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.

[deebatman316]

If the lens won't focus again check the rear LCD screen. If the lens is set to AF. The camera will display which AF Operation is being used. The area circled in red below shows the focus mode. Does the lens even try and focus. Or does it NOT attempt to AF at all.

When the lens is set to AF. Your camera will display "One Shot", "AI Servo" or "AI Focus". If the lens is set to MF the camera will NOT display an AF Operation. It will simply display "MF" meaning Manual Focus.

Focus Mode Operation

1. One Shot
2. AI Servo (Servo AF newer cameras)
3. AI Focus
4. MF (Manual Focus)

[ebiggs1]

"Previous response that you should "never use AI Servo" is terrible advice. With action photography you MUST use AI Servo!"

No its not. That is what she is using and if you read more carefully you would have known that. It is why she is missing focus. You guys are tying to confuse a beginning photographer with all the advanced advice. Baby steps, my friend.