the problem with your rigged example is real-world shooting doesn't allow spot metering off perfect grey 18% subjects. It demonstrates evaluative gave the best result overall 90% of the time.
like others covered, all automated exposure methods are flawed based on how they meter. including spot (more often than evaluative) unless you EC or use M along with spot.
regarding center weighted - changing exposure in a sequence is generally really a bad idea also and makes batch processing (small fixes) impossible).
wilt wrote:
The issue is not 'autoexposure' (which merely sets one or more parameters for you) but the suitability of any metering pattern along with whether or not the object/scene being metered correlates to the meter's fundamental asssumption of 'exposure for 18% gray'. Whether you use M or Av or Tv, all three can be equally wrong in the shot, because the METERING was based wrongly upon a wrong brightness.
In the case of the Evaluative example which I posted, while the camera was supposedly biased to the focus zone (on the 18% gray card), it also factored in the brightness of the adjacent metering zones which was NOT 18% tonality! ...Show more →
How many of you would LOVE a body, say similar to a T-90, or even a modern body, but lenses with controls like the later FD lenses - '1 touch zoom/focus', exposure ring etc - so that you could work manual that much easier? Basically a 'Manual' digital body? I know for one, I'd love say my t-90 with say a FF sensor stuck in the back
I use manual exposure mode a fair bit on discrete moving targets. Partial or spot metering helps me to determine proper aperture/ISO. (Shutter speed is normally dictated by the target motion, and not by exposure considerations.)
For scenic photography I do evaluative metering. If I wanna minimize the effects of extreme peripheral light or darkness, then I'll go for center weighted mode.
The difference between those two is usually subtle.
Environmental portraits I'll do using partial metering on person's face. If I get that right, the rest of the picture can be fixed in photoshop if required.
Sir_Loin wrote:
I was out and about today in the unseasonably warm weather for this time of year in Blighty and I was messing with different metering settings.
I found that I was getting more accurately exposed images with Centre-Weighted metering when there was a high dynamic range within the image. Evaluative metering tended to overexpose a little.
Which made me think, do other photographers change the metering under certain lighting conditions or just leave it set at one or the other all the time?
This was with both my 5D2 and 1D4 in case people were wondering what's this to do with Canon. ...Show more →
No "one" meter setting is going to get every single exposure done. That's part of the challenge...learning your equipment and how/why it works the way it does. Center Weighted as mentioned by others, is a throwback to those good old film days. 9 times out of 10 evaluative is the best choice for general shooting.
I have been using evaluative exclusively (except when shooting manual), but I will need to read carefully through this thread and re-evaluate that practice.
MrAdventure wrote:
No "one" meter setting is going to get every single exposure done. That's part of the challenge...learning your equipment and how/why it works the way it does. Center Weighted as mentioned by others, is a throwback to those good old film days. 9 times out of 10 evaluative is the best choice for general shooting.
Yes, I know Centre-Weighted goes back to film days, my good old Canon A-1 (among others) never really missed a beat with that method.
I know there's more metering options available, Spot, Partial etc for specific subjects and lighting conditions. But that isn't what I was asking. My question was to see if people still use CW or Evaluative as their go to method of exposure measurement.
I should have made it a bit clearer in my OP as to the specifics of my poll.
Evaluative for most part, but Spot if needed. In the same vein, only spot focus for me, other focus modes disabled. As for shooting, mostly Av, some times M depending on the needs for the shot.
I couldn't find anything in the manual about the camera not re-measuring the exposure during a burst in only CW. After looking through the metadata on some of my bursts, the 1D3 and 1D4 do re-measure the exposure for each frame even though it is a 10 fps burst. Doesn't seem to matter what metering mode you are in, it always will adjust the exposure. You can set it manual if you need the exposure to be locked for the entire burst.
For me it is either evaluative of spot, don't think I've used CW in awhile
When I'm outdoors with my 5dmk2 I can get very consistent exposures using evaluative. If I'm really concerned with bright backgrounds I'll use spot metering.
My 1dmk3 (not mk4) spot metering seems the only solution because IMO the 1dmk3 has pathetic metering for a prob body. From what I gather the 1dmk4 has improved metering drastically compared to the 1dmk3.
melcat wrote:
It would be nice if Canon bothered documenting what "evaluative" does.
...Is Canon's "evaluative" similar, but just using luminance? Or does it just choose one of a small number of sets of weights depending on criteria like "this looks like sky on top" and "this looks like it's backlit"? Does Canon seriously expect me to guess?
"Perhaps a better way of expressing the issue is as follows:
"1. Evaluative metering reads all segments of the metering sensor.
2. Primary emphasis is placed on the metering segment overlaying the active focusing point, or the center focusing point when the camera is set for manual focusing.
3. Secondary emphasis is placed on the metering segments directly adjacent to the primary metering segment.
4. Tertiary emphasis is placed on all other metering segments.
"Evaluative metering uses a variety of algorithms to determine if there is a need to apply exposure compensation to the reading obtained at the primary segment. The algorithms are proprietary and confidential for competitive reasons, but we know that they look at various factors including overall light level, backlighting, spotlighting, and an estimate of relative subject size, as revealed by a comparison of brightness values for each metering segment. They may look at other available data as well, but if so we're not sure exactly what that data may be or how it is used. We know that there are limits on the maximum possible range and gradation of exposure compensation steps that evaluative metering can apply, and we know that the specifications for these factors vary somewhat according to the camera model in question, but we do not know the exact specifications for either.
"That's just about as much technical info as I can provide on this topic.
Question: Same cameras. Going to the Space Shuttle launch next week. Which metering should I use. Daytime launch. The rocket flames are incredibly bright. Will be 6 miles away, using the 1DIV and 800mm. Thoughts?
IdahoBob wrote:
Question: Same cameras. Going to the Space Shuttle launch next week. Which metering should I use. Daytime launch. The rocket flames are incredibly bright. Will be 6 miles away, using the 1DIV and 800mm. Thoughts?
The light on the shuttle should be substantially similar to the light falling where you'll be, unless there is heavy scattered clouds.
If the lighting is about the same at both spots, take an incident reading or a substitute reflected reading (grass, gray card, etc.) and use that in manual exposure mode; that way it won't be fooled by the bright rocket exhaust.
As always for something like this, I'd bracket my shots.
wilt wrote:
...Chuck Westfall of Canon USA provides this response:
- snipped, but Chuck's response includes "Evaluative metering uses a variety of algorithms to determine..."
"Variety of algorithms" sounds like something garbled and heard 10th hand. It can't really be a "variety" of algorithms, it's just one. And, as Chuck's response goes on to say, they
i. aren't telling us what;
ii. aren't even guaranteeing it's consistent from body to body. So, having figured out what exposure compensations I needed when shooting with one, I'd have to do that all over again for another.
Then there's the 1D Mark III white paper (not, as stated in the forum thread you linked to, the 1Ds Mark III one), which describes what it calls the "basic concept" as (paraphrased from the poor English)
1. Metering is weighted towards the AF linked point.
2. If it sees a bright "object", the exposure is increased.
3. It increases exposure for backlit scenes, and decreases it for those with dark backgrounds.
The trouble with these three motherhood aims is that we'd expect any acceptable evaluative metering pattern to behave that way. I'd be pretty sure Nikon kept increasing their scene database until it did, for example.
