Canon 50mm 1.2L HELP!!!

[shesees]

I was SUPER excited to upgrade in the 50mm department.  I got the Canon 50mm 1.2 L series just last week.  I ordered it brand new from Adorama.  I put it on my 5D Mark iii and tested it around the yard (with my chickens).  LOVED the quality!  I brought it out in the field with me to shoot an intimate wedding ceremony (20 guests).  It worked fine for the first 1200 or so shots.  Now every 5-6th image looks highly overexposed.  But the settings are exactly the same as the other images!  NO flash being used.  I haven't EVER experienced this with any of my other lenses (I have a lot).  Any advice?

ISO 1600  F2.8  1/320sec

[Peter]

May be sticky  blades. If that is the case the aperture will not close down to f/2.8 even if the camera reports it in Exif. My Fujifilm X100 had sticky aperture. Always f/2.

A way to check is to compare the depth of field between the pictures. If the depth of field changes it means the aperture isn't f/2.8.

[jrhoffman75]

Return it for a new one.

[shesees]

Yes, it's sort of like if I have to send it in for service, I'm getting a refurbished lens... that should cost less, rather than a pristine NEW lens!

[shesees]

Thank you Peter!  It does appear as if the background is blurred a bit more in the highly overexposed frame... which would definitely lead me to believe sticky blades could be the issue and it's shooting a stop or more wider.

[ebiggs1]

Hold on there partner!  Returning it won't fix a thing if it isn't the lens. It isn't common but certainly not impossible for a camera to miss exposure. I have had it happen and there is nothing wrong with the lens. Before you return it and get the same thing with a different lens, you need to try it on several other, different, cameras. A call to Canon support (1 (800) 652-2666) is also a better choice than returning without some testing. Do the testing first and make the call. You have plenty of time.

[jrhoffman75]

To me this sounds like more than a random missed exposure by the camera:  "It worked fine for the first 1200 or so shots.  Now every 5-6th image looks highly overexposed.  But the settings are exactly the same as the other images!"

Also sounds like she is 2+ weeks into the Adorama 30 day return window.

[kvbarkley]

Simple enough, were the exposure settings for the overexposed shots the same as for the well exposed shots?

[shesees]

settings are exatcly the same each and every time it happens.

[shesees]

Yes, I don't want to miss out on the window, so time is definitely of the essence and I'm not sure how it will go sending in to Canon.