August 02, 2014, 03:16:29 AM

Author Topic: Lens Parts for 50mm 1.8  (Read 384 times)

Gareththomasjones

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Lens Parts for 50mm 1.8
« on: April 28, 2014, 05:17:18 PM »
Hello, I hopefully will be getting a free canon 50mm 1.8 mk2 tomorrow. Unfortunately it is snapped in two. I don't know what piece is broken at the moment, all I know is the auto focus still works and the glass is intact. Im not sure about aperture at the moment, ill report back when I get it.

The question is, are parts readily available. And if so where.
PS I have a highly skilled satellite/electronic/computer wizard available to do the fixing!!

Gareth
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Lens Parts for 50mm 1.8
« on: April 28, 2014, 05:17:18 PM »

Mt Spokane Photography

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Re: Lens Parts for 50mm 1.8
« Reply #1 on: April 28, 2014, 05:32:54 PM »
You can contact Canon about the parts you need, chances are that a $70 refurb would be cheaper.  http://shop.usa.canon.com/shop/en/catalog/lenses-flashes/refurbished-lenses/ef-50mm-f-18-ii-refurbished
 
No matter how good a friend is at repairing electronics, the adjustments to the optics required to get it working to specification require special tools and software that talks to the lens and sends AF information to it, basically calibrating it for accurate autofocus is something that Canon controls very tightly.  There is a memory chip in every EF lens that contains the calibration information for that particular copy.
 
I'd sell it on ebay to someone who will use it for parts, and buy a refurb.

jdramirez

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Re: Lens Parts for 50mm 1.8
« Reply #2 on: April 28, 2014, 05:42:16 PM »
You can contact Canon about the parts you need, chances are that a $70 refurb would be cheaper.  http://shop.usa.canon.com/shop/en/catalog/lenses-flashes/refurbished-lenses/ef-50mm-f-18-ii-refurbished
 
No matter how good a friend is at repairing electronics, the adjustments to the optics required to get it working to specification require special tools and software that talks to the lens and sends AF information to it, basically calibrating it for accurate autofocus is something that Canon controls very tightly.  There is a memory chip in every EF lens that contains the calibration information for that particular copy.
 
I'd sell it on ebay to someone who will use it for parts, and buy a refurb.


Super glue is an option.  I wouldn't consider it for a more expensive lens, but the 50 f1.8 is just cheap enough that I wouldn't mind risking it.

What happened? I presume you dropped it.
Upgrade  path.->means the former was sold for the latter.

XS->60D->5d Mkiii:18-55->24-105L:75-300->55-250->70-300->70-200 f4L USM->70-200 f/2.8L USM->70-200 f/2.8L IS Mkii:50 f/1.8->50 f/1.4->100 f/2.8L->85mm f/1.8 USM->135L -> 8mm ->100L

Gareththomasjones

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Re: Lens Parts for 50mm 1.8
« Reply #3 on: April 28, 2014, 05:45:46 PM »
It was dropped by someone at my university photography society and they replaced it and were about to chuck this one away so I said I know someone that might fbe able to fix it. I'll post pictures when I get it.
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Gareththomasjones

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Re: Lens Parts for 50mm 1.8
« Reply #4 on: April 29, 2014, 05:27:44 PM »
Hi again, I have the lens. I have managed to get the two two pieces back together and they now work in MF. In AF it just hunts. Any ideas?
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Gareththomasjones

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Mt Spokane Photography

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Re: Lens Parts for 50mm 1.8
« Reply #6 on: April 30, 2014, 11:22:24 AM »
There are a couple of things, its likely that their is some internal damage, there are some wipers inside the lens that send position information to the lens, and if they were bent or not making contact, then the lens does not know what position its in.
 
The camera sends a command to the lens telling it where to focus something like move to focus at 5.2 ft.  The lens compares the position of the wiper on the resistor by measuring the resistance, and findsthe point where the internal data table says "X" resistance is 5.2 ft. (I've simplified the process to give the general idea).  If the circuitry cannot read the resistance due to dirt or a damaged part, it will hunt.
 
There are several other things that can make this happen, the flexprint that moves is also a frequent failure point.
 
The plastic case can be replaced for a few $$, but the lens glass will almost certainly be out of alignment, and AF accuracy will be off.

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Re: Lens Parts for 50mm 1.8
« Reply #6 on: April 30, 2014, 11:22:24 AM »