Hello all I'm on vacation for a few days (so no manual with me) and my D300 is acting REALLY strangely. I'll try and explain: Yesterday, I had a 50 1.8 lens on, but this also happened with the 80 1.4, AF-on was not on - was focusing with shutter half down. Tried both S and C settings. I would try to focus on something and the lens would be whirring back and forth like it just couldn't focus. No green dot or beep. Thought maybe I'd accidentally messed something up so I hit Qual/+/- to reset to factory settings and then it would work OK for maybe 3 or 4 shots and then the same thing would happen. In the display I was seeing r26 or r37 or r12 in the space where you usually see how many more shots you can take. I'm sorry if this is a really stupid question but I'm stuck! And I missed a great shot of my parent's last night (we were out to celebrate their 37th wedding anniversary) as the lens whizzed back and forth and all I could see was blurred! :frown: I've just re-set everything again, and I'm thinking I shoudl have the AF-on feature on (just read the sticky and think this is a great feature - although likely unrelated to last night!) One last thing - issue seemed worse when I was trying to focus on subject closer to me, if I focused on something v far away it would work OK Thank you!!!