped by there late this afternoon to have the sensor on my Nikon D800 cleaned; there were some spots on it that tend to show up on photos that include lots of sky and, at Action Camera, they cheerfully clean sensors and dispense advice and information at no charge. Today, Pete, one of the knowledgeable sales people who was excited to fondle my D800 when I first got it there a few months ago, cleaned the sensor and discovered that my UV filter had come apart. Yesterday I noticed a rattling and wondered what was loose. Luckily I had bought a filter that could be reassembled and he put it back together again for me and advised me to keep an eye on it. Although it was made to reassemble, it is apparently not a common occurrence. But, the most exciting piece of advice I got today involved focus points. I had asked if I was being paranoid and imagining things about the auto focus problems that have bee reported with the D800. He told me that I could actually make many adjustments using the menu system to fine tune the auto focus system. I was clueless that there were so many options and I plan to spend tomorrow studying them. But for now, the most exciting thing I learned is that I can actually group focus points to make the camera more responsive to auto focus on an area. And, it seems to work! I used my new found knowledge for today’s shot, grouping a cluster of auto focus points. I focused on a leaf that was laying on top of the fountain. Since it was getting dark out, I also used the on camera flash, with flash compensation set to -3.