Aaron D wrote:
Interesting info. Can someone possibly explain to me the differences between partial and CW? They sound somewhat similar.
"Partial" is "spot" done very cheaply. It's a big spot. Technically, the falloff of sensitivity should be very sharp as the edge of the partial area, but it's not knife-edge sharp. Yet, it doesn't read all the way out to the edges of the frame.
Center-weighted actually reads the entire frame, but takes most of its data from the central portion.
but if the light changes, or the scene changes, wouldn't you want the image to be correctly exposed?
Besides, "exposed correctly" is to a large extent a subjective judgment
And yes, I agree with you, but if an image is drastically off either way, it can be very difficult to "pull" it back in post.
Luckily there are enough different ways to get images for all of us. If you want it to adjust during a burst then you can, if not, then you have options too. I don't know what is the best way, so if it works for you, then keep doing it.
RDKirk wrote:
"Partial" is "spot" done very cheaply. It's a big spot. Technically, the falloff of sensitivity should be very sharp as the edge of the partial area, but it's not knife-edge sharp. Yet, it doesn't read all the way out to the edges of the frame.
Center-weighted actually reads the entire frame, but takes most of its data from the central portion.
Thank you. So partial is similar to spot, only the "spot" is larger than in spot metering? Is partial then basically a combination of CW and spot? In that partial uses info from a large portion from center, like CW, and partial doesn't take info from the entire frame into account, like spot?
Spot 85%, Center 10%, Eval 5%. When doing field sports, used Center a lot more...but not shooting sports much anymore. Under strobes, handheld meter all the time. Mostly I want the face properly exposed...the rest is just background.
Aaron D wrote:
Thank you. So partial is similar to spot, only the "spot" is larger than in spot metering? Is partial then basically a combination of CW and spot? In that partial uses info from a large portion from center, like CW, and partial doesn't take info from the entire frame into account, like spot?
Err, yes. I think of Partial as an alternative to CW. Prefer the Partial results to CW actually, glad that Canon came up with the Partial pattern. Even though the name is odd, lazy spot may have been better
Thanks Kelly. From what I understand, partial doesn't cover an area as much as CW, but more than spot. I've never really played around with the different metering modes I have available. Mostly because I didn't really understand them. So I've stuck with using evaluative. I'll have to give partial a try now.
Aaron D wrote:
...From what I understand, partial doesn't cover an area as much as CW, but more than spot.
One way to look at it is that Partial is like Spot, only bigger. It doesn't consider the edges of the frame at all.
Center Weighted is like Evaluative, in that it looks at the whole frame, but it "weights" the readings from the middle of the frame (gives them more emphasis) compared to the readings from the periphery.
q Evaluative metering
This is a general-purpose metering mode suited
even for backlit subjects. The camera sets the
exposure automatically to suit the scene.
w Partial metering
Effective when the background is much brighter than the
subject due to backlighting, etc. The metering is weighted at
the center covering approx. 13.5% of the viewfinder area.
r Spot metering
This is for metering a specific spot of the subject or
scene. The metering is weighted at the center
covering approx. 3.8% of the viewfinder area.
e Center-weighted average metering
The metering is weighted at the center and then
averaged for the entire scene.
An option is to have Spot link to the chosen single AF point too...and with so many, I'm constantly moving the AF point and Spot follows...very cool. I also turn off expansion as that is nearly never what I want it do...the subject is the subject, not stuff near it.
I'd like to use modes other than evaluative, but usually I find here in sunny az any sort of weighting towards the center blows highlights like crazy. Of course the 5d2 may be different (haven't had it long), in that highlightrecovery is better than the 7d...but I'm not sure it's THAT much better
The downside of course with the 5d2 is the whole pushing shadows 'argument bait'. ..so it's a fine line I am having a tough time getting right, tbh.
BrianO wrote:
One way to look at it is that Partial is like Spot, only bigger. It doesn't consider the edges of the frame at all.
Center Weighted is like Evaluative, in that it looks at the whole frame, but it "weights" the readings from the middle of the frame (gives them more emphasis) compared to the readings from the periphery.
Center-weighted is like partial, only much bigger, and hence more prone to errors, which is why all the other metering patterns were developed. It's nothing at all like evaluative.
Center-weighted is a throwback to the 1960's, and Canon left it in the cameras for those old-timers who don't trust the new-fangled pattern metering, but never learned how to use spot metering.
molson wrote:
Center-weighted is like partial, only much bigger, and hence more prone to errors
Arguably, less prone, in that details of a different tonality will occupy less of the metering area. In practice, I will use it only if the middle area inside the oval (1 series) will average to 18% and does not contain too many largish details.
It's nothing at all like evaluative.
Agreed. Evaluative seeks to arrive at a "correct" exposure for the scene, while the others deliver an 18% one weighted according to some function over area. I think evaluative metering originated on the Minolta SRT-101 (in the 1960s, BTW), also as a weighted function. However, matrix metering on Nikon is a black box which "works when it works" and it seems Canon wants us to think of their evaluative metering like that too. You can use such a system two ways:
1. You have no time at all to spend on metering and can live with a 10% (or whatever) chance of missing it completely.
2. You will take the same types of shots all day and have developed by experience or formal experiment a table of exposure compensations to apply. At least one bird photographer has published a book with such a table in it. That table might be "muscle memory" for some.
I'd be curious to know from those of you who do use it in case (2) how much work it was to develop that table and whether you had to do it all over again when switching cameras.
EDIT - fixed typo which might cause formatting problems some time.
Center-weighted is like partial, only much bigger, and hence more prone to errors, which is why all the other metering patterns were developed. It's nothing at all like evaluative.
Center-weighted is a throwback to the 1960's, and Canon left it in the cameras for those old-timers who don't trust the new-fangled pattern metering, but never learned how to use spot metering.
Yes. On a purely point-and-shoot basis, evaluative will be closer to correct more often.
