04-27-2016 10:29 AM - edited 04-27-2016 10:30 AM
I shot a Little League baseball game (8-year-olds). I had shifted the focus points group to the left so I could have focus on the batter, yet plenty of space in front of him for capturing the incoming ball. (and I use a quick tap on the DOF button to shift back to the center group after the hit).
A lot of the shots were overexposed so I re-read the manual again and found out why. Unless you're on "Evaluative" metering, the exposure areas are based upon the center of the frame, NOT where the focus is - AND - exposure is derived at the instant the shutter is tripped. Since the center of the frame was aimed at the dugout (where it was darker), the batter was overexposed.
So I learned another lesson! Yippee! (I wasn't using "Evaluative" because it was dusk, under the lights)
From what I read, I assigned the "*" button to AE. That allows me to position the center of the viewfinder over the subject then press & hold the “*” while I re-frame to position the left-shifted focus points group over the subject and half-press the shutter. Once I tap the DOF button to reposition the focus point(s) to center, I release the “*” and allow the shutter activity to establish the exposure. It works just fine in my living room – next games (4 of them) are on Saturday.
(Before you start in on me, I'm @ f/2.8 with my 70-200, and about 12-15 ft from the batter. My DOF is somewhat less than 6", so I can't lock focus/exposure and re-frame - the kids bob & weave too much.)
04-27-2016 11:17 AM
Well, it's not as though that behavior was any sort of secret. The primary alternative to "Evaluative" metering is called "Center-Weighted" for a reason.
Actually, I might even suspect that you were inadvertently using "Spot" metering before you switched. Even Center-Weighted metering should have noticed that the dark dugout was atypical of the scene.
04-27-2016 11:33 AM
One thing I think most new people believe is changing a focus point or metering mode will enable the camera to get multiple things in focus or multiple exposures in a single frame. Not matter how you focus or meter just one exact spot is perfect.
I suggest you select the main most important thing and concentrate on it. However you set the camera to accomplish that. Let the rest fall where it may.
I almost never take my camera off of single center focus point (and I have 45, 39 cross-point ). I do switch the metering modes a bit but center weighted is probably my most used.