‘error 99’ read the message on the back of the Canon 400D display (LCD monitor) when using the Canon EFS 17-85mm lens. This camera worked fine with other lenses so we concluded that it was the 17-85mm that had the problem.
Advice given on camera display: Turn power switch off and on again or re-install the battery. That didn’t work – despite the odd single shot working. Online search suggestion of using rubber on contacts didn’t solve the problem either.
Rather than adding to the lists of this same problem on forums, I directed my query for help closer to home – to my other half (OH). His online searching took us to a blog by Roman Paulov ‘Canon 99 error or how to disassemble Canon 17-85 IS USM and replace diaphragm unit’ with excellent step-by-step photographs which gave OH confidence to attempt this with my lens!
Please wait just a moment, should you be considering quickly clicking across to Roman’s blog with a view to trying this yourself. I do understand your hurry 🙂 However, I’d like to highlight Roman’s words of warning under his list of tools required to disassemble this lens:
”This is not a official Canon guide. All responsibility is on you. Remember: after disassembling the device, you lose your warranty! “
Below you can see a few phone shots which were taken during the process of the disassembly and reassembly of my camera lens – quickly and nervously on my part! If you want to see proof that my lens actually worked again you’ll see that on my previous garden blog on a visit to Edinburgh Botanics 🙂
After reassembly: lens in and extended.
During disassembly: parts laid out numbered in disassembled order.
(The reverse rebuild was not so easy – OH described it as like climbing a tree,
but not taking a note of where you’ll need to stand to climb back down)
The faulty diaphragm
OH suggests problem was metal fatigue at sharp bend of flexy orange ribbon.
(Purchased replacement from this ebay seller).
Lens partially reassembled.
Orange ribbon seen on LHS goes down through lens unit.
PH000, PH00 & PH0 screwdrivers used for the many tiny screws.
(purchased inexpensive Rolson 6-part-precision screwdriver set)
Centre fork not lined up making focusing not possible.
(shown above in correct position – took 3 rebuilds to figure what was wrong)
Binary weighted tracks.
Five metal fingers to left of number 24.
(OH likes to point out what he thinks are interesting parts to me :-0)
Good luck if you are thinking of giving this a go! I should probably add something of our experience here. After the first reassembly, OH found himself almost completely stripping my lens back again! He stripped it back to the inner part three times and other parts were stripped back twice more before he reassembled my lens to full working order again. Nerves all round there – this really isn’t a job for the faint-hearted!
One last thing to consider, as may be expected, OH got quicker and more confident each time he disassembled and reassembled my lens. However, stripping back and rebuilding so many times wasn’t good for our nerves or my lens. OH advised me that the percentage chance of my lens ever working again was being reduced each time! I am usually an optimist but in this situation I became a realist.
Thanks, Roman – your blog certainly helped us out and got my lens working again! Perhaps I should mention that sometimes the images don’t load and a small insert is given when following your link. Perhaps this is a popular page for loading 😉
Ah… but the biggest THANKS go to OH for finding Roman’s blog and being willing to test his nerves for a working camera lens that has had so much use during gardenwatching and garden visits. For OH, let’s hope this fix lasts now 😀
Finally, in the spirit of blog link equality, seeing as Roman has had a few links here, OH has definitely earned a couple too! OH is now blogging himself at LINEAR THOUGHTS. His most popular post is: Sky SR101 Broadband router review – hardware and software. OH was interested in how this router works and thought others might do too! It seems they do 😀
This post was published by Shirley for shirls gardenwatch in April 2014.