Canon 28-80 2.8-4L Aperture Problem

[anand_sihra]

<p>Hello again. I have an EF 28-80 2.8-4L lens that I absolutely adore. However, this morning, I found that the lens's aperture won't stop down at all. I can put it in Av mode and try to stop it down to f/22, and it will take the picture, but the aperture won't close. If I try to shoot anything in Auto, I get an Error 01 most of the time. Also, DOF preview doesn't do anything either. Shooting on a 40D.<br>

I know that if autofocus goes on these lenses, then I'm SOL. But does anyone know what the potential problem could be, and if there's any chance of repair? Thanks in advance.</p>

[JosvanEekelen]

<p>I had the same problem a couple of weeks ago with the 24-105 f/4L. The aperture unit (blades + motor/electromagnets) was broken. Repair was approximately EUR 200 by an independant repairer. I hope the unit for your lens is still available or you have to search for such a lens with a broken AF motor and working aperture unit.</p>

[Marcus Ian]

<p>It certainly sounds like the aperture mechanism is faulty, but it could also be a connector or cable that is the source of the problem. You aren't going to know until you take it apart though. </p>

<p>Assuming that you can find replacement parts, or a donor lens (that can provide the part(s) you need), the repair should be pretty straight forward and executable by any half decent shop. Unfortunately I doubt that list will include Canon, though you should probably try to give them a call first. Even though they probably won't execute the repair, it is <em>possible</em> they have the parts.</p>

[ed_avis2]

<p>Here's a part list for the lens: http://f20c.com/stuff/canon/partslist/EF%2028-80%202.8-4.0L%20USM.pdf<br>

<br />From that document it appears that the electronic diaphragm is part number CY1-2303-000. While some older 'L' lenses share parts with a less expensive non-L counterpart, meaning a fairly cheap supply of donor lenses, it appears that this diaphragm is only used in the 28-80L. Searching for the part number finds somebody in Barcelona selling it for 265 euros, and that's it.</p>

<p>You might possibly find a 28-80L with a complementary fault (broken autofocus motor, or broken/misaligned lens elements) and buy that cheaply to get the working diaphragm. Or possibly repair the diaphragm unit rather than replace it, though I have no idea if that is remotely practical.</p>

[ed_avis2]

<p>When I talked to Canon UK the 28-80L was definitely non-repairable by them. They won't even attempt to take it apart since, if they accidentally make the problem worse, they don't have the parts or spare units to make it good. And that was a couple of years ago. I doubt other Canon service centres would be different.</p>

[anand_sihra]

Thank you everyone for your

responses. I talked to the local

camera repair shop, and he said

it could be a bad connection, a

bad diaphragm, or something with

the firmware. Either way, he said

I'm looking at $200-$300 to

repair it. Not too worried at the

moment, as I usually shoot wide

open with this particular lens,

but I will get it looked at in

the near future. Thanks again!

[JDMvW]

<p>Recent prices <em>actually paid</em> for these on eBay have been varied, from as low as $250US to a more common $400+, so a repair may be a good deal even at $200-300, unless you are a skilled eBay bidder.</p>

[anand_sihra]

<p>Mr. von Weinberg, if Brian (my local repair guy), can fix it, it's definitely worth it. I only paid $200 for it this year on Adorama, so I don't have a huge amount of money tied into it in the first place. The only thing holding me back is finances, just bought a truck for my machine shop so funds are low for the time being.</p>

[JosvanEekelen]

<p>For the 24-105 f/4L the part cost was EUR 57.50, labor cost was EUR142.50. These aperture units seem a good investment :-)</p>

[anand_sihra]

<p>Thank you again for all the help, but my problem seems to have become more complex. I seem to get the Error 01 code even in Av mode if I use One Shot or AI Focus modes. There's no error when I use AI Servo. Maybe just a cracked ribbon cable to the mount contacts?</p>

[golem_bngolem]

<p>` <br>

<br>

You did clean the lens's interface/communication contacts ? <br>

</p>

[anand_sihra]

<p>Golem, I did clean the contacts, first with an eraser, and then with rubbing alcohol. No change. Well, I dropped it off at the repair shop yesterday. I've heard good things about them, so let's hope they can work some magic.</p>