EOS SL1 auto focus doesn't work. Seems to happen on hot days

[Bankesmom1]

My Rebel SL1 with a Tamron telephoto lens won't auto focus on warm days.  It will sometimes work at close focus, but when zooming in, it won't auto focus. Does anyone have an answer to this.  Same thing happened last year, but my local camera shop could give me no answers.  It was the shop where I purchased the camera, and I was disappointed with their response.  The weather has warmed up, I wanted to take pictures at a grandson's baseball game and no autofocus.  Frustrating.

[Bankesmom1]

I wasn't certain that I had reset to factory settings so looked at a YouTube video to do that, and then followed your instructions again.  This time there were 3 times when the lens did not want to focus at a distance.  I pushed the shutter release halfway for it to focus, and it did not.  There was some clicking like noise going on, but it would not make the exposure.  Then I took my finger off the shutter button tried it again and it did take the exposure.  I also noticed on various shots that not all of the red lights were lighting up in the view finding when focusing.  

[deebatman316]

When this happens again check the rear screen of the camera. Then see if it says AF or MF. 

[Bankesmom1]

OK.  I will check the screen.

[deebatman316]

Your out of focus pictures report MF according to the metadata. Not any AF operation.

[Bankesmom1]

I tried to find that in the rear lens when it was happening at the ballfield last night, but I could not find where it is located on the rear screen.

[ebiggs1]

"I also noticed on various shots that not all of the red lights were lighting up in the view finding when focusing."

This could be because you didn't turn off all the other focus points. You want just the center focus point to be turned on. Consult your manual or YouTube if you don't know how. This is probably the reason you are having trouble. You are giving the SL1 too many choices and it can't find one that works. Use just the center point an One shot AF.

Please ignore all other advice and suggestions until we get this sorted out.

[Anonymous]

"Please ignore all other advice and suggestions until we get this sorted out.

EB"

Wow!

[ebiggs1]

Too many suggestions can only confuse her. We have to have the camera back to basics and with known settings to analyze the problem. Then start the process to determine whether it is the camera or the lens or both or her. This is basic troubleshooting, my friend.

[Bankesmom1]

Two nights in a row, I've done what you suggested.  Everything is back to factory default, P mode, and it is still happening.  Quite frequently last night. I changed it to center focus too. So what do you think I should do now?

[Bankesmom1]

OK.  I've downloaded last night's shots and I did get some great ones.  I'm happy with the clarity and focus of what I got.  The same thing happened last night again, several times.  It would not focus when asked to do so.  So there goes my heat theory out the window.  Thanks so much for sticking with me and helping me to realize that it is not the heat.  Everyone's advise has also convinced me to no longer use sports mode, just the P mode for now, until I become more knowledgeable.  Ebiggs1, you have been so helpful to me, and explained things in such detail.  Thank you for that.  My next goal is to find how to turn on just the center focus point.  Is it your conclusion that the lens is faulty after last night's experience, and also experiencing the issue several times yesterday afternoon also?