Quote Originally Posted by Sheiky


Quote Originally Posted by sirhc_1
Or does it still FF & BF even if you manual focus them??

That would be up to you -Short answer: no it won't. Longer answer...if it does, it's not the camera nor the lens


So, you're saying that lens-sepcific front- or back-focus AF issues will not be a factor if you manually focus. Ok, that makes sense if you're relying on your eyeball view of the subject, or you've changed out your focusing screen for one that provides more visual assistance (if possible on your body, which it's not on my 7D).


But, whatsirhc_1 originally asked was:



<div>


Quote Originally Posted by sirhc_1
Just want to know if the AF inaccuracies on both OEM &amp; third party lenses can be overcome by manually focusing the lens thru focus confirmation?

I'm not sure the answer there is the same, thatfront- or back-focus AF issues will have no effect. Since the focus confirmation (i.e. the green dot in the VF) 'knows' that correct focus has been manually achieved by (passively) using the data from AF system, it may be that any FF or BF issues would also affect focus confirmation, right? I don't know the answer - I suppose it depends on why FF or BF occurs with a particular lens, i.e. does it focus inaccurately,imprecisely, or both. (Note: those two terms have different meanings, see this graphical illustration or this wiki article). A lens that exhibits both noticeable FF and BF is imprecise (but may be accurate). AF Microadjustment corrects for inaccuracy, but not imprecision. It may also depend on how the misfocusing occurs, i.e. does the AF system 'know' the correct focus and the lens' motor just misses that mark, or is the AF system 'wrong' meaning focus confirmation would also be 'wrong'.


Thoughts, anyone?
</div>