EF-S 60mm: Funny problem :(

Hi All,

My EF-S 60mm is behaving erratically. My camera is set to Evaluative metering, and Aperture priority is selected. Low Light - manually opened up flash. This is the situation (note it doesn't always happen). When I try to focus, auto focus doesn't work. The green light blinks - indicating subject not locked? Setting aperture to as low as 2.8 doesn't help. Set lens to Manual Focus, shoot and you get a nice photo. Everything works. Sometimes, if I switch off the camera and switch on again, auto focus starts working perfectly well (same conditions). This happens only when light is low and not in daylight. Is it a problem with the lens or with the photographer. Note under the same conditions, kit lens works, so very low light should not be an issue here. Am I doing something wrong? Or is it time to visit that nearest Canon facility Any help appreciated.

just looks like there just isn't enough constrast for lens to lock onto. easiest thing to do is make sure af assist strobe isn't disabled in custom functions, or just get an external unit with af assist beam. green light in viewfinder is usually AE, while a red light is AF.

Thanks for your response basroil. That puts things in a different perspective. When this happens shutter speed shows as 00. So, it does have something to do with Exposure. Let me investigate further.

Try cleaning the contacts on your camera and the lens.

you mean av is at 00.. that means the lens is no longer recognized by the camera. if that is the case, either it is loose, it has dirty contacts, or the lens is broken.

Ooops, yes you are right. AV is at 00. Lens is good. I can get sharp pictures out of it anyday. I would clean the contacts. However, as I said this never happens when I am shooting outside - only in low light conditions. So, that may rule out dirty contacts though

dirty contacts happen for any reason. one few people remember is sweaty hands on contacts is pretty bad. salt+water+electricity​=funky stuff. check the contacts, and if anything keeps going wrong, it's probably faulty wiring which should be covered in the warrentee

Ok, the sensor was dirty. A little eraser cleaning seems to have done the trick and the lens is focussing now. Fingers crossed

Thanks basroil and In2Photos for your suggestion.