Bigma Owners, Focus Question

[rogerdaltx]

I picked up a Bigma the Sigma 50-500mm EX second hand from a local guy about three months ago; he bought it from

a local pro camera store. I've only had it out three or four times. What I thought at first was a quirk I'm now

thinking is a defect with my copy. Optically everything is fine, but I'm having autofocus issues.

 

The autofocus frequently stops working like it's disengaged. You can hear the k20d focus motor spinning but the

lens is not focusing and no elements are moving. The Bigma has something similar to Pentax's quick focus clutch.

If I pull the focus ring back to switch to manual focus, manually move the ring a bit then push the clutch ring

forward to re-engage autofocus AF works again; for a while. This exercise has to be repeated frequently.

 

In theory the three year Sigma EX US warranty should be in effect, but being the second owner I may have issues

there.

 

Have other Bigma owners or owners of similar Sigma Tele zooms with the quick shift focus ring seen similar issues?

 

Thanks

/Roger

[jgredline]

Roger, I have the bigma as well, but confess my son has started to use it far more than I ever did. The slow auto

focus drives me nutz..But as for the clutch, I do not recall ever having a problem with that. It snaps solidly

into place.

 

On the rare occasion that I do use it, I only do manual focus as does my son. I also do not believe Sigma has a 3

year warranty. I believe it is for one year. Their customer service though is top notch in my experience with

them...

 

<img src="http://i404.photobucket.com/albums/pp128/jgredline/family%20pics/danielwiththebigma.jpg">

[michael_elenko]

Javier,

 

Sweet shot; that lens+hood is longer than your son is wide.

 

Roger,

I've only owned a Bigma for a few weeks now, but I haven't had any issues with AF-to-manual focusing changeover. I don't mind the AF performance, but I always finish with manual focus tweaks on any telephoto shots anyway, so it is natural for me to stay with manual focus.

 

I know that the Bigma's manual focus clutch is confusing for many new users; perhaps a prior owner or potential owner stripped some gears?

 

ME

[ian s. forsyth]

Roger If the lens was purchased in Canada you might have a 10 or 7 year warranty