Lens problem need help!


#1
Hi, I have a Canon lens 28-105mm f/3.5-4.5 ultrasonic. When AF mode I hold the shuttle button to forces, the lens mechanism making noise. Ultrasonic lens should be quiet right?

Got fungus on top of lens, but not really serious.

Please advise if me, AF mechanism got problem.
If anyone willing to take a look would be better.
 

Octarine

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Jan 3, 2008
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#2
How close are you to your subject? All lenses have a minimum focus distance. If you get to that point, the AF will try to focus which can result in some noise when the focus hits the mechanical hard stop in the lens.
Get the fungus cleared soonest, pictures won't get any better with fungus and it could spread to camera and sensor.
 

#3
How close are you to your subject? All lenses have a minimum focus distance. If you get to that point, the AF will try to focus which can result in some noise when the focus hits the mechanical hard stop in the lens.
Get the fungus cleared soonest, pictures won't get any better with fungus and it could spread to camera and sensor.
Any recommendation where got cheap service? $50 or more?
 

fatigue

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#7
Thanks Shierwin and Skystrike :)

Hi Terence Ho,

Is the lens unable to lock focus during AF. If yes, The quick back and forth movement of the USM is causing it to squeak,
Usually, the repair would require the USM assembly to be replaced.
Bad news: this is an old lens, replacement parts may not be available

I have seen similar problems on "not so new Canon lenses", and most of the time, the root-cause is simply an oil leak to the lens sensor bar (This part gives feedback to the microprocessor on the actual movement of the USM)
An oil leak to this part will lead to microprocesor blindly driving the USM.

Good news: cleaning the sensor bar from oil usually works
 

Oct 26, 2007
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Ang Mo Kio
#8
Thanks Shierwin and Skystrike :)

Hi Terence Ho,

Is the lens unable to lock focus during AF. If yes, The quick back and forth movement of the USM is causing it to squeak,
Usually, the repair would require the USM assembly to be replaced.
Bad news: this is an old lens, replacement parts may not be available

I have seen similar problems on "not so new Canon lenses", and most of the time, the root-cause is simply an oil leak to the lens sensor bar (This part gives feedback to the microprocessor on the actual movement of the USM)
An oil leak to this part will lead to microprocesor blindly driving the USM.

Good news: cleaning the sensor bar from oil usually works
Hi, Can I ask you?
I got a Tamron 28-300mm tele lens. Every photo I shoot the camera will show me an error. I forget what is the error but the photo was took. I just need to press another time shutter then the error gone so I can continue shoot the next photo. Sometime have to on off the camera.
This only happened when using this lens.
 

fatigue

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Sep 26, 2005
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#9
Hi, Can I ask you?
I got a Tamron 28-300mm tele lens. Every photo I shoot the camera will show me an error. I forget what is the error but the photo was took. I just need to press another time shutter then the error gone so I can continue shoot the next photo. Sometime have to on off the camera.
This only happened when using this lens.
I presume the lens is a Canon mount. If yes, then I suspect the flexible cable for aperture was partially damaged.
For Canon mount lens, the aperture is controlled fly-by-wire. Inside the lens, is a flexible cable that runs all the way from the main board (usually place near the mount), to the aperture mechanism located at the center . As you zoom in and out, the cable gets flexed and after some time, the cable gets damaged.
The cable consists of 2 sets of wires. One set of wires drives the aperture motor close/open. Another set of wires to monitor the aperture is fully open.
Most likely for your case, the wires that monitor the aperture were damaged.
So the aperture still works, and you can still take photos, but the processor couldn’t detect the aperture is fully open so it triggers an error display.
After the camera was turned OFF/ON, it “forgets” the error message sent by the lens.
So if the current state is clear, you can still shoot
But on a different level, errors (error history) are stored in camera’s EPROM for service diagnostics purposes.
In addition, flexible cable replacement is available online, so the lens can be fixed


Hope that helps

David
 

Oct 26, 2007
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Ang Mo Kio
#10
I presume the lens is a Canon mount. If yes, then I suspect the flexible cable for aperture was partially damaged.
For Canon mount lens, the aperture is controlled fly-by-wire. Inside the lens, is a flexible cable that runs all the way from the main board (usually place near the mount), to the aperture mechanism located at the center . As you zoom in and out, the cable gets flexed and after some time, the cable gets damaged.
The cable consists of 2 sets of wires. One set of wires drives the aperture motor close/open. Another set of wires to monitor the aperture is fully open.
Most likely for your case, the wires that monitor the aperture were damaged.
So the aperture still works, and you can still take photos, but the processor couldn’t detect the aperture is fully open so it triggers an error display.
After the camera was turned OFF/ON, it “forgets” the error message sent by the lens.
So if the current state is clear, you can still shoot
But on a different level, errors (error history) are stored in camera’s EPROM for service diagnostics purposes.
In addition, flexible cable replacement is available online, so the lens can be fixed


Hope that helps

David


Wow, same like what I suspected. When zoom in zoom out, I saw the cable inside got a path like abnormal but I can't confirm it.
Normally how much charge for this repair? Do you still providing repair service?

Thanks a lot, Pro David. ^_^
 

fatigue

Senior Member
Sep 26, 2005
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#11
Wow, same like what I suspected. When zoom in zoom out, I saw the cable inside got a path like abnormal but I can't confirm it.
Normally how much charge for this repair? Do you still providing repair service?

Thanks a lot, David. ^_^
Yes, I still do.

Thanks,
David
 

#12
Thanks David.

I'm thinking of replacing with Tamron AF 18-200mm F/3.5-6.3 lens. I have read review about this lens saying it's bad in low light. Any recommendation for this lens?
 

Octarine

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Jan 3, 2008
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#14
I'm thinking of replacing with Tamron AF 18-200mm F/3.5-6.3 lens. I have read review about this lens saying it's bad in low light. Any recommendation for this lens?
Please define "low light" and what you intend to do. Do not simply take over phrases from reviews without context.
 

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