Too much analytical horsepower applied to too simple of a problem. Mounting a huge powerplant on a rowboat doesn't make it a speedboat. It just makes it an unwieldy rowboat—and one that was performing its intended function just fine using oars alone in the first place.
Light meter and EV scale works for me. Nice and simple. Like me.
I just use a light meter and if the battery fails then use sunny 16 rule.
I look at a scene as I approach it and think that looks like 1/125 at f8, so when I'm there I don't have to waste time with this sort of thing.
David! In your original post you presented 2 different things.
1. The first is similar to what was called APEX system which I didn't know about until I started to use the same thing like you did. By assigning a number value to aperture and shutter speed it does make it's easier to calculate the shutter speed and aperture from a light value. This has nothing to do with a meter. You can use a calculating wheel similar to that of many older exposure meter. And yes I do like to assign numerical values to aperture and shutter speeds like the way you do. While at first it takes time to remember them but I found that I could learn them by heart quickly.
2. The second part you assign a light value to a condition for example full sun EV15 etc.. This part replaces the meter but one can elect to use this or not. One can use a meter to get the EV reading off the meter. However, I am like Cliveh that when I look at the scene I tend to intutively thought of an exposure in term or shutter speed and aperture combination rather than an ev number. And thus may need to those back to EV number mentally if I need to.
dave -- your system is not all that much different from some of the old methods of calculating exposure used before guys invented light meters -- I've got some in my collection, small books that go at great detail into sun, subject, time of day, time of season, etc etc etc.
It all boils down to being aware of your film, your equipment and your surroundings ... if your system does this for you, then good on you, ignore those who say you over-complicate things. I personally like light meters but consider them advisory only -- final subject assessment is done in that greatest of all micro-processors, the human brain.
Thanks for describing this, David. Although I've read a lot about EVs and LVs, and have played with the APEX system, it's nice to hear someone's actual experiences with guesstimating light values and exposures.
So i have a question, what ISO?
It's an honest question, not flippant. It takes all three.
Time and aperture are used to make creative choices, time controls blur, aperture controls DOF.
ISO finishes the equation to get proper exposure.
Im trying to figure out why.