Auto Focus Not Working

I see your camera has a focus area. If you have a subject with enough contrasting parts in this area, the focusing should work fine.
You must know that not every subject can be focused on as quick or as good as you would like. If there are little contrasting lines in the subject, or when it is getting dark or there are dark and light parts in the focus area, that don't belong together, every camera can have problems to focus correct. Changing the ISO settings won't change anything for the auto focus.
But special when you try to shoot in almost dark places, you camera will have lots of work to focus and in most cases it won't work at all.

You could try to place an object with light and dark lines, on the same distance as the object you want to picture. Then by pressing the shutter half, when focusing on the object with much contrast, you can look if the camera can focus. If it is in focus, keep the shutter pressed half way down, while moving to the object you want to shoot a picture of. Once you have every thing in the frame as you want it, press the shutter complete.

Hello,

Please remove the battery and and then insert it again and test to automatically reset the setting.

melnavz

So the problem here can be many things.

1. Either the camera is not focusing well
2. the lens is not clean
3. there is condensation inside the camera

is it possible if u post an image taken with the camera itself. also try checking if the camera has a master reset just in case u have set something that caused the auto focus to get disabled. like this you will reset the camera and get the auto focus back working.
the iso level will only control the lighting in your camera, so it will enable you to take pictures in darker areas when the iso goes higher. if your camera does not let you control the iso its probably set on auto.
regards

Try resetting your camera back to factory defaults. Press the MENU button, select the middle tools tab and scroll down to RESET ALL. Press SET, select OK and press SET. Hope this helps.

there is couple of possibilities like wise when you zoom lens manualy and can you heard the hard noise then could be AF unit itself faulty. AF unit gear is gone.
could be AF shaft broken thats why not focusing
could be AF Flex broken thats why not focusing
for that please bring to canon service center

Try setting the camera to M manual focus and manually focusing on the subject. Some combination of focus size and focus type may not focus unless the sensor sees a subject and is in focus. So if the sensor cannot see and know it is in focus it will not fire. If you subject is not moving then focusing in manual will ensure the subject is in focus and the camera can shoot.

If you set the camera on "manual", it assumes you focused manually and allows you to press the shutter without having to stop half-way. Check your settings.

If it's under warranty, use the warranty. It takes my D40x about a half second to focus at most. I keep my camera in a dust proof case when not in use. I've had it for 2 years, it still works fine.

AI should be focusing. You really can't change many settings when you are shooting in auto mode. Is the lens in AF mode?

I'm sure you have long since returned from vacation!

Hope this helps!

My first suggestion is to send it back if it is under warranty.

The grease probably got so thick, from the cold, that it caused too much resistance for the auto-focusing mechanism. You probably have damaged the focusing mechanism in the lens. You cannot repair this, yourself. I don't know how cold is too cold but it really shouldn't have done that.... Tamron makes cheap lenses. Try and exchange it for at least a Sigma.