Canon 100-400mm lens focus problem
in [Digital Cameras]
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From: Wally on 18 Dec 2009 21:58 My Canon 100-400mm lens is 7 days old. This morning while autofocusing on a bird, it lost focus, started hunting, and then stopped focusing. The focus was jammed at the minimum focus position. Manual focus wouldn't work either. The zoom was at 400mm, and it was on a 40D camera. The situation was remedied by zooming in to less than 350mm. Then it autofocused again for a moment, but then jammed again in the same position. Turning the camera on/off makes no difference. After about 20 minutes of tinkering with it, the lens resumed normal operation. But a few hours later it jammed again. Anybody else have this problem? Is there a remedy? The guy at the store where I bought it said to just keep using it till it always does it, because it can't be fixed if it is not acting up. But I think I will return the damn thing and let Canon deal with this intermittent problem. Wally
From: Ray Fischer on 18 Dec 2009 23:21 Wally <Wally(a)luxx.com> wrote: >My Canon 100-400mm lens is 7 days old. This morning while autofocusing >on a bird, it lost focus, started hunting, and then stopped focusing. >The focus was jammed at the minimum focus position. Manual focus >wouldn't work either. > >The zoom was at 400mm, and it was on a 40D camera. > >The situation was remedied by zooming in to less than 350mm. Then it >autofocused again for a moment, but then jammed again in the same >position. Turning the camera on/off makes no difference. > >After about 20 minutes of tinkering with it, the lens resumed normal >operation. But a few hours later it jammed again. > >Anybody else have this problem? Is there a remedy? Yep. Send it back to Canon or get a replacement. If you fiddle with it too much you may void the warranty. >The guy at the store where I bought it said to just keep using it till >it always does it, because it can't be fixed if it is not acting up. But then he's a salesdroid and it's his job to take your money and then make you go away. >But I think I will return the damn thing and let Canon deal with this >intermittent problem. That gets my vote. -- Ray Fischer rfischer(a)sonic.net
From: Fred McKenzie on 19 Dec 2009 01:33 In article <iqfoi5p7vc87905clnjv7m0aacu73edhuk(a)4ax.com>, Wally <Wally(a)luxx.com> wrote: > This morning while autofocusing > on a bird, it lost focus, started hunting, and then stopped focusing. > The focus was jammed at the minimum focus position. Manual focus > wouldn't work either. > > The zoom was at 400mm Wally- What do you mean when you say manual focus wouldn't work? Were you trying to use the camera's AF system to determine if focus had been achieved? Some AF systems have trouble with small f/stops, especially in low light. Even if your camera has an AF-assist light, the bird may have been beyond its range. Fred
From: Wally on 19 Dec 2009 01:45 On Sat, 19 Dec 2009 01:33:50 -0500, Fred McKenzie <fmmck(a)aol.com> wrote: >In article <iqfoi5p7vc87905clnjv7m0aacu73edhuk(a)4ax.com>, > Wally <Wally(a)luxx.com> wrote: > >> This morning while autofocusing >> on a bird, it lost focus, started hunting, and then stopped focusing. >> The focus was jammed at the minimum focus position. Manual focus >> wouldn't work either. >> >> The zoom was at 400mm > >Wally- > >What do you mean when you say manual focus wouldn't work? Were you >trying to use the camera's AF system to determine if focus had been >achieved? Some AF systems have trouble with small f/stops, especially >in low light. > >Even if your camera has an AF-assist light, the bird may have been >beyond its range. The lens was hunting, unable to focus. Then I noticed it wouldn't focus on anything, near or far. The focus had stopped at 1.8 meters, the minimum focus distance. I tried the manual focus ring and it would not shift the focus -- it stayed on 1.8m. (This is a continuous manual focus lens -- manual can be used at any time, even when on AF.) Then I changed the zoom and that released the stuck focus system, until it happened again. Wally
From: Lucas on 19 Dec 2009 04:35
"Wally" <Wally(a)luxx.com> schreef in bericht news:iqfoi5p7vc87905clnjv7m0aacu73edhuk(a)4ax.com... > My Canon 100-400mm lens is 7 days old. This morning while autofocusing > on a bird, it lost focus, started hunting, and then stopped focusing. > The focus was jammed at the minimum focus position. Manual focus > wouldn't work either. > > The zoom was at 400mm, and it was on a 40D camera. > > The situation was remedied by zooming in to less than 350mm. Then it > autofocused again for a moment, but then jammed again in the same > position. Turning the camera on/off makes no difference. > > After about 20 minutes of tinkering with it, the lens resumed normal > operation. But a few hours later it jammed again. > > Anybody else have this problem? Is there a remedy? > > The guy at the store where I bought it said to just keep using it till > it always does it, because it can't be fixed if it is not acting up. > But I think I will return the damn thing and let Canon deal with this > intermittent problem. > > Wally Did you try setting the AF-select switch to 6,5m and beyond? |