Originally posted by Igilligan This is a good thread for a question I have pondered...
When someone is asking about a AF macro lens to also be used as a portrait lens. I often see it mentioned that someone would chose the Pentax 100 because of it's"Quick Shift AF" like LeDave did here and many others do in other threads.
To me this is not really something I would use as a macro feature since I tend to MF and/or slightly move the camera to achieve focus on macro shots. And I just don't see quick shift AF being all that helpful for portraits when you are relying on AF.
It seems to me the "Focus Limiter" switch on the Tamron would be more useful in an AF macro lens that is going to double as a portrait lens. Sense you dont want the lens cycling thru the entire range every time your re compose a portrait shot.
Am I off base with this thinking?
Is 'quick shift' more important than 'focus limiting' on an Auto Focus Macro lens?
PS I would love the Voigt - 125mm! Or the siggy 180mm
Yes to your question...
I shoot quite a bit of macro, using both the FA and DFA 50mm and 100mm macros. From a practical and usability perspective, Quick Shift is by far more useful than the focus limiter. In a macro lens, the focus throw from minimum focusing distance to infinity is pretty long and the focus limiter merely restricts the lens from hunting across the entire focus range if it can't lock focus while autofocusing. But it will still hunt, just less.
Now with a lens with Quick Shift, one only needs the camera to attain focus and the photographer can then fine tune manually. This is far, far quicker than focusing macro entirely manually especially with skittish subjects like for example a dragonfly. With QS, the camera can quickly lock focus in AF on say the wing or abdomen and you can fine tune to get the eyes into sharp focus. Try shooting manually alone and the dragonfly will probably be long gone as you try to get precise focus and compose in the viewfinder. QS works on macro subjects and it will work on people too.
Frankly I don't even rely on the focus limiter on my FA 100mm much, it's too much of a hassle to use. So I will probably let it go once the new DFA 100mm WR Macro comes out because the new lens has got all I want... QS, better build quality, WR, rounded aperture blades and if the optics is anything like the current DFA, good sharpness and snappier contrast. It has all the makings to be a winner both with macro and portraits.