Finally, we have some illuminating commentary. My thanks go to theSuede.
My point about focus shift is that if it really is that critical, if it really is a dealbreaker, then don\'t use a lens that has such problems. You can\'t get everything you want--if the system isn\'t working for you, then find another way. The reason why I say it\'s overblown is not because nobody should ever find it problematic, but rather, because so many people blame missed focus on focus shift, when in fact there are many, many other potential (and likelier) causes of missed focus.
For example, one can miss focus because of:
1. Improper AF technique
2. AF miscalibration
3. AF system failure
4. Insufficient AF precision
5. Focusing screen misalignment
6. Improper MF technique
7. Failure to use split prism screen
8. Use of focus-and-recompose
9. Insufficient visual acuity
10. Subject or camera movement
11. Focus shift
just to name a few. I\'ve seen threads where people complain about the 50/1.2L and show sample images with missed focus on distant subjects at f/1.2, and then claim that this is due to focus shift. No, it missed focus because of some other reason. For the alt-lens crowd, I can appreciate that certain designs are prone to focus shift and that this is problematic. But not all lenses have it, and you\'re just going to have to make the tough choices like everyone else does and decide whether such issues are worth dealing with. Though some come very close, there is no such thing as a perfect lens.
Mar 14, 2011 at 12:52 AM
Previous versions of wickerprints's message #9401232 « Risk of focus shift issues in new 1.4/35? »
No, it missed focus because of some other reason. For the alt-lens crowd, I can appreciate that certain designs are prone to focus shift and that this is problematic. But not all lenses have it, and you\'re just going to have to make the tough choices like everyone else does and decide whether such issues are worth dealing with. Though some come very close, there is no such thing as a perfect lens.