Autofocus problems with new 50D

nobody

I just got a new 50D from Amazon last night, charged the battery that came with it for several hours, read some of the manual, then attempted to use the camera. I first started out with the 50 mm F/1.8 lens and attempted to shoot some test shots indoors in basic full auto mode. Made sure the lense was set to AF, etc. The autofocus appeared moved back and forth in a "hunt", but in this mode, the camera would never take a picture. I then switched to manual focus and found that in some instances it will take shots, but sometimes it simply opens the shutter without closing it. I repeated the process outdoors today using 3 different lenses with similar results, using both auto and semi-manual modes like AV.

If this camera is not defective and in need of immediate return, the only possible explanation I can think of is a weak or insufficiently charged battery (manual said it charges in 100 minutes and I gave it that long). I am going to put the battery back on the charger for a while and also talk so some experts at our local photo club meeting tonight and then give it another try. If it fails again, it's going back to Amazon ASAP and I'm ordering a replacement. Hopefully, they will pay for expediated shipping on the replacement if that happens. Any thoughts, suggestions, or similar experiences from others here? Thanks.

ziggy53

If you try to AF in dismal light the camera may have difficulty focusing. Since you said that the camera would start the exposure but not end the exposure it sounds like very low light conditions indeed and it sounds like the exposure was so long you gave up.

Try the camera again in more normal conditions and work back from there.

An external flash with a focus assist light can be a tremendous help in very low light.

Please do share any future images with us and make sure that the images include EXIF information so we can check the lighting conditions.

BTW, if you absolutely must attempt focus in extremely low light you need to use a lens like the EF 50mm, f1.2L USM and a 1D or 1Ds camera body. That combination will find focus in very poor lighting conditions.

jeffreaux2

Also....just in case....


Be sure you are not trying to focus on something closer than the minimum focus distance for the lens. Give it something with high contrast to focus on.....a blank white wall won't work.

Scott_Quier

nobody wrote:

I just got a new 50D from Amazon last night, charged the battery that came with it for several hours, read some of the manual, then attempted to use the camera. I first started out with the 50 mm F/1.8 lens and attempted to shoot some test shots indoors in basic full auto mode. Made sure the lense was set to AF, etc. The autofocus appeared moved back and forth in a "hunt", but in this mode, the camera would never take a picture. I then switched to manual focus and found that in some instances it will take shots, but sometimes it simply opens the shutter without closing it. I repeated the process outdoors today using 3 different lenses with similar results, using both auto and semi-manual modes like AV.

If this camera is not defective and in need of immediate return, the only possible explanation I can think of is a weak or insufficiently charged battery (manual said it charges in 100 minutes and I gave it that long). I am going to put the battery back on the charger for a while and also talk so some experts at our local photo club meeting tonight and then give it another try. If it fails again, it's going back to Amazon ASAP and I'm ordering a replacement. Hopefully, they will pay for expediated shipping on the replacement if that happens. Any thoughts, suggestions, or similar experiences from others here? Thanks.

The 50 f/1.8 is known to hunt a bit in dim light - no surprises there.

However, you are also having problems outside where light should not be an issue - so ...

Are you attempting to focus on an even toned surface or is there contrast in your scene? If the former, that could be a problem.

As to the battery, the time it takes to charge is variable ... can't really trust the 100 minutes claimed in the owner's manual. However, the charger does have a blinking light. As long as that light is blinking, the battery is not completely charged. When it goes steady, your battery is sufficiently charged, but I usually leave it in the charger for a bit longer.

A weak charge could account for the strange behaviour, especially that of the shutter. But, I've found that if there's enough charge in the battery for the camera to power up, then there's enough for an exposure - at least I've not yet experienced an exception to the is observation.

nobody

Thanks for the info. The verdict is pretty much in here -- the camera is defective and will soon be headed back. I tried letting the battery charge all night, just to be sure that wasn't the problem, as well as using 4 different lenses, including some shots in full light with the 70 - 200 mm f/4L. The camera does sometimes "hunt" for a focus when using auto focus, but it never acheives focus and refuses to take a shot in that mode. The only shots I've succeeded in taking are using manual focus. I even let a couple of pros at the camera club look at it last night and they pretty much agreed.

I have not read about this problem anywhere, so I suppose I'm just someone who ended up on the receiving end of some defect that occurs less than 1% of the time.

cmason

Just a thought: check your AF mode: if the camera is in AF Servo, you won't get a focus 'beep' nor will a focus pt light up. It should still shoot if you have focus though.