mrsfotografie said:
jebrady03 said:
To avoid taking the filter off, indoors, in your own home, because you're fearful of damaging the front element is a bit paranoid, don't you think? Just take it off and retest. This will determine if your (mostly useless and possibly problematic) UV filter (you're using at night) is the problem.
I'm not fearful of damaging the front element in my home. Just lazy enough not to want the hassle of reassembing it all dust-free. In any case, I'm satisfied. There's no way I'm going to use this lens without a filter, so my current test results are good enough. I challenge you to test your copy and see if you can come up with the same results.
Since I have the same setup, 5D3, Sigma 35 1.4 and B&W MRC clear filter , I tried with a bright light coming from the side in a few different scenes last night.
I had no flare or anything that resembles a light leak. I am familiar with light leaks as I shoot Holgas and older film bodies. Sorry I was no help.
You did rule out the filter so the dust/removal/carefulness issue is moot. Since it's on two bodies it's not a leak imho.
The first course I would take is to update the lens firmware via the USB Sigma dock. If that does nothing send it in.