Lens overexposing on own without camera settings changing.

[ri5671]

My Canon 50mm 1.2L is suddenly overexposing the next shots after I have metered correctly. I’m not changing any settings after the first. I tested my other lenses so I know it’s not the camera. Has anyone else had this happen? Should I just have it serviced? Is it going to cost a million $ to fix?

[ebiggs1]

"Should I just have it serviced?"

Yes!

"Is it going to cost a million $ to fix?"

A million, no, but ................?

[William_N]

Hi ri5671,

Welcome to the Canon Forum! So that the Community can help you better, we will need to know what model camera the lens is being used with. Any other details about your settings you'd like to give, such as the shooting mode, metering mode, drive mode, etc...  will only help the Community better understand your issue!

Also, do you remember anything in particular occurring with the lens right before the issue started?

If this is an urgent support need, please CLICK HERE to reach our friendly Technical Support Team by phone or email.

[ri5671]

I’m using it on a 6D at the moment. I also have a 5D MKlll which I haven’t used it on yet bc I don’t have it on hand. I shoot in manual, spot metering so nothing would change it in that respect. The first shot will look good, then subsequent shots are overexposed, then there might be another correct exposure thrown in there.
I switched between lenses and my other worked fine. I cleaned the contacts, not much else I can do.
I’ve used Canon for 20+ years, never had anything serviced!!!

[ebiggs1 · Accepted solution]

"I cleaned the contacts, not much else I can do."

Yeah, that's mostly just a feel good thing to do.  If you change lenses often, that alone will keep the contacts clean enough.

It is probably experiencing aperture blade, or blades, sticking and not closing down all the way.  Send it in for a C&C.

Check your settings. Did your exposure settings have a aperture several stops down from wide open (f1.2) ?

[Waddizzle]

Turn off spot metering and use the default, evaluative metering. Or, take a series of shots in Green [A] mode.

[ri5671]

I think you’re exactly right with the blades! I had a shoot today in the snow and 26 degrees and I took it with me, because it is, of course, my favorite lens. It worked fine! I think the cold was enough To get the blades moving correctly. I tried it a few times when I came home and it’s still working good, but we’ll see. I’m still sending it in, maybe it just won’t cost as much!

[ebiggs1]

"I’m still sending it in, maybe it just won’t cost as much!"

It is worth it if nothing more for the piece of mind knowing it is perfect. I have that same lens.  It is nothing short of fantastic.

I had the same lens back in the film FD lens era.  So it was not surprising I bought one for EOS.

[RobertTheFat]

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@ebiggs1 wrote:

"I’m still sending it in, maybe it just won’t cost as much!"

It is worth it if nothing more for the piece of mind knowing it is perfect. I have that same lens.  It is nothing short of fantastic.

I had the same lens back in the film FD lens era.  So it was not surprising I bought one for EOS.

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I don't have a dog in this hunt. I don't own, and probably don't need, that lens. But I strongly concur with Ernie, in that if you do own a lens like that, you're crazy if you don't try to keep it in good working order. You'd really be kicking yourself if you had it go bad again somewhere down the road, only to discover that Canon had stopped supporting that model.

[amfoto1]

Are you certain you're using fully manual exposure mode?

A lot of people say they are.... But then it turns out they're actually using Manual with Auto ISO, which basically turns Manual into another auto exposure mode. 

If that were the case... expecially if combined with Spot Metering... it could easily be the reason for variable exposures. 

Or, it could be the lens aperture....

In which case, cleaning the contacts might help.... carefully wipe them with a clean, lint free rag dampened with a couple drops of isopropyl (rubbing) alcohol.

Or, it might be that the lens needs servicing/repair.

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2) some other cameras, various lenses & accessories
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