AF hunting - Sigma 150 - 500 (Nikon)

[baturn]

My 5 yr. old Sigma 150 -500 on my nikon D300s suddenly started hunting. Tried cleaning contacts, fresh battery, etc. Was working yesterday. Went out to shoot some backyard birds this AM and Crap! Any ideas?

 

[manicmike]

I had a 150 500 that did the same thing just before the focus motor crapped out.

 

[baturn]

Did you get it repaired? If so, how much?

 

[manicmike]

Yeah, had it backfrom Sigma in less than a week. It was under warranty so it was free. I'd contact their customer service.

 

[Derrel]

Well, Sigma has had tgo reverse-engineer the AF systems in all of their lenses for Nikon. As Thom Hogan wrote earlier this week, at Thom Hogan's Nikon Camera, DSLR, Lens, Flash, and Book site

"... if you want make compatible lenses for the F-mount, you have to reverse engineer the mount (and there are an incredible number of subtle changes that have occurred to signals on that mount over the years as cameras and Nikon's own lens technology changed). Rumors abound that Tamron has gotten some inside help with the F mount, apparently due to licensing lens designs and doing some manufacturing for Nikon. Tokina was formed by ex-Nikon engineers. Sigma took the total reverse engineering approach and sometimes gets burned by it (a lot of their lenses have needed firmware updates when new cameras come out)."

With the above thoughts in mind--maybe you've made an adjustment to the focusing system and how you have it set up? Perhaps you adjusted, or re-set the AF-ON button's behavior option? Or something similar?

If the lens was bought five years ago, it very well might have been manufactured six years ago, and as such, it *might* not have the same AF reverse-engineered protocols that are needed for the roughly five-year-old D300s. Have you tried a two-button re-set of the camera, to bring it back to the defaults? There are so,so many AF system adjustments in a D3 or D300 series camera; the D200 that came before, just as an example, brought a new AF-ON system to the mid-level Nikons, and thousands and thousands of Sigma HSM lenses were in effect, "broken" when the new AF protocols were implemented on the D200.

 

[baturn]

T hanks for the responses. Ive been using this lens on this camera for about a year. It was working fine yesterday, this morning not so much. Will try the 2 button reset and then reset tomy preferences one at a time. Sigmas service center isn't open til Mon.