1D III Micro focus adjustment

I just calibrated 3 lenses (300mm f/2.8 IS, 85mm f/1.8, 50mm f/1.4) and all three were best at an adjustment of -3. Has anyone else had a similar experience? I thought they would all be slightly different.

Thanks for your help,

Rob

My MKIII had all lenses at + values, then after the last fix, for some reason, they all moved very close to zero, a couple + and I think just one was -.

If you have several lenses and they all lean a certain way on the camera, the camera probably is a bit out of whack and in the old days, you would have to send your body in with your lenses for Canon to make adjustments. Now you can just save all that time and effort by doing the adjustments yourself.

I just did some 3 hour test, dealing with the MA feature on 5D Mark II and 4 lenses I own and frankly, I think there was a moment where it reached a point where my eyes/mind were playing with me so... to be sure, I re-did the whole test again so you might wanna try agiain..... juuuust to be sure you have got things right and not messing it up.

But to ans your q, they all had diff values. BTW, FWIW, I went to Canon Singapore not too long ago to have my 50mm f/1.2 calibrated and they shared (a secret) that the factory setting for Canon lenses is actually to have them back focused a verrrryy weeee bit.

All of my lenses give different values, my 300 +3 and 500 +5 for example

Except my sigma 150mm macro, which needed +15!

I found the most reliable method was to focus on a flat chart or card and use an angled ruler to see where the focus lies. I use the lens align lite. This is very consistent and gives repeatable results which are borne out in real world images.

Do not forget that the DOF with lenses is about 1/3rd in front of the point of focus and 2/3rd behind. That is why the default focus is slightly at the back. With micro adjustment you can move it to where you like though.