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]

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

[Bankesmom1]

This actually did not work.  It still did the same thing.  I accidentally clicked the wrong box, and I can't un-click it.  Still had many difficult moments waiting for the camera to focus in a new area of the field when taking shots last night.

[ebiggs1 · Accepted solution]

And it will continue that way if you keep listening to all the mishmash of suggestions. You need to go back to the basics. The SL1 can provide great photos but you need to set it up correctly. I will almost guarantee you AI-servo is one setting that is working against you as is using more than one focus point is a bad idea.

[Anonymous]

Perhaps the moderator can uncheck it for you.

When you tried it last night, was there a lot of light or was it fairly dark?

Is it possible to borrow another camera to try the lens on? That would tell if the lens is malfunctioning or if it is your camera. Since you stated that another lens works ok on your camera, I think your camera is ok.

[Britteny]

We took care of it for you! 🙂 

[ebiggs1]

Did you do the test? And did it pass or fail? If not reset, full 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. This will tell you if the camera/lens is working properly.

You have to go back to the beginning. You can't just make a bunch of guesses that folks also guess at. There might well be a problem with the lens. To be honest the Tamron is not the best lens on the market. But you have to systematically rule it out. You don't need another camera or another lens, just do the test as I outlined. If it passes the test you have set something wrong at the baseball game very likely.  Key to the test is the full reset and the initial settings. Follow closely.

[Bankesmom1]

I did do this test at home on Wednesday afternoon here at home.  I went outside and took several shots near and far.  All settings were where you told me to put them.  P, One Shot, WB, and ISO 200.  The shots around the house were good, but there were 3 different times when I tried to focus far away from where I was standing, the lens would not focus when the shutter release was pressed halfway.  That is when it typically focuses and then I take the picture.  And I had resent all settings to factory reset.  I researched that on You Tube and did it. 

[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]

BTW, a good idea is a new SD that is exactly the one recommended in your manual. Also don't buy a huge capacity size about 32 GB is good. Plus while you are at this make sure the battery is in good shape and fully charged. A faulty battery can cause this.

Get a top quality SD card that you buy at a good retailer. Amazon is not a good retailer unless you know for sure it is from Amazon and not a market place store. Sometimes lower price is an indication that the product is not the best.

[ebiggs1]

"I tried to focus far away from where I was standing, the lens would not focus when the shutter release was pressed halfway.  That is when it typically focuses and then I take the picture."

If it fired when you were in One shot mode, you were not really in One shot. One shot will not fire the camera if it can not achieve focus. If it simply would not change focus from near to far or vice versa it is most likely the lens. Tamron and other off brand lenses can and will do that sometimes. Usually a little jump start will fix it so quickly manually turn the focus ring on the lens closer to the subject.

Make sure you have a fully charged battery.