Question - What causes the Canon Rebel XS / XSi to focus hunt?

[The Stigenator]

It has happened twice. I first thought it was due to the cold weather (it first happened when I was in Disneyland 2 weeks back). It happened when it got really cold.

This afternoon it happened again.

The only common thing I noticed was that I was using the same lens Tamron 28-75 f.28
However like last time I ended up resetting the camera and then pulled the battery out for a bit, but unlike last time, it continued to do it.

So I pulled out another lens and it did it on that one too.

Basically the camera button will not trigger in auto mode, it wont focus. It will zoom in and zoom out but nothing more. You have to go to manual focus to activate. Any clues> I am on the latest firmware. I have to check if that is under factory warranty or not. Time to call Canon tomorrow I guess.

 

[Suspicious-Teach8788]

What were you focusing on? Single point? 9 Point? Remember how AF works. The center point is crosstype, but the others aren't. So are you focusing on an object where the edges/lines/features run through the AF points?

 

[The Stigenator]

I tried both center, and 9 point. The camera wont light up the focus point, the camera just focuses in and out (not zoom) and doesnt lock on to anything.. I had multiple objects, and enough light and distance.

What was funny both times my canon EX 430II was mounted on it. I am wondering if that has something to do with it. Though it should allow focusing easier with the focus assist lamp.

 

[angry hampster]

Use one-shot focus. You're using a lens that is slow to focus on a camera that is slow to find focus.

 

[timswim78]

Use one-shot focus. You're using a lens that is slow to focus on a camera that is slow to find focus.

My thoughts exactly.

 

[The Stigenator]

I double checked. It's on one shot mode.

Next suggestion.

 

[The Stigenator]

I called Canon. Their opinion, its under warranty, send it in.

So the camera gets shipped to canon today.

 

[The Stigenator]

My thoughts exactly.

Actually I tried 3 different lenses. Tamron 28-75, EFs 18-55 and EF 50 1.4 none are slow to focus honestly.

 

[angry hampster]

Actually I tried 3 different lenses. Tamron 28-75, EFs 18-55 and EF 50 1.4 none are slow to focus honestly.

None are slow to focus? Compared to what? I'm not trying to be a snob, but I think you may be expecting too much.

Is this a problem that has recently developed, or something you've experienced since you purchased the gear? Did you buy your equipment all at once, or one piece at a time?

 

[twistedlogic]

Actually I tried 3 different lenses. Tamron 28-75, EFs 18-55 and EF 50 1.4 none are slow to focus honestly.

Sounds like its the camera body.

Have you tried cleaning the contacts on the lens mount? My Tamron used to have issues that you describe except it wouldn't AF at all, but it was only that lens. Unmounting and remounting the lens would fix the issue.

And have you tried doing a factory reset, defaulting all your settings to factory?

 

[The Stigenator]

Yes I checked the contacts on the tamron, and I also cleaned the contacts on the tamron / and body. However the problem is that the issue happens on all the lenses I tried it with.

I reset everything to factory, that didnt help. The only thing that gets it back up and running, take out battery for a few minutes. The battery is a factory canon battery.

This problem recently developed, since I have over 6000 shutter actuations on it, and the fact that the other bodies do not show this problem (40D, 30D) I know it was not the lenses. I think there was a failure in teh AF system. We shall find out what canon says but the looks of it the AF system was having a bad day.