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Author Topic: Mark III metering  (Read 3853 times)

te4o

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Mark III metering
« on: April 16, 2012, 06:44:26 AM »
Please someone explain why is the metering under exposing 2/3 or more. Is this a design issue? To get the histogram away from the left corner I need to go +2/3'or more on almost all shots. Not that it disturbs me much but I just wonder. The 40D did not have that.
BTW has someone noticed that when looking into that huge VF you can see the mirror straight under the frame view? There is a lot of camera to be seen through this VF, no wonder the light fall off on the VF would influence the exposure ;D

Thanks for your comments.
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Mark III metering
« on: April 16, 2012, 06:44:26 AM »

PhilDrinkwater

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Re: Mark III metering
« Reply #1 on: April 16, 2012, 06:57:19 AM »
Which is the correct exposure?

te4o

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Re: Mark III metering
« Reply #2 on: April 16, 2012, 07:12:18 AM »
I agree with you, that's why I am not troubled a lot, but if you observe the histograms there is plenty of space to the right at 0 ev, I.e. much more detail in shadows can be captured than the standard meter allows. I am asking why is this happening?
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acoll123

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Re: Mark III metering
« Reply #3 on: April 16, 2012, 07:41:05 AM »
I shot my kids at a summer camp preview day yesterday and noticed everything was underexposed by +/- 1 EV. I also noticed that I was shooting in evaluative metering mode. I usually shoot center-weighted so I will change back and see if it makes a difference.
Anyone else having this issue using evaluative metering?

spinworkxroy

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Re: Mark III metering
« Reply #4 on: April 16, 2012, 07:49:22 AM »
I believe there's some issue with evaluative metering...exposures aren't correct for most parts...in fact, i'm a little different..i find my shot overexposed more often than underexposed..i almost never get spot on exposure under evaluative...Maybe i should switch back to center-weighted..but i just feel a camera of this price should have a darn good evaluative metering system..maybe it's just not so?

risc32

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Re: Mark III metering
« Reply #5 on: April 16, 2012, 08:21:13 AM »
I'm very please with the metering of my mk3. I'm also really liking the auto shadow highlighting thing procedure.

PhilDrinkwater

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Re: Mark III metering
« Reply #6 on: April 16, 2012, 08:46:35 AM »
I agree with you, that's why I am not troubled a lot, but if you observe the histograms there is plenty of space to the right at 0 ev, I.e. much more detail in shadows can be captured than the standard meter allows. I am asking why is this happening?
Well, why this is happening could be because the new exposure is correct and the old one is wrong :) That's why I'm asking :)

It may be, for example, that you like to ETTR and previous cameras have done so to meet the demands of the market and hide poor shadow noise, but Canon have decided that ETTR produces very bright and unattractive images so they've changed the metering system to darken images.

I know one of the things I see a lot from less experienced photographers (and I don't mean that in a negative sense) is overexposed images that have not been reduce in post, so which have really poor tones.

I don't know - I'm speculating I guess...

Here's a thought: take a shot with the 5d3 on 0ev and your old camera on 0ev and see which produces the *more attractive* photo. If it's the 5d3, it may be that the old system was "wrong" and the new system is "right". Post them up here if you want views from people.

Problem is that there is no right and wrong with exposure - only what the photographer wants. Much more important to auto systems like AV is that it produces *consistent* results. If it always runs at 2/3rds less than you want, leave it on 2/3 :)

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Re: Mark III metering
« Reply #6 on: April 16, 2012, 08:46:35 AM »

te4o

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Re: Mark III metering
« Reply #7 on: April 16, 2012, 09:28:05 AM »
Phil, you sound really reassuring, I don't mind the comment about the inexperienced, I pp all of my keepers.
Some more testing will help as you correctly point out, I'll do it tomorrow and report.
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nvsravank

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Re: Mark III metering
« Reply #8 on: April 16, 2012, 10:47:27 AM »
In my 5D (original) i had to underexpose by a stop manually to get bright colors and not saturate on the red channel as easily.
With the 5D Mark III, looks like the exposure is much more normal and keeps the details.

While i did not do an apples to apples comparison, this is what my subjective shooting experience has been.

PhilDrinkwater

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Re: Mark III metering
« Reply #9 on: April 16, 2012, 11:02:26 AM »
I don't mind the comment about the inexperienced
Just so you know, that wasn't directed at you ;) it was more about the idea that Canon might be trying to produce a more attractive file for people who don't PP or for whom in camera JPEGs are their work format.

PhilDrinkwater

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Re: Mark III metering
« Reply #10 on: April 16, 2012, 11:03:49 AM »
In my 5D (original) i had to underexpose by a stop manually to get bright colors and not saturate on the red channel as easily.
With the 5D Mark III, looks like the exposure is much more normal and keeps the details.

While i did not do an apples to apples comparison, this is what my subjective shooting experience has been.
The new metering system takes colours into account and does a better job of understanding how bright colours are relative to others, so it will, in theory, do a better job of metering colour scenes :)

Mt Spokane Photography

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Re: Mark III metering
« Reply #11 on: April 16, 2012, 11:10:29 AM »
The only images that appear underexposed when I check the histogram in Lightroom (one on the camera is for jpegs), are indoor images with no flash and where there is lower contrast.  They appear to be underexposed because there are no bright highlights, but outdoor images are perfect.

PhilDrinkwater

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Re: Mark III metering
« Reply #12 on: April 16, 2012, 11:13:58 AM »
As a final point for all ... what metering mode do you want to be using? For those using evaluative, is that really the best option?

From Canon http://cpn.canon-europe.com/content/education/infobank/exposure_settings/exposure_compensation.do

"Evaluative metering, the default setting for EOS cameras, takes measurements from different parts of the scene. Based on these, the camera can often compensate for backlit or off-centre subjects, but it has no idea of what the subject is, or the conditions under which you are shooting. You might be photographing a light-toned subject in poor light, or a dark-toned subject in bright light – it is all much the same to your camera.

<snip>

If, for example, the central zones are darker than the outer zones, it is likely that the main subject is backlit. If the central zones are much brighter than the outer zones, the main subject might be in a spotlight. In both cases, the camera will bias the exposure to the central zones, giving correct exposure to the subject.

In effect, the evaluative metering is implementing its own exposure compensation. An overall reading from either scene would not give good exposure, but exposure based on the central area will improve the results.

The trouble when using exposure compensation with evaluative metering is that you don’t know if the metering has already compensated for the conditions. If it has, and you dial in even more exposure compensation, then the exposure will be wrong. Equally, if you assume that the camera has got it right, but it hasn’t, then you will also have a badly exposed picture.

The solution, as with so many things photographic, is experience. After a while you will learn to recognise the types of scene which evaluative metering handles well, and those that it does not.

When you change to a different camera, you will have to learn all over again, as the number of metering zones can change the results."

I see evaluative as the most random of all of the metering modes. The camera really doesn't know what the hell is in front of it, so it takes a pure guess. You then have to guess what it's done and compensate for that. Now, from one camera to the next the algorithm could change significantly (especially with the new colour metering the 5d3 which will have a lot more information). So, maybe it's doing a much better job? Or worse? Or...?

However, the major point from me would be that it's very hard for a system like this to provide any particularly useful results because it's so dependent on the scene.
« Last Edit: April 16, 2012, 11:16:03 AM by PhilDrinkwater »

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Re: Mark III metering
« Reply #12 on: April 16, 2012, 11:13:58 AM »

PhilDrinkwater

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Re: Mark III metering
« Reply #13 on: April 16, 2012, 11:16:55 AM »
I believe there's some issue with evaluative metering...exposures aren't correct for most parts...in fact, i'm a little different..i find my shot overexposed more often than underexposed..i almost never get spot on exposure under evaluative...Maybe i should switch back to center-weighted..but i just feel a camera of this price should have a darn good evaluative metering system..maybe it's just not so?
Are you using exposure compensation?

V8Beast

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Re: Mark III metering
« Reply #14 on: April 16, 2012, 11:37:23 AM »
For the stuff I shoot, compared to my 5DC, the 5DIII tends to underexpose by about a 1 stop in evaluative mode. Centerweight, partial, and spot metering give much better results for my usage. My theory is the 5DIII's new metering system is more sensitive to highlights, but that's purely a guess. The 5DIII's evaluative mode actually performs similarly to my old 1DII. I don't see this as a problem, just something that requires a slight adjustment in technique.

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Re: Mark III metering
« Reply #14 on: April 16, 2012, 11:37:23 AM »