Thursday, June 14, 2012
Heh. I just saw that I had 177 page views last month. Thom Hogan's ByThom.com website probably generates more than that every ten minutes! If you need to know more about the Nikon cameras, he is da man! I have to publicly thank him for help in diagnosing my Sigma 70-200mm f2.8 EX DG HSM OS issues last week. It turns out my three-month-old lens lost all of its internal programming. It went from focusing on-point all of the time to requiring +5 AF Fine Tune at 85mm and 100mm, and -15 at 200mm! C.R.I.S. Camera in Chandler, Arizona is now looking at it under warranty. I expect to have an update on it today. Hopefully it doesn't require parts (AF module) from Sigma, but I fear that will be the case. When an electronic device loses its internal pre-programmed memory for some unknown reason, it is almost a sure bet that simply stuffing the programming back in will not work. My first Sigma 70-200mm lens did the same thing, and the work order from Sigma indicated they had to replace the module. I do find it interesting that the lens can be programmed to automatically correct for front/rear focus issues. This suggests to me that there is an internal group of elements which has its own small motor drive, which is used to tune the lens on a sliding scale from 70mm to 200mm. Maybe with a zero point at 105mm or something like that. I'm truthfully not sure how they do it but I find it fascinating! I also want it to work properly from now on. There's not much worse than getting home from a single day car show and finding out that some of your shots that you thought were fine were instead complete garbage. It is hard to make a living that way.