I have gotten tons of traffic to my previous blog post about my experience with the Canon 24-105mm lens problem. Basically, if you get an Error 01 message on your camera and you’re shooting with a 24-105, it is the lens, not the camera. I now have two of these lenses that I travel with: one new one and the old one which has been serviced. It seems like there is no rhyme or reason to the failure, it happens spontaneously and without notice, leaving whoever is shooting with that lens stranded. Canon has been very responsive to all of my problems – their CPS program is top notch. But it is indeed irritating to be on location and have equipment failure. On the other hand, I’ve had my fair share of purely mechanical failures before the popularity of shooting digital. My Hasselblad has fallen apart more times than I care to think, but because it’s mechanical and the problem is usually due to normal wear and tear that a professional would bestow upon heavily used equipment. This issue with the Canon 24-105mm lens is vexing, but I haven’t been notified of a recall. If I am, I’ll be sure to post about it and if I get any insight from Canon as to why this problem seems so prevalent, I will share whatever information I can. All I can say is that if you are going to get the lens repaired, send the body in to a Canon Factory Service Center with it and have everything inspected and cleaned at the same time. If you are a serious pro shooter, apply for the CPS program. The technicians know their stuff and do a great job with repairs and cleaning. Happy Shooting!
Commercial, Editorial and Travel Photographer Susan Seubert 
Hi Susan. Canon don’t acknowledge there is a problem with the diaphragm on the 24-105mm despite the hundreds of disgruntled customers that are all over the internet with the same problem. Where to go from here?
Regards, Graham McPherson
Hi I am having the same error code one with the 5d Mark II and the 28-300 Canon L series Lens. Is it the lens or the Camera?
@Rachel – you should send both the camera and the lens to Canon for testing. I would also test the lens on another 5d Mark II body.
Sent my 24-105 to Canon uk. They have a fixed charge of £104 no matter what is wrong with the 24-105mm lens.
I’ve just sent my 24-105 for repair for same issue. Just adding my voice to the legions who seem to be having this problem. Unfortunately, the lens malfunctioned while shooting my husband’s grandmother’s 100th birthday. Arrgh! (Luckily I had my 50mm 1.4 lens – but lost a lot of time trying to figure out the trouble with my 24-105.) Very frustrating.
Cost of repair will be about $140. No acknowledgement from the Canon rep that this is a common issue.
As I also had the issue with the mirror detaching in my 5d (which Canon did recall), I am seriously thinking of switching brands. I’ve been loyal to Canon, but it seems like I’ve sunk thousands of dollars into a shoddy product.
I experienced the same problem today with the 24-105 attached on my 5d mkii. After googling around to see if it’s the lens or the body I confirmed it’s the lens. I was even able to reproduce the problem by attaching the 24-105 on my 7d and zoom in zoom out several times – albeit gently; eventually the 7d threw out an err 1 notification.
It seems there’s a cable inside the 24-105 that streches when zooming out and after some time becomes faulty. Will send the lens for repair.
Thanks for your post it was very useful.
Just came back from Kurdistan and experienced the very same problem with my Canon 5D mark II and the 24-105mm. Alternative if you’re on the road, switch to livescreen mode and shoot manual focus. Hope that helps, Swiss Nomad
Thank you for this great tip! Often times camera/lens failure happens in remote places, so this is a great temporary solution if you’re out in the field. Thank you for sharing!