I have been re-reading Adams' book on the Negative which contains a chapter on t he Zone system. I am still quite a neophyte when it comes to the Zone system. In his chapter, there is an exposure record form (by Ted Orland) which has an "a djusted exposure" calculation to account for filter factor(s) and bellows extens ion/focal length.
My question is, when does one apply the entension/focal length factor? I have a 150mm lens and (for example) I focus on my subject with about 75mm of bellows d rawn. According to Adams' book I should compensate about .25 => (75^2)/(150^2). If my determined exposure is 1/15 (or .07) second, do I want to compute my fin al exposure (assume no filter is used) as .07 + (.07 *.25) (or .09 seconds total )?
Are there instances where one never wants to consider adding in this kind of exp osure compensation?
Thanks for answering what may be an easy question for many of you out there in z one system land...