Aperture Won't Close

cfgndhfkgjkf

It could be the aperture blades, or some electrical connection, or... who knows, but unless you are really handy and don't mind disassembling and reassembling a lens, Canon service is probably the best way to go. You covered the easy things and the next steps are most likely inside the lens.

.

notastockpikr wrote in post #18842605
.
Try cleaning the contacts on the lens. This is usually the first thing to try before sending the lens in for service.
.

.
Ha ha! . . Was this posted as a joke, or did you just not read the OP's post before responding?
.

john crossley wrote in post #18842442
I have a Canon 24-70 f2.8L lens and the aperture will not close. Shooting at f2.8 the lens works perfectly, but as soon as I try to use a smaller aperture I get an error message (Err 01 Communications between the camera and lens is faulty. Clean the lens contacts.) Cleaning the contacts makes no difference and using the lens on a different body has the same result. So I can only conclude that there is a problem with the aperture blades.

.

A relatively common cause of this behavior is a failure of the ribbon cable. A few years back it was reported to be about a $200 repair by Canon. If you feel adventurous, you can find some online step by step procedures for disassembly and you can get a ribbon cable on eBay for about $30.

If they're just stuck, you could always try poking the depth-of-field button a bit to try & unstick them, otherwise I suspect you're looking at a Canon repair...

john crossley wrote in post #18842789
Thanks for the replies.

As I said previously I think it is the actual aperture blades that are damaged as the lens works as it should when shooting at f2.8.

Because it only works at f/2.8 is a symptom of the ribbon cable problem, not something that rules it out. See the thread at https://community.usa.​canon.com …problem-again/td-p/247031. Multiple people report the issue, some have had it on several occasions with the same lens, and a common sympton is the lens only works at 2.8.

There can be other issues, a bad PCB board, bad USM motor, etc. and I think even some of them cause the lens to only work at 2.8.

John from PA wrote in post #18842879
Because it only works at f/2.8 is a symptom of the ribbon cable problem not something that rules it out.

.
Exactly right. If the aperture blades won't move, then it's probably a bad ribbon cable, because that's the thing that makes them move.

If, on a bicycle, the wheel won't turn when I crank the pedals, then it is probably not the wheel itself that is broken, but rather the chain that causes the wheel to spin. . Or if the wheels on my car won't spin when I power the engine and put it in gear, then there obviously isn't anything wrong with the wheels or the tires - rather, there is a problem with the drivetrain. . This here with the ribbon cable and the aperture blades is the same concept.

.

I would think that if it's working at f/2.8, then the PCBs and pins are functioning as the lens is reporting back to the body that it's at f/2.8, thus, no ERR01. I'm still guessing ribbon cable or motor.

john crossley wrote in post #18842789
Thanks for the replies.

As I said previously I think it is the actual aperture blades that are damaged as the lens works as it should when shooting at f2.8.

As for repairing the lens myself, I am very confident in stripping the lens down, it's putting it back together that's the hard bit.

Getting to the aperture assembly will require complete disassembly.
If you buy just the ribbon, soldering will be required to remove and replace it.
A replacement aperture assembly with the ribbon already attached is much easier.

I had the iris replaced by Canon in my old 35F2. I wouldn’t try this myself with a very expensive lens. The cost was $109 plus shipping and worth it. I have no idea what the cost would be for the 24-70, but Canon can provide an estimate.

gjl711 wrote in post #18842926
I would think that if it's working at f/2.8, then the PCBs and pins are functioning as the lens is reporting back to the body that it's at f/2.8, thus, no ERR01. I'm still guessing ribbon cable or motor.

But the OP reports an error...

john crossley wrote in post #18842442
I have a Canon 24-70 f2.8L lens and the aperture will not close. Shooting at f2.8 the lens works perfectly, but as soon as I try to use a smaller aperture I get an error message (Err 01 Communications between the camera and lens is faulty. C

Worthwhile thread, comments especially, at http://marcschultz.com …e-death-of-the-diaphragm/. Somewhat different than OP's problem, in that the lens goes to minimum aperture, not wide open.

By the way, which version of this lens do you have? It apparently was released in 2002. If you have the original, it likely isn't repairable, at least in the eyes of Canon.

John from PA wrote in post #18842963
But the OP reports an error...

At any aperture past f/2.8. Shooting at 2.8 works fine. That's why I think that the electronics are working and the pins are connected. It's past f/2.8 that causes errors.

Same problem on my 24-105L mk 1.
Error 01. Tried cleaning contacts but still no good, so sent to Canon repair centre. They repaired the lens by replacing the aperture unit, and also done a clean. Cost was £211 including insured delivery both ways and took one week.

....ooops, not enough coffee that day.