Canon 20D Focus jumps HELP! PLZ

[Lesika]

hello!
i dont know how to fix my focus on 18-55mm lens. before when i focused on something in foreground and them moved camer little a side, it keeped focus on that something in foreground. but now when i do this, my focus jumps from one thing to enother, it start to focus on anything that's right at the center. when i attache 90-300mm lens it works right as it supose to wotk. but then when i attache 18-55 lens again, it starts to jump. can i fix it or i have to get a new 18-55 lens.

 

[ksmattfish]

Do you have it set to the right kind of AF? I only use manual focus, so I don't know the specifics, but I think the 20D has 3 types of AF, and 2 of them are continually refocusing as the subject moves or scene is recomposed. Read your manual, and make sure you have it set to the right AF mode.

 

[tempra]

Make sure it's on One Shot and not AI Focus or AI Servo. (press the AF/WB button and turn the top wheel I think) If you want to make sure of the focus point, easy way is to set it to the centre AF point, then focus and recompose whilst still pressing the shutter button halfway.