Canon EF 24 - 105 mm F4.0L hit and miss

This lense is MY WORSE EXPERIENCE IN A WHOLE CANON LINE UP!
I just took it back and send it for repair.No, it is not flare it is FOCUSING IN A LOW LIGHT even with a speedlite attached ald fully operational TTL...

4 weeks no camera and lens... until they fix it I hope!

So, lens created with defect WILL ALWAYS BE WITH DEFECT.
L-series heh, better say Z-series lens...

Do you have other max f/4 aperature lenses that focus well on your camera body in the same lighting conditions? Also, what camera body are you using?

Is it standard procedure that Canon take your camera as well for lens repair?

I have Canon EF-S 10-22 no problem at all,I used to have EF 17-85 IS again good lens, I have 50mm 1.8 that is also great ,and Canon 20D as a body and 420 speedlite.

All these lenses perform WELL and people from Vistek did test with my 24-105 with a mixed results.When they used it the way I DID (same shutter speed same AF and all the rest) camera(lens) did not perform good.
Also sharpness off center was bad too...center was good.

So Bob here we go I always feel that you work for Canon somehow just kidding...

Well camera is stil under 1 year Canon warranty and lens is less than couple of months old(and out of box it was not working as it should) so if there is problem they can fix it on camera and lens too.I know people do have great expectations from an L glass and I am one of them too(after 1600$ can+tax)
Today on a wedding shoot, that is when my tolerance toward this lens has gone and make me MAD as hell.Also I have read here on the POTN that to get an optimum from your lens in terms of focusing performance on 20D, it should be an 1:2.8 glass.