HI All,
I have just received my (2nd copy) Canon 24-70 f/2.8 mk II. Being a faithful CR follower and reading http://www.canonrumors.com/tech-articles/how-to-test-a-lens/ I begain from the top and followed ever step I could as best as I could. I also have Reikan Focal and ran through every testing option there was available. What I have found suprised me to the point I originally thought I had received the dreaded bad copy.
There is a definite focus shift on the 24-70 mk II. I have found that from f4 to f5.6 it starts to back focus severely -5 afma vs +3 afma for f2.8 to f4 and +3 afma f5.8 on.
I am surprised there is not more information already out there on this.
I Found this on a competing forum http://www.fredmiranda.com/forum/topic/1177402 very similar findings
I understand through research you can hold the DOF button down to get around this issue? But would that reduce effectiveness of the f2.8 cross focus points?
After a quick search it appears the Tamron 24-70 has a very similar focus shift issue.
http://www.lenstip.com/340.5-Lens_review-Tamron_SP_24-70_mm_f_2.8_Di_VC_USD_Chromatic_and_spherical_aberration.html
Does anyone have any advice? At this point I don't know what to do?
Thank you for your time.
I have just received my (2nd copy) Canon 24-70 f/2.8 mk II. Being a faithful CR follower and reading http://www.canonrumors.com/tech-articles/how-to-test-a-lens/ I begain from the top and followed ever step I could as best as I could. I also have Reikan Focal and ran through every testing option there was available. What I have found suprised me to the point I originally thought I had received the dreaded bad copy.
There is a definite focus shift on the 24-70 mk II. I have found that from f4 to f5.6 it starts to back focus severely -5 afma vs +3 afma for f2.8 to f4 and +3 afma f5.8 on.
I am surprised there is not more information already out there on this.
I Found this on a competing forum http://www.fredmiranda.com/forum/topic/1177402 very similar findings
I understand through research you can hold the DOF button down to get around this issue? But would that reduce effectiveness of the f2.8 cross focus points?
After a quick search it appears the Tamron 24-70 has a very similar focus shift issue.
http://www.lenstip.com/340.5-Lens_review-Tamron_SP_24-70_mm_f_2.8_Di_VC_USD_Chromatic_and_spherical_aberration.html
Does anyone have any advice? At this point I don't know what to do?
Thank you for your time.