Sigma 50mm color shift?

Hi Everyone!
I just received my 6th copy of Sigma 50mm lens (I've been lucky lol), and it came in with the usual AF issues. After a trip to Sigma back in NY, it came back better, requiring only a 13MA. However, the weird thing happens now: it color shifts, and underexposes images. I'm wondering if anyone ever experienced this behavior of "color shifting" resulting in yellowish/purplish combination of colors, as well as underexposed images by more than 2 stops! I'm now wondering if it can incorrectly pass meta information to the camera.
It's about to be sent back to NY again, and I'll supply photos later today. It's now officially my No1 hated lens ever!

are you shooting the same scene in a controlled environment and getting color shift?

c2thew wrote in post #14730398
are you shooting the same scene in a controlled environment and getting color shift?

Yes, and I've tried it with two bodies. "User error" is definitely eliminated.

Are you experiencing this both indoors and ourdoors? what is your "controlled environment" ?

Post an example.
By "colour shift", do you mean chromatic aberration or "purple fringing"?
Mention of yellow and purple suggests this to me.

post some pictures and we might be able to see what's wrong.

Never had this issue with my copy. My Sigma 50 1.4 is on the warm side and it stays consistetnly like that.

Curious, are you sending in the camera body with the lens to have it calibrated, or are you just returning the lens hoping the next one works better? My sigma 30mm is on the warmer side. 2 stops underexposed something is definitely wrong there. 7 is a lucky number... hope your next one works out.

any sample pictures?

I'll post the sample photos later tonight. It's a really weird effect. One shot may be overexposed (due to me using it at +1/3EV), the other can be very underexposed. And no, it's not CA. Sent the lens back to Sigma, and they're requesting the body, which I'm sending.

6th? good thing i ordered the canon....

Dang dude, seriously, 6 copies? I just received my first and last copy of the 50L and am thrilled. Creamy bokeh, superb sharpness, not a hint of color shift. I'm sure Sigma produces good lenses but 6 copies and still doubts? Dang it....

Roger