Originally posted by mhoule418 I recently aquired a SMC-Pentax-A-35-105mm-F3.5. When I mount it on my K-5ii (or other bodies), I am asked to provide the FL of the lens. I know this is related to Shake Reduction.
I always wonder which FL to enter. Should I enter the 35mm (min) or the 105mm (max) value or something in between?
I guess that if I plan to use it at the max spectrum most of the time, I should enter 105mm.
But since it's a zoom, you never know in advance what will be the target opportunity.
Is there any rules of thumb to follow?
I think, from the thoughtful way you have considered the problem and have framed your question, that, even ~without~ any further advice, you will end up with a workable solution just by yourself.
I will just add my own strategy, FWIW: I also use and like the A 35-105/3.5 (on a K-3), and what I now try to do, using that lens for the example -
1. As a generality, unless I know ahead of time that I am very highly likely to be using it primarily at one end of the FL range or the other, I set it (at bootup or from the menu) about 1/2-way in between.
2. I navigate thru the menu to the "Input Focal Length" (Record menu 3, I think) setting (even if I've already set the FL when the cam booted) to make sure that the Menu will open again to that setting right away (in case I need to change it in a hurry).
[Note 1 -- For #1, obviously if I know I am, say, going to be shooting portraits, then I might set the FL for greater than 1/2-way from 35 to 105, or if I know I am, say, going to be shooting scenics, then I might set it for less than 1/2-way from 35 to 105, etc...]
[Note 2 -- For #2, obviously I have to also have the setting for "Save Menu Location" (Custom menu 4, I think) turned on for it to work.]