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]

Try using P (Program) mode shooting and select the center point for the focus point and one shot focusing mode. See if that improves the focusing with that lens.

[Bankesmom1]

[Bankesmom1]

I can't load any of the good pictures here because it says the files are too big.  These are just a couple of the bad ones.  

[Bankesmom1]

I will give that a try.  However it defeats the purpose of getting good action shots.  Thank you.  And it has worked for years!!!!!!  This is a recent problem.

[Anonymous]

Well, then it sounds like a problem with the Tamron lens. Could the Manual/Auto focus switch on the lens be dirty? You could try repeatedly moving the switch between M and A to clean up the contacts of the switch.

[deebatman316]

Will the lens focus correctly on a stationary subject. If not there maybe a problem with the lens.

[deebatman316]

The metadata reports MF or AI Servo. It could possibly be the AF/ MF switch on the lens. Also AI Servo has NO focus lock. So the camera will fire the shutter regardless of if the subject is in focus or not.

[Bankesmom1]

Thank you for this explanation.  It makes sense.  I'll try these things and just work around the issue.  I'm still baffled why it has worked for years, and all of a sudden does not.  I'm thinking that it is getting to be time to upgrade. 

[deebatman316]

Your lens is the problem. The lens is switch to MF for some reason. Even when you say it's set to AF.

[ebiggs1]

My intention was to make sure you don't associate some cause as the reason for the failure and it not being the correct one. I will bet you "warm" is not the only component going on. It may very well be the reason but I only want to make sure you evaluate all possibilities.

You said later that the lens works using it for football and basketball? Doesn't that almost clear the lens form being faulty?

Another statement I am going to make and please don't think it being rude but almost all focus misses are user caused and not camera/lens. So I am going to recommend you reset your Rebel SL1 back to factory default settings. Also make sure the lens is set to AF. Set your Rebel to P mode. Set ISO to 200 and daylight WB. Very important set the AF mode to One Shot not Ai-servo, never, never use Ai-servo. Large jpeg file. Now go outside on a nice sunny day and shoot some random shots. All kinds of different stuff like trees, buildings, people and pets, etc. Random shoots. Now u/l to your computer and check what you got. If all is well and good there is nothing wrong with your camera/lens combo. If it fails this test one or the other is faulty. This is simple, easy to do and will let you know where the problem lies.

I can't stress enough you do this test. Plus ignore all the other suggestions until you do this test. We have to have a base line to start out with and it is impossible to solve the issue until we do.

How to reset the Rebel, Menu>Tools> Clear all settings and Clear all custom settings. Consult your manual if need be.