Focus peaking v. magnification

mimritty wrote:

Thanks for your replies.

It sounds like it may come down to a matter of choice and taste. So far my experience has been more like jeffharris' but I'll keep playing around with the focus peaking and see if I improve with practice. In the meantime, my fn button is set at magnification as that has been producing really good results.

Way to go,  I think if focus peaking is not working for you then you have not yet learned how to read it properly.  It uses the same contrast detect information that AF lenses might use and we don't get complaints much that AF lenses are not getting correct focus.  Of course AF on lenses is directed at certain points in the screen whilst focus peaking checks and highlights the whole area in focus to the point of actual depth of field.

Also by relying on contrast detect the focus peaking is maidservant to the contrast in the subject matter and also the resolving power of each lens.  AF contrast detect focus systems probably auto-compensate for this variable level of contrast to the point where it may even be lens specific.  But the focus peaking systems in a generic sense in camera do not.  This is more obvious in the Sony system which does not seem to be scaled at all.  In Sony parlance their system ranges from the ink-blot effect unmagnified with an almost always in focus wide to completely disappearing with a low-contrast telephot lens on magnified screen.  They throw in colors and various stength adjustments to try and allow their users to compensate (as does the Panasonic M4/3 version at least).  But in my opinion the Panasonic system makes a better fist of it than the Sony one.

Therefore if the lens does cover a significant depth of field the user has to be cautious and use the dof shown to figure out the true centre of focus (or magnify the screen) in the case of longer lenses then a magnified screen and some practical training and sensible thought process is very useful. Focus peaking will always show everything on the screen in focus to the point of the strength of the signal and the resolution capacity of the lens in use.  With some observation it can also give good judgement of the dof of the image in focus (hence indicating more than just the centre point of focus).  Focus peaking is just another very useful tool and used as it is meant to be used - with some experience and with intelligent thought.  Certainly not a fail safe cure all.  Practice improves judgement.