For the first time, after using Canon equipment for nearly 20 years, I experienced a mechanical problem with a Canon lens.
I was on a location shoot and, while looking through the viewfinder of my camera, suddenly everything went black. I depressed the shutter and nothing happened. Auto focus wouldn’t work, the camera was locked up. All I could see was darkness in the viewfinder and, although the camera was still powered on, it was completely unresponsive.
At first I thought my camera had packed in. So I removed the lens and depressed the shutter again to see if my camera body had actually failed. Then, without the lens attached, the camera shutter at least fired. Then I thought, if the camera isn’t taking pictures when the lens is attached, then it might be something wrong with my camera settings. At that point it hadn’t occurred to me yet that something actually went wrong with the lens while I was shooting.
But then I held the lens itself up to the light to look through the lens and I discovered that the aperture blades of the diaphragm had closed down into just a tiny little hole. I could barely even see any light coming through the lens, which is not normal. That’s when I figured out I had a real problem and might not be able to continue the photo shoot that day.
But before completely giving up, I tried putting the lens back on the camera and switching it into manual focus, yet nothing changed with the diaphragm. It was still stuck in the same closed down position. I could at least fire the shutter though with the lens set to manual focus, but shutter speeds were way off and the camera showed an error message on the preview screen each time after I depressed the shutter. Of course it still wasn’t capturing any photos either.

As per the error message, I removed the lens again, cleaned the contacts on both the lens itself and the camera body using a micro fiber cloth, but still no change. So obviously it wasn’t a lens contacts issue.
The lens involved with this event was my Canon 24-70mm F/2.8 L, which is a lens I got new and have owned now for about 10 years. I hardly use it though in comparison to some of my many other Canon lenses. From the outside the lens it actually looks virtually brand new.

New Canon lenses (for the last 20 years or more) all have lens apertures that are controlled electronically by the camera body. So there is no way to manually adjust a diaphragm nowadays using the aperture setting ring on the lens like before. So a few days later I decided to take the lens over to the Canon service center to be checked.
While standing at the Canon service counter I met another gentleman who was holding the same Canon 24-70mm model lens in his hand. I asked him what kind of problem he was having with his lens and he explained that he just had to have the diaphragm changed on his after the lens stopped working. A few minutes later, after discussing the symptoms of my lens with the Canon service staff, we came to the conclusion that my lens was having the same problem as his.

Now what are the chances of two people bringing the same exact Canon lens model to Canon in Thailand to be repaired at the same exact moment? Apparently reasonably high with this lens model.
After some further discussions with the Canon service staff, they explained to me that this is a common problem with Canon lenses after 5-6 years of use. This came as a big surprise to me as I have never had any problems like this with any of my other Canon lenses, and some of my lenses are getting close to 20 years old already.
The fact that two people showed up at the Canon service center at the same exact time, with the same exact lens and same exact problem makes me curious if there is simply a design problem with this particular model of Canon lens. Or maybe it is just coincidence?

Canon’s staff also mentioned to me that the other popular Canon 24-105mm F/4 L lens often has this same problem too. I myself also have the Canon 24-105mm lens which I use very regularly (see here), and I have never had a problem with it at all. In fact, I probably use my 24-105mm lens 5 times as often as I do the 24-70mm lens. So it seems likely the diaphragm problem is more prevalent with this 24-70mm lens than the 24-105mm lens.
In Thailand this repair from Canon costs you around US$130 equivalent. In North America, Europe, and other countries Canon may charge more for this same repair. But they made the repair very quickly and the lens was ready for pickup in about 2 days, which is good.
Bear in mind that after manufacturing this lens for ten years, since 2002, that in 2012 Canon stopped production of this lens and replaced it with a 24-70mm F/2.8 L Mark II version of the same lens. The new model is lighter weight and has various optical improvements.
Perhaps this issue with the diaphragm failing is now less common on the newer model, but I regret I wouldn’t know. I think many photographers, like myself that have the older 24-70mm F/2.8 L model, probably have not upgraded to the newer model, which now sells for close to US$2,000. Canon also released a lower cost F/4 version of this 24-70mm L lens which sells for around US$1,000. The price of the new F/4 model is roughly the same price that the older F/2.8 model sold for when I purchased mine for around $1,000. So price has gone up a fair amount for this lens on the new Mark II version.
If you have had a similar occurrence with this particular Canon 24-70mm lens, or any another Canon lens model, then please kindly post your experiences below. I would be interested to hear about them.




















Sadly, I also join the growing ranks of folks who have broken 24-70mm lenses. After researching this problem and looking at the myriad of quoted costs Canon appear to be charging, I’m determined to have a go at fixing it myself. I’m lucky that I have an engineering background which hopefully will help. However, I have a question that I hope someone can help me with – Is the diaphragm assembly the same for the Mark one and Mark two lenses? I ask this as I can only find Mark two diaphragms, and mine is a Mark one. Thanks in anticipation of any help.
No, unfortunately, the diaphragm (aperture) assemblies for the Canon EF 24-70mm f/2.8L Mark I and Mark II lenses are not interchangeable. While they may appear similar and serve the same function, the internal design and mechanical layout of the Mark II lens is significantly different from the Mark I. The mounting points, ribbon cable connections and the mechanical dimensions often vary enough to make substitution impractical or impossible without modification, and even then, the electronic compatibility might still fail.
Thank you for your very quick response. Your reply has saved me hours of searching for technical data, plus the risk of spending money on an incompatible item. However, I will continue to search for a replacement Mark 1 part. thank you again for your help.
My 24-70 f2.8 mk ii had this same issue the other month and I took it to get repaired. It cost me $690 in Florida. After reading other persons estimates, I feel I got ripped off. The error first occurred when shooting an event, they started blasting fog machines, and a few minutes later the lens stopped working, giving error 01 message. Not sure if the fog machine caused it or if a coincidence. Leading up to this point, there were one or two random times a few months prior the message came up, but began working again just from reinserting battery or taking lens off and on. I am wondering if I should sell it now with it repaired already and get a different zoom lens, or if this problem could likely occur with other similar zoom lenses as well
This just happened to me. Same clean contacts error message. Same lack of light getting into lense. Unfortunately happened in the middle of an event and I didn’t have another lense with me. Never making that mistake again. I think I might try to fix it myself tbh. I’ve been watching a lot of videos and it’s familiar territory for me. I used to build iPhones for Apple. Not sure where to order the part from yet and will still get a quote from my camera place.
Mine was 13 years old when it happened to me. Canon repaired it and I have shot 25,000 actuations since then. Still going strong. Love this lens.
Purchased new in 2006. It costs $325 to repair the diaphragm.
I’ve got the Canon 24-70mm 2.8 L first version. Mine has started to make a clicking noise when zooming out from 70mm. Doing some research leads me to believe this is also a diaphragm issue. Canon no longer makes this repair nor stocks the diaphragm any longer. If I’m not able to source it from a shop that does lens repair, i’m out of luck. This is a bread an butter lens for me, so I’m likely to be shelling out the money for a replacement.
I just received my canon 24-70 2.8 ll USM back from Canon today. I also had the error code 1 which I tried repairing on my own following the directions from their site and technical service call. This fix was intermittent, it continued to give me the error code and no longer work. It cost me $322.45 which was labor and materials. When I received it today the explanation says that the internal component did not operate properly causing an error to be displayed, the diaphragm was replaced so it appears that even in version ll, you can have the same problem.
My camera just came up with 01 error message, every time I step the aperture down from 2.8. It will not do a depth of field preview either, when the DOF botton is pressed (it does not give an error in this case). I am using the 24-70mm 2.8L lens. Bought it in 2013 and rarely use it; probably has about 10,000 exposures.
I will take it to a Canon service center, to see how much it would cost to repair. Will update my post then.
I’ve owned mine for 12ish years but I’m not a professional and it doesn’t get constant use. It just broke down this year when I got a 6D Mark 2. As other stated, Canon won’t fix it. My local (Rhode Island) repair place quoted me a little over $400 to fix it.
Thanks for the article. My 24-70 has the same issue. Just happened today on a video shoot. I’ve had the lens since 2014. If I decide to get it repaired, I’ll report back with the cost.
Best wishes with it. It seems there may be an issue now in being able to find the needed replacement parts.
My 24-70 2.8 MkII has just gone with the same problem. I’m in Spain and it’s going to cost 200€ to fix, so doesn’t look like the new version has been rectified.
This just happened to me yesterday. This was my goto lens for work and family. Yesterday while shooting an engagement couple the lens made a funny noise like you described and got the same error message.
So I tried to call Canon today and see about getting it repaired just to find out they are no longer repairing the first gen.
So my options I guess is to buy the Mark II version or find someone to repair this one.
-S
Hi Scott. Sorry to hear that and that Canon is no longer repairing them. Hopefully spare parts are still available somewhere to be able to fix it. Otherwise perhaps you can sell it for a bit of money on somewhere like eBay as a “non-working” lens to someone else who may want it for parts.
I’m having the same exact problem with a 24-105… Apparently this is a design flaw that Canon doesn’t want to take accountability for…. I mean, look at all this profit they would be losing out on if they actually took responsibility lol
Still sitting with a dead lens here… im confused with the variety of parts available online- ali express and amazon have four-pin cables but I’ve seen some with more exotic pin locations along the cable termination so I’m holding off ordering for now. I will have to actually open up the lens and see what sort of connector I need before I actually purchase the part.
Same here. Unfortunately, I needed a replacement ASAP, so I purchased the MkII for $1600. Still wondering if I should invest the $300 to have it fixed and then resell it. I’ve had it for 10 years. It has been rock solid until now.
Same exact symptoms and message. Now I have an idea what needs to be replaced.
Thanks for posting this information. Best regards, Jeff in Oregon.
Your welcome Jeff. Glad the post was useful for you. Best wishes.
Same problem but I am lucky enough to still be able to use the lens in Av 2.8 mode. EF 24-70mm f2.8L USM bought new in 2006 and it had been my primary lens for a long time. It failed for the first time this year (2019). The aperture blades got stuck. I managed to get it back to 2.8 by zooming to 70mm and then toggling the DOFP button a few times. The problem still exists in the lens; it will lock up again on any f-stop smaller than 2.8. So what I do now is just use it in Av mode at 2.8. It’s basically a fixed aperture lens, but I have other lenses so I’m not going to spend $300+ to have this repaired.
It sounds like you got good use out of the lens for many years at least before the problem started.
Yes, when the diaphragm breaks normally the aperture blades get locked in the fully open position, which sounds like what has happened to your lens too.
I recently did a low light shoot with this lens shooting with a group of people where I was forced to shoot at F/2.8 for the entire shoot. For me I felt the results were just too soft at F/2.8 and I wouldn’t be able to make use of the lens with only that one aperture setting available.
Instead of fixing it you could consider buying the 24-70mm F/4 L version of the lens to replace it. A much more affordable lens and lighter weight.
My 24-70 just had this exact issue come up tonight.. I’m looking into replacing the aperture ring and cable myself since there are now many guides online.
Interesting. Please let us know how it goes. Where will you source the replacement parts for it?
I have experienced the same issue with the same lens. It happened last year while i was trying to photograph my kids and we finally just sent it into Canon in Costa Mesa, CA. Our estimate labor cost is $269 while the part costs $26.68. They’re waiting for our approval.
Canon Service Center in Newport News, VA “estimate” for replacement of power diaphragm for my EF 24-70mm f/2.8L is Labor $269.00, Parts $26.88 plus shipping and sales tax. Comments: I have watched the complete disassembly of this lens. Estimated time for experienced person to disassemble and reassemble, IMO, is under 1 hour – probably much less is needed to replace this one part. The labor charge seems outrageous. However, the lens has performed very well and has taken about 31,000 photos prior this failure. When I replace the lens I will remember this experience.
Thanks for sharing your experience. It’s a shame that they charge so much for labor there. I often have lenses cleaned here in Asia by Canon for around $30 and I assume a cleaning where they have to remove all of the lens elements is more labor-intensive than just changing that one part as who said. Another thing you can look into is the possibility of getting yourself a CPS card from Canon. That’s a Canon Professional Services card and if you have a certain amount of Canon equipment they will issue you one for free. You can read about the requirements for the card online and you may be able to apply for the card online as well. The main benefit of the card is that it often gives you a 30% discount on repair charges from Canon service centers. So if you’re able to get yourself a CPS card first then perhaps you can save yourself a bit of money on the repair. Best wishes with it.
my 24-70l 2.8 aperture blade stuck at f22 and getting err 01
That could also be a diaphragm issue perhaps. But you can try some trouble shooting to see. First try cleaning the lens contacts with a microfiber cloth. If that doesn’t fix it then try the lens on another Canon body. If the other Canon body gives you the same error message then the lens probably has an issue. Then I would suggest taking it in to a Canon service center to be checked.
Bought my 24-70 L in 2004. diaphram failed October 2017. just sent it back to Canon for repair. Should know price by this Friday 4 November 2017
I have similar problem with my 24-70 f/2.8L and Canon USA in Costa Mesa California replaced the diaphragm assembly for $244. I did not experience the lens failing completely instead I heard clicking sound when turning the zoom ring so I brought the the lens in. The problem was not the diaphragm assembly itself but it was the electronic cable (picture above) rubbing again the lens barrel when zooming. After years of zooming this cable became loose, the tech said if I didn’t take it in I would eventually experience lens failure.
I had the exact same error message with the exact same lens. I sent it to Canon repair and I just received an email saying that the diaphragm needs to be replaced…total cost is $312.18.
I am sorry to hear that Cristy and hope you get it back and in good working order again soon. Unfortunately it seems Canon in the USA charges a lot more for these repairs than they do in Asia.
I’ve had the 24-70mm f/2.8 since about 2002 and I had my first problem with it this morning. It sounds a lot like your problem in that I get Error 01 and the aperture is stopped down. I haven’t sent it in to Canon yet, but I expect the diagnosis to be the same as your lens’ diagnosis.
Thank you for adding your info Tony. At least you have an idea now what to expect and the possible cost. I hope it all turns out well, is an easy repair, and fast turn around. Best wishes.
I have the 24-70mm F/2.8 L Mark II, the diaphragm went after just 22 months ! Although nearly a year out of warranty, Canon fixed it free of charge.
Thanks for the info Kevin. Interesting to hear the diaphragm is still a problem even in the Mark II model of this lens and that it happened so soon after you purchased it. I am also very happy to hear though that yours was still under warranty and was replaced by Canon for free. Best wishes.
I have had the same problem with my 24 – 105 F4 l lens in March 2012 while in Patagonia Argentinia.Luckily I had other lenses and a Fuji X10 with me.Lens was purchased in September 2007.
I’ve had a similar problem with my 50D and a Sigma 80-300 macro. I will probably shoot a few frames then it goes down and I can’t see anything, very dark. Both getting old of course.