FYI: I don't use a clip on diffuser, the batteries are fresh and the flash is auto TTL mode. Strange that it will not work at times and then rare times it does. ????

Thanks everyone for your input. BTW: I just turned on my SB900 and it was syncing up with my 18-200 mm lens again tomorrow it might not. johnnyapple I will need to look up the focal length information to see if that info is being stored in the exif data.

Check your batteries... The Sb900 will have a slightly off response when it is near death... Also make sure the contacts are clean.

Are you using the on-board diffuser or the clip-on diffuser dome? Either of those will lock the SB-900 zoom head to 14mm.

is there a chance your flash is set to manual zoom?

I don't know what would cause that, Marc, but could you let us know whether the focal length information is being stored in the exif data of the pictures you take with the 18-200? That way you would know if the lens isn't communicating it to the camera. I'd think that's the first place to look. Welcome to the forum.

HI all, I was hoping that someone might be able to help me figure out why my flash is not syncing up properly with my 18-200 mm Nikkor lens. I have a SB 900 Nikon flash and sometimes it will sync up with my D7000 and my 18-200 mm Nikkor lens but most of the time it will not. I have always tried to make sure my D7000 is off (sometimes forget to turn off) when I attach my SB 900 flash. I also try to make sure the flash is off when I disconnect or connect it to the camera body. I will then start up my D7000 and then switch on my flash. First thing I will do is move the 18-200 mm lens in and out to see if the flash has connected or synced up to the lens. When the flash syncs properly the flash's internal lens will automatically adjust the focusing of the light (in or out) with the lens zoom range.

Is there anything I can do to correct this problem? I recently updated my D7000 firmware but that didn’t seem to help correct that issue… HELP