07-16-2014, 05:43 PM
I did the mod on my EF-S 10-18 STM last night. Today I was playing around with my 5D Mk III and have discovered a slight problem........
For some odd reason it will not do Phase Detection AF on my 5D3. It works fine in LiveView using Contrast detection AF. When I mount the lens, the "One Shot" message on the top LCD goes to "M Focus". When I switch to LiveView or Video, it goes to "One Shot", but as soon as I go back to using the viewfinder, it goes back to "M Focus". Not only will it not AF, but there is also no green dot focus confirmation in MF mode.
I also have a 18-135 STM that does the same thing when mounted on my 5D3. Both lenses work perfectly on my SL1/100D and also my old EOS 630 film camera. The EF 40mm STM also works perfectly on my 5D3.
I went down to my local "Henry's" camera store and they were nice enough to let me try my modded 10-18 on one of their 5D3's and sure enough it behaved exactly the same way.
The 10-18 works with the 6D as reported by "Bright Colours", so I suspect this may have something to do with the advanced AF design of the 5D3. I also suspect that any other FF cameras with advanced AF (like the 1Dx) might also have the same problem with these APS-C STM lenses.
![[Image: 5D3_8586.jpg]](http://i2.photobucket.com/albums/y17/msowsun/photo%20stuff/Photo15/5D3_8586.jpg)
For some odd reason it will not do Phase Detection AF on my 5D3. It works fine in LiveView using Contrast detection AF. When I mount the lens, the "One Shot" message on the top LCD goes to "M Focus". When I switch to LiveView or Video, it goes to "One Shot", but as soon as I go back to using the viewfinder, it goes back to "M Focus". Not only will it not AF, but there is also no green dot focus confirmation in MF mode.
I also have a 18-135 STM that does the same thing when mounted on my 5D3. Both lenses work perfectly on my SL1/100D and also my old EOS 630 film camera. The EF 40mm STM also works perfectly on my 5D3.
I went down to my local "Henry's" camera store and they were nice enough to let me try my modded 10-18 on one of their 5D3's and sure enough it behaved exactly the same way.
The 10-18 works with the 6D as reported by "Bright Colours", so I suspect this may have something to do with the advanced AF design of the 5D3. I also suspect that any other FF cameras with advanced AF (like the 1Dx) might also have the same problem with these APS-C STM lenses.