N2bnfunn wrote in post #17477330
Hello I have a 1DX with the latest firmware installed on it, the problem I am having is with one lens 24-70II, for some reason that lens will not auto focus correctly but all the other lens I use on that camera seen to work just fine.
At first I thought it was the lens itself, so I placed it on my 5DIII and it works and focuses just fine so it is not the lens.
Anyone else having problem with 24-70 II and their 1DX?
By "will not auto focus correctly" do you mean it hunts (and never locks), locks but almost always misses, or something else?
If it locks (in one shot AF mode) then put it on a tripod, point it at a fixed target (e.g. a newspaper) and see how it focusses through the viewfinder (phase AF) vs through Liveview (contrast AF). If it seems to focus ok in Liveview, then as others have suggested, it's likely to need some MFA.
I found the DotTune (http://www.fredmiranda.com/forum/topic/1187247) method to be pretty easy and not too time-consuming.
Note that if you can get them working together with MFA then there's likely to be nothing wrong with either the body or lens; every unit will be within a certain +/- tolerance. When you're unlucky enough to get both a body and lens that are towards the (same) acceptable end of the +/- scale then the combination can cause problems. The same lens on a different body (which will likely be somewhere else within that +/- tolerance range) could be fine; even though all the units in question are technically "fine".
As a simplistic example: if -20...20 is considered acceptable and you have a lens at -7 and body at +3, the result is -4 (OK). A +15 lens and a -5 body is +10, so also OK. A -9 lens and a -14 body is -23, so could be a problem at wide apertures. All those lenses and bodies though are within the "acceptable" -20...20 tolerance range on their own.