50L driving me mad

Picked up a new 50 1.2L on Friday and was very pleased with some close portraits I took around the house

Went out today to take some more portraits and the focus was several feet out all the time.

When I got home home I set up my test kit and adjusted the MFA until it was perfect. This was done with a Spyder lenscal target and my 5D2 tripod mounted. Again, everything is pretty good until the subject is more than about 6 feet away. One shot AF is quite bad and A1 servo is literally miles out. I don't mean missing the eyes and focussing on the nose I mean missing my kids altogether and hitting the chair in front of them!

Any ideas as to where I could be going wrong?

All shots were taken wide open so focus shift shouldn't be an issue

Can't post up the pics at the minute as I'm not on my Mac and don't think I can do it from my iPad.

How's the lighting for these 6+ feet shots? What camera to subject distance did you use for the MA tests?

Distant shots were in a sunny field. Did the MFA at about 8 feet so the more distant off shots were probably over 15 feet now I think about it

I will do some more accurate measurements later

sounds like my first copy 85L II, AF was all over the place when subject is over 10ft, returned it for 2nd copy and problem went away.

Not surprised. A lot o people have constant focus issues with the 50L. I'd ditch it and get an 85L II instead.

All shots wide open, 1.2 ? At this aperture the dof is paper thin and maybe causing the problem. I nrarely use mine below 2.8 as its very hard to achieve focus on subject.

People have had AF problems with this lens since forever. Well, at least since it was introduced.

I was interested in buying this lens, but decided to skip it and wait for a proper 50L II.

Seems that focus issues is part of the design in the current version.

Tonyz wrote in post #14309016
People have had AF problems with this lens since forever. Well, at least since it was introduced.

I was interested in buying this lens, but decided to skip it and wait for a proper 50L II.

Seems that focus issues is part of the design in the current version.

Or... or... or get the 85L II :P
I’m not that big of a fan of primes... I find a lot of times I reach for 70-200 IS II instead of 85L II

Already got the 85 1.2 II. If I was missing the focus by a few millimetres then it would definitely be down to me moving but the focus is feet out not even inches!

Sounds like a trip back to the shop

Best bet would probably be to return it, the AF is the main reason why I've been straying away from the 50L

Do you have any sample images ? Sounds like a bad copy to me. Mine is excellent! Takes time to get used to it.

iluxa007 wrote in post #14309051
Or... or... or get the 85L II :P
I’m not that big of a fan of primes... I find a lot of times I reach for 70-200 IS II instead of 85L II

85mm is too tight, 35mm is too wide, 50mm is just right!

On paper the 50L is my dream prime. Too bad it is so flawed.

Sunapollo wrote in post #14309104
Do you have any sample images ? Sounds like a bad copy to me. Mine is excellent! Takes time to get used to it.

Not working on my Mac so I can't upload anything at the minute but I am not talking about missing focus from the eye to the nose it is literally a foot or more out some of the time. The 85 has even thinner dof and hasn't given me the same trouble so I think it is probably a bad copy and will get it back to the shop tomorrow

Ho hum. I was loving some of the close up stuff I got out of it. Hopefully the replacement will be a good one

Actually, just borrowing a 50L myself, and used it for a car shoot i did an hour ago. Not at all impressed by this lens! It misses focus alot on my 1D3, the keeper-rate on the pics from this shoot is pretty low... And I borrowed to 50L to get some extraordinary shots, it seems like the lens let me down. Some of the exposures were just drop-dead out of focus. Had a bunch of shots where i focused on the grill of the car, and got the windshield in focus. Not cool!

I was worried id fall in love with this lens and convince myself that i had to buy one, seems like thats one less thing to worry about!

Do keep in mind, wide open at f/1.2, the dof is paper thin. Any movement on the camera will risk the accuracy of the AF.