Fixing Canon EF 50mm f 1.8; need a tip.

[jesse_luo]

<p>Hey! I'm new to photo.net, so bear with me.</p>

<p>Right now, I'm trying to fix up a Canon EF 50mm f/1.8 MKII. I know, I know, it's a cheap lens, go buy another/upgrade, but...I really need to repair it. I can't afford to replace/go to a repair shop, and as far as I can see, there are no broken parts.</p>

<p>Anyways, the problem with the lens has to do with how the outer body connects with the inner body. There are two silver rings in the rim of the outer body. They're supposed to be glued in place (I think), but the top ring has come loose, I don't know the configuration at which I'm supposed to glue it. In operation, at a certain point of revolution, the focus ring will come loose, as the three extrusions on the surface of the inner body fall through the rings; this is the problem I'm trying to fix.</p>

<p>I've already successfully disassembled the lens...but my main problem is figuring out how the rings glue together, and how the outer and inner body stay connected while the focus ring moves.</p>

<p>If anyone could provide any tips, or even a photo of their working Canon EF's outer body's rings, I'd be much obliged.</p>

[sherman_peabody]

<p>Here's a video that may be helpful:<br>

<a href="

You could also Google on Canon 50mm 1.8 disassembly and see what turns up.</p>

 

[alan_bryant1]

<p>Here's a PDF with an exploded diagram of the lens - might be useful -</p>

<p>http://www.micro-tools.net/pdf/Canon/EF%2050%201.8%20II.pdf</p>

[jesse_luo]

<p>Thanks for the links, guys!<br>

I noticed in the YT movie linked, when the man was reassembling his 50mm, he had to twist his focus ring rather forcibly until he heard a click. Maybe that's how the upper and lower pieces hold together?</p>

[orly_andico]

<p>It's a snap fit. The outer and inner rings are held together by a spring-loaded metal ring. You have to distort that ring just enough so it snaps into place. But.. distort it too much and it will get out-of-round, making the focus grate at certain parts of the rotation.</p>

<p>I destroyed a 350D body by mounting a 50mm lens I had "repaired" onto it.. (some electrical short inside the lens fried the body). So think several times before trying this.. you might end up spending more than you expect. I know I did..</p>

[geoff_doane]

<p><em>I destroyed a 350D body by mounting a 50mm lens I had "repaired" onto it.. (some electrical short inside the lens fried the body). So think several times before trying this.. you might end up spending more than you expect. I know I did.</em><br>

<em> </em><br>

Hmm, I knew I was hanging onto those old EOS film bodies for<em> something.</em></p>