Center Weighted Average and outer focus points

Generally I prefer CWA with my 7D but I've never thought about the performance when using it with the outer focus points. This was never a problem with my rebel since I rarely used the outer points, but I have no problem using any of the focus points on the 7D. My question is what's the impact of using CWA with outer focus points, for example if my subject is far to the right or left of center. Does CWA shift the center and average based on my chosen focus point as the center?

No.

On the 7D all metering is based on the center of the viewfinder. The exception is when using evaluative metering where the camera is using the entire view but the algorithm gives the area around the selected AF point more importance in the calculations.

I don't have a 7D. My 1D3 has the custom function option to have Spot metering work off the chosen AF point (not Center metering), but I don't know if the 7D has that. Maybe someone who does know will see this and speak up, but in the meantime, read/re-read your manual to see what's there! The manual should have a list of the Custom Functions -- check for "Spot metering link to AF point". With the 1D3 that's C.Fn I-7.

Ah, I see others have spoken up while I was typing, and it seems that the 7D doesn't have that Spot metering capability, so my above post was just a 1D3 "perspective"...!

I planned on having a look at the manual when I get back home, unfortunately I'm at a client site and they block virtually every type of download so I can't grab an electronic copy right now.

krb wrote in post #13681651
On the 7D all metering is based on the center of the viewfinder. The exception is when using evaluative metering where the camera is using the entire view but the algorithm gives the area around the selected AF point more importance in the calculations.

So by that logic, I should probably switch to evaluative when I use the outer points since more weight would be given to the chosen focus point. This is the behavior that I assumed CWA would give me.

Sent a PM with the manual details for the various metering modes.

thanks Pete

Stone 13 wrote in post #13681686
So by that logic, I should probably switch to evaluative when I use the outer points since more weight would be given to the chosen focus point. This is the behavior that I assumed CWA would give me.

Depends on your shooting mode. If you're shooting in manual then you just use the center while setting exposure and then don't worry about it while focusing and shooting.

krb wrote in post #13681757
Depends on your shooting mode. If you're shooting in manual then you just use the center while setting exposure and then don't worry about it while focusing and shooting.

thanks for the advice Ken, I normally shoot manual when I have plenty of time and I know the subject isn't going anywhere, even though I know what I'm doing in manual mode, I'm still not fast enough when I have limited time to frame and shoot a moving subject, I know that will come with more time and practice. Alot of times I'm in AV mode and servo which is when I got the unexpected metering that led me to ask this question.

This is why I have my 7D set up so that the AF-On button is focus with the selected AF point while the * button is for AF with the center AF point. This way can just switch to Av and use the * button to focus when time is an issue.

Why not just meter/lock exposure with a half press, recompose, back button focus, shoot?

Only the 1 series meter from selected AF points.

Higgs Boson wrote in post #13682961
Why not just meter/lock exposure with a half press, recompose, back button focus, shoot?

I'm thinking about changing my style to exclusive back button focusing. I'd started doing it a year or so ago but I didn't stick with it long enough to make it a habit. This is another reason for going back to it.