50 1.8 mkI disassembly photos

[igord]

<p>Seems to me only mkII is easy to find using google. Anyone could help? I would like to dissasebmly 50 mkI lens.</p>

[HenryUK]

<p>Here's some notes I wrote. Unfortunately I didn't take any pictures.</p>

<ol>

<li>I took the lens to pieces. It's very well made. The metal helicoid is mounted on<br />ball bearings.</li>

<li>Firstly you remove the front decorator ring by undoing the tiny grubscrew and<br />then turning it anti-clockwise to disconnect the bayonet fitting.</li>

<li>You then remove the focus scale window ring and manual focus ring.</li>

<li>Remove the metal mount at the back.</li>

<li>Unsolder the connections to the focus motor, iris, and AF/MF.</li>

<li>Unscrew the iris flex support bracket.</li>

<li>Remove the two screws at the ends of the arc form drive assembly and ease it<br />out. You have to be careful of the AF/MF switch tongue.</li>

<li>Remove the large screw near the anti-clockwise end of the AFD, and the lens<br />group can be extracted towards the front of the lens by rotating the helicoid.</li>

<li>After cleaning up the gears and reassembling, it focused smoothly and freely.</li>

<li>Unfortunately the autofocus hunted badly before locking on. I turned the preset<br />pot on the electronic flex through 3/8 turn clockwise and it behaved perfectly.</li>

</ol>

<p>I hope this is useful.</p>

<p>Henry</p>

[igord]

<p>Henry, thanks a lot!<br>

When I turn the front decorator ring counterclockwise nothing actually happens, I can't remove it.</p>

[HenryUK]

<p>It's a bayonet fitting. I found that you have to hold the lens barrel, turn the ring and then gently prise it off. It was a bit fiddly but it came off eventually.</p>

<p>Does the ring rotate relative to the barrel?</p>

<p>Henry</p>

[igord]

<p>Henry, only the ring rotates. I felt I could break it. Will try to do it one more time, gently.</p>

[igord]

<p>It doesn't work, I give up.</p>

[HenryUK]

<p>The EF 28 f/2.8 is very similar. Here's the illustrated parts catalog:<br>

http://www.f20c.com/stuff/canon/partslist/EF%2028%202.8%20(TYPE%201,%202).PDF<br>

I've also attached a cutaway picture of the EF 50 MkI.<br>

Sorry about the delay but I've been on business in the USA all week.</p>

<p>Henry</p><div></div>

[igord]

<p>Thanks Henry, will try again. I also was busy and didn't check the forum.</p>