Lens (28-70 f2.8 I) 01 error, not focusing, dark; live mode kind of fixes it, but error returns

bill9991 wrote:

I bought a used Canon 28-70 f2.8 Mark I just a few days ago. It worked well until today. The only thing potentially out of the ordinary was a subtle clicking sound sometimes when I zoomed in or out, but otherwise worked. I went to use the lens today and it isn't working properly and exhibited strange behavior. Live Mode on one body temporarily fixes things, but not permanently.

First, it does appear to be the lens because I am getting similar problems on both a 5D Mark II and a 60D, while another lens works fine on both of these bodies.

There are a few things going on:

1. The viewfinder itself tends to be darker than normal, but not black - think early evening vs. midday.
2. If I push on the aperture preview button, it changes the amount of light that comes into the viewfinder. If I push it repeatedly, sometimes more light will come in and sometimes less.
3. The autofocus usually does not work - it tries, but is very slow and isn't able to actually focus on anything. On occasion, it will lock onto something, but usually not.
4. If in manual focus mode, it will take a picture, but then immediately give a 01: lens communication error.
5. I am not sure if the aperture is stuck, but visually it doesn't appear to be changing much from f2.8 to f22. (I haven't played around much with this, but when I took two pictures in manual focus mode and in manual mode - one with f2.8 and one with f22, they looked to have similar bokeh and lighting).
6. I noticed that one of the four screws on the backside of the camera is missing. I replaced this with one of the other three to no effect.

I have tried rubbing the connectors on the lens with a t-shirt and it didn't help. I have also been trying various combinations of manual focus, autofocus, AV mode, manual mode, different f-stops, different focal lengths, but the error persists.

I next tried Live Mode on the 5D Mark II. It worked perfectly. I switched out of Live Mode and it also worked perfectly! What??? But then I put it on the 60D and the above issues returned. I put it on Live Mode on the 60D but it still didn't work. I returned to the 5D Mark II and it didn't work out of Live Mode, worked in Live Mode, and worked after that.

It is a very specific set of symptoms and very strange behavior with Live Mode. Does anybody know what is going on? Thank you very much!

I would check to see if the aperture is getting stuck intermediately.  Setting the aperture to F22 and press the DoF preview button many times, while looking through the front of the lens to see if the aperture blades are actually closing.  Alot of times, the camera will give you an Err01 message because the flex cable that controls the aperture becomes faulty.  Constantly stretching the cable when zooming in and out over time will wear out the flex cable.  Symptoms are a dark image (like you have found out).  It sometimes works in live view because the sensor itself is acquiring focus, while in normal viewfinder mode, a separate AF module does the work.  They are usually limited to minimum aperture to acquire focus.   I had the same issue with one of my zoom lenses.

if a screw is missing from the back, someone may have tried to repair it.  I would recommend trying to get a refund if possible.

Thank you. I have experimented more and have found the possible cause - that I was taking on and off the lens when the camera was not turned off. I haven't tested it a lot, but it seems to work like normal (after acquiring focus in live view) when I transfer lenses when the power is off. Would this make sense? Do you think there is a faulty cable?

bill9991 wrote:

Thank you. I have experimented more and have found the possible cause - that I was taking on and off the lens when the camera was not turned off. I haven't tested it a lot, but it seems to work like normal (after acquiring focus in live view) when I transfer lenses when the power is off. Would this make sense? Do you think there is a faulty cable?

Honestly, I don't know if that is the cause of the issue.  I have changed lenses a lot without turning off the power and had no issues.  If that is the case, I would clean the lens contacts, and be sure they are aligned properly.  I would also check the lens contacts on the camera body side, to see if the pins are getting stuck (they are spring loaded).

as far as i know, cod 01 means there is no communication between camera and lens. so the symptoms you are alluding to, i presume the contacts between lens and camera need to be thoroughly cleaned with alcohol and hopefully that will remedy the issue.

This is most likely an aperture problem. If you keep the aperture preview button pressed while going from f2.8 to smallest aperture (Live View turned off) the aperture should close gradually when you look into the lens from the front. You should try that at both zoom ends, it has to work at both ends. If it does not, it is very likely the aperture unit.

If you can't transfer a lens mount screw into the empty thread, the lens may have suffered drop damage and the thread broke out.

Worst case scenario I guess, yikes. However, repairs nowadays should be difficult anyway. The fixed barrel (YG9-0312) should be out of stock these days. The aperture could be fixable though.

Thank you for your comment. I acquired focus using live view and started at f2.8. I then held down the DOF preview button and increased the aperture to f22. The aperture closed as expected. I released the button and went down to f2.8. Nothing happened.

The lens mount screw hole seems to be stripped as well.

Thank you. I have tried cleaning the contacts with a cotton t-shirt as well as rubbing alcohol. Neither worked.

Thank you for your comment. I acquired focus using live view and started at f2.8. I then held down the DOF preview button and increased the aperture to f22. The aperture closed as expected. I released the button and went down to f2.8. Nothing happened. Or, actually, when I started to do this (hit the DOF button), the viewfinder goes much darker.

The lens mount screw hole seems to be stripped as well.

You are right - it worked for a little bit, but now the problems have returned. Live view mode doesn't fix the problems.

Well at 2.8 the aperture blades won't be visible at all since that is max open position. If you stop down to f11 and take pictures at 28 and 70mm, do you get an Error01?

Yes, at f11 it gives the 01 error at 28mm and 70mm. It actually still does take the photo, but gives the error each time.

Can you not return this obviously faulty lens?

Why not instead get a used Tamron 24-70 f2.8 G2 as was one of your original plans n.b. I have the G2 and also had the Canon 24-70 f2.8 L mark one which you had also contemplated. The mark one has a huge lens hood unlike the G2 and it has no IS whereas the G2 has 5 stops. Both are large and relatively heavy.

I'm not sure why you would have chosen 28-70 rather than 24-70 as that makes a big difference in how wide the latter can go.

Ok, that must be a problem in the aperture assembly that has to be checked out. If it is returnable, I would give it back, especially since the fixed tube is also damaged.

I have asked the seller if I can return it, but he has not replied.

Oh my goodness - I meant to write 24-70 f2.8. I apologize for that.

Thanks for the advice on the Tamron.

Given that the lens gives the 01 error after every single shot, I will need to get a replacement, but will need to save up for it unfortunately.