autofocus issue t1i

[gwenyth_m]

<p>Question: it seems like my autofocusing is off. The lenses (all 3) are having trouble and zoom back and forth trying to focus on something. Then when I go to push the entire way down to snap, it tries to focus again. It’s like I have to focus and snap really fast. I have the camera set to al servo (t1i). Manual focusing seems to be fine. (my eyes are just terrible so I don’t always trust them for focusing.) Is this my camera trying to force me into all manual, or what! LOL. any help would be appreciated.</p>

[phule]

<p>A camera uses contrast to autofocus. If the subjects you are trying to photograph are in very low light or lack any discernible contrast, or if you are aiming into the sun causing lots of lens flare, the camera will not be able to focus or will struggle with trying to achieve focus.</p>

<p>There are a number of different solutions, and would depend on the subjects you're trying to capture and the lenses you have. </p>

<p>Can you please provide some more information? </p>

[gwenyth_m]

<p>I have the 18-55mm kit lens, the 55-250mm, and the 50mm. I have a flash up on the hot shoe which is on and set to e-ttl. I notice the most issues with the 50mm. Last night I attempted to take some pictures of some equipment, in my living room with the overhead light on and the flash on in manual mode( and av and auto because it was having such trouble focusing). Settings were around 1/250-1/1000s, f3.5- 5.0, and iso at 400 and then at auto iso. But this happens outside in the shade, indoors in low light, on sunny days facing away from the sun. etc. There are also times when the camera itself seems to lock and it won’t allow pictures to be taken until the unit is turned off and on. :/</p>

[jaydesi]

<p>AI Servo means the camera will continually focus; switch back to one shot and you'll likely be fine.</p>

[phule]

<p>Which flash do you have? Most Canon flash units will project a red light hash-mark to aid with focusing. I've come to rely on it for low-light situations. </p>

<p>If you're using the flash, you're will not be able to shoot at 1/250 or 1/1000. The maximum sync speed of the camera is 1/200 with the flash.</p>

<p>I think it is important to reduce the variables here. Go outside, mid-day, and pick a subject with a lot of contrast and set the camera to full Auto mode. If you can get the camera to autofocus and take a picture then the problem is likely with one (or more) of the settings you've selected in your other modes. </p>