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.

[Anonymous]

Is it only this lens, or does it happen with other lenses? 

Try removing and re-installing the lens to wipe the lens contacts.

[deebatman316]

Do you have any Canon lenses. If so do they fail to AF in warm weather too or just the Tamron lens. Also what is the full model name of your Tamron lens. Also the Full model name of the Canon lens if you have one.

[Waddizzle]

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@Bankesmom1 wrote:

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.

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If the camera will not “close focus”, then you may need to verify the Minimum Focus Distance.  The MFD should be written on the lens somewhere.  If not, look the specs up online.

Please note, the listed MFD for the lens is only valid at the minimum zoom setting.  As you increase the focal length, the MFD will also increase by an amount manufacturers do not like to reveal.

[kvbarkley]

If this is the 150-600, sometimes I need to "kick-start" it by focusing on something closer, and then focusing back on my subject.

[ebiggs1]

Causation requires that there is an association between two variables, but association does not necessarily imply causation. Meaning are you sure it is warm or hot weather that causes the AF problem? How much shooting do you do in cold or cooler weather?

"...sometimes I need to "kick-start" it by focusing on something closer, ..."

I have also seen this phenomenon in some off brand lenses. You may want to try this. Minimum focus distance can also be a factor. Objects in the way of the focus point can fool the AF system.

The thing I would doubt is warm weather causing it.

Tyr this..........

I would reset your camera to default settings. I would make sure you have a good fully charged Canon brand battery. Do not use off brand batteries. It could be as simple as a faulty battery especially in warm (hot) weather.

[kvbarkley]

Warm weather causes it since that is the time when you are more likely out taking photos!

8^)

[ebiggs1]

For sure. Cause and effect, drawing incorrect conclusions.

[Bankesmom1]

This is the only lens that it happens with.  It is the only Telephoto that I have.  It is a Tamron18-270mm F/3.5-6.3.  My other lens is a Canon EFS 18-55mm and I never take it to sporting events because things are just too far away.  And I've never had an issue with the Canon lens. 

[Bankesmom1]

I do have a Canon lens and it is an EFS 18-55.  It has never failed to auto-focus.  I never take it to sporting events though.  Just inside mainly when things are relatively close.  The Tamron is a 18-270 mm F/3.5-6.3  Thanks for your questions and trying to help me solve this issue.