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Author Topic: 5D3 and 24 1.4 II L Edit, and other Lenses, owners please read!  (Read 10440 times)

luciolepri

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #30 on: May 23, 2013, 05:35:11 PM »
Knowing that, you can also use it to your advantage. E.g. if you know you want bright sign to be exposured correctly, use focus points on that one, and also if you want ambient proper but focus, you can e.g. exposure lock somewhere else and re-compose.

Well, if you have to do that, what's the point in a "63 Zone Dual-Layer Metering"? Just use the spot exposure!

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #30 on: May 23, 2013, 05:35:11 PM »

dr croubie

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #31 on: May 23, 2013, 06:07:30 PM »
Theory!

Flipping the switch triggers metering. Since evaluative metering invokes code that looks at multiple metering points and tries to intelligently guess what to do, it's somewhat reasonable to assume that it might a different decision on what to do each time it's invoked if the light entering the lens in non-uniform across the image.

A way to test if this is happening is to point the camera so the image is completely uniform in brightness across the image — at the sky, or a flatly coloured wall, etc.

This makes perfect sense. Evaluative metering is linked to the selected AF point. Switching to MF deactivates all of the AF points, which means evaluative metering can no longer be weighted toward a selected point.  The fact that you're seeing this only with a wide angle lens is not unreasonable.  With such a wide FLV, there's more in the scene to affect the metering when it is no longer weighted toward the selected point. 

Theory confirmed, on my 7D & EFs 15-85 as well. Standing outside, with single AF point on the top of the frame, focussing on some bright clouds, in the bottom half of the frame is my neighbour's relatively dark roof. On AF, I get 1/500s. Switch to MF, I get 1/320.

What Neuro said is also applicable to the 7D, metering is weighted more towards what is in focus (in my case, bright sky at infinity). If it doesn't know what's in focus (from being in MF), then it will give even weight to the whole frame and meter more for the dark roof. This is pretty much what the user manual states.

It's not a bug it's a feature.
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luciolepri

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #32 on: May 23, 2013, 06:49:32 PM »
It's not a bug it's a feature.

Yeah, that's just how the exposimeter works with zone metering & AF mode selected, it was like that even with analogic cameras, the point here is that in the 5D Mark III the metering bias is too high.

Louis

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Re: 5D3 and 24 1.4 II L Edit, and other Lenses, owners please read!
« Reply #33 on: May 23, 2013, 07:56:20 PM »
Great response and i've learnt something thank you! I've never noticed this as i hardly ever shoot manual, anyone know why it seems to be more erratic on my 24 1.4 lens and not my 100mm, ? more testing needed etc

It seems then that the evaluative metering will start from the point of focus, but when switched to manual it will whole scene giving a brighter exposure
« Last Edit: May 23, 2013, 08:01:19 PM by Louis »

neuroanatomist

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #34 on: May 23, 2013, 08:12:21 PM »
...in the 5D Mark III the metering bias is too high.

I wonder how all the people clamoring for the 5DIII to have AF-point linked spot metering would feel about that observation?   ;)
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Pi

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #35 on: May 23, 2013, 08:19:40 PM »

What Neuro said is also applicable to the 7D, metering is weighted more towards what is in focus [...]

This is how Canon's evaluative metering worked since the 300D (at least). I noticed however that my 350D and my 50D were more sensitive to the AF point than my 5D2.

Pi

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #36 on: May 23, 2013, 08:25:34 PM »
I shoot other Canon and Nikon bodies, a 40D, a 600D, a D800, and I must admit that they have much better and more enjoyable evaluative metering algorithms, and I actually trust those cameras much more than my otherwise beloved 5DmkIII, that actually I trust not at all in high contrast situations.

What do you mean by "trust"? You are the one responsible for the exposure. You just need to understand the algorithm and use it appropriately. There is no perfect algorithm and the camera cannot know how you want to expose.

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #36 on: May 23, 2013, 08:25:34 PM »

LetTheRightLensIn

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #37 on: May 23, 2013, 09:10:20 PM »
Theory!

Flipping the switch triggers metering. Since evaluative metering invokes code that looks at multiple metering points and tries to intelligently guess what to do, it's somewhat reasonable to assume that it might a different decision on what to do each time it's invoked if the light entering the lens in non-uniform across the image.

A way to test if this is happening is to point the camera so the image is completely uniform in brightness across the image — at the sky, or a flatly coloured wall, etc.

Please bear in mind that I don't own this lens or camera, but I do have experience in programming. In algorithms like this, it's often the case that there's some guesswork involved — hell, I once implemented an algorithm that would just randomly choose one of tho values if it couldn't determine one value over another with any degree of certainty, and it worked just fine.

Since I doubt the camera saves the reasoning behind its metering decisions between each metering, I can easily see this sort of thing happening in something that's supposed to be "smart" like evaluative metering. If you require absolutely consistent metering, I guess evaluative isn't the right mode to choose.

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risc32

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #38 on: May 23, 2013, 09:21:46 PM »
...in the 5D Mark III the metering bias is too high.

I wonder how all the people clamoring for the 5DIII to have AF-point linked spot metering would feel about that observation?   ;)

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Re: 5D3 and 24 1.4 II L Edit, and other Lenses, owners please read!
« Reply #39 on: May 23, 2013, 09:29:15 PM »

It seems then that the evaluative metering will start from the point of focus, but when switched to manual it will whole scene giving a brighter exposure
Makes sense

tpatana

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Re: 5D3 and 24 1.4 II L Edit, and other Lenses, owners please read!
« Reply #40 on: May 24, 2013, 01:32:49 AM »
Does spot metering only use the center circle area?

GMCPhotographics

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #41 on: May 24, 2013, 05:53:09 AM »

What Neuro said is also applicable to the 7D, metering is weighted more towards what is in focus [...]

This is how Canon's evaluative metering worked since the 300D (at least). I noticed however that my 350D and my 50D were more sensitive to the AF point than my 5D2.

Yep my old 5D classic was really AF hotspot prone too. In fact every Canon SLR I've used has always been highlight shy, even my old A-1 film slr. In the Digital world this is a good thing because we should all be shooting to preserve our highlights if possible.
AF linked metering is a good thing and not a bad thing. Otherwise all our compositions would be centrally placed to match out metering.

canikon

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #42 on: May 24, 2013, 08:46:54 AM »
I shoot other Canon and Nikon bodies, a 40D, a 600D, a D800, and I must admit that they have much better and more enjoyable evaluative metering algorithms, and I actually trust those cameras much more than my otherwise beloved 5DmkIII, that actually I trust not at all in high contrast situations.

What do you mean by "trust"? You are the one responsible for the exposure. You just need to understand the algorithm and use it appropriately. There is no perfect algorithm and the camera cannot know how you want to expose.

You are right, knowing and using the equipment is owner's responsibility. But let me give to you one real example. I was in NYC last year, and at night I suddendly saw a Fire Brigade truck coming full throttle to cope with an emergency, with all the light on, and lots of people staring. I felt it was a nice shot to catch, pulled out my 5DmkIII with 24-105 and fired a couple of shots. Well, both those shots were unfortunate in the sense that the AF point was near or on one of the head light of the truck, and the pic was completely dark except 5 or 6 perfectly exposed head light of the truck. Now that pic was pretty unusable, and a waste.
The real problem is that the designer does not consider two important things:
1. to put a "cap" on the exposure shift, say max 2 stops
2. to consider that with a 63 zone metering system, you cannot distinguish if a light source is wide enough to be "significant" to the photographer, or if it is a 1% of the image area completely irrelevant as in my case was the truck head light.
I assume that 1DX (and D800 as well) having a metering system with 100K points, are far more "intelligent" in knowing if a bright point source is big enough to be of some significance or not.
All in all, this evaluative metering is not evaluative at all, and should be marketed as AF-linked spot meter, giving *another* exposure choice as true evaluative metering option.
Note that in the last 3 images I linked above, the "evaluative" metering when in MF gave the same result as the average metering, so that the evaluative is not "intelligent" or "different" at all, at least in this example.
Tis is my opinion btw, just my feeling about this feature.
« Last Edit: May 24, 2013, 10:09:11 AM by canikon »

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Re: 5D3 and 24 1.4 II L owners please read!!!!!!!!!!!!
« Reply #42 on: May 24, 2013, 08:46:54 AM »

tpatana

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Re: 5D3 and 24 1.4 II L Edit, and other Lenses, owners please read!
« Reply #43 on: May 24, 2013, 03:30:23 PM »
Best would be if they had couple custom metering settings, where (advanced) user could input they own formula how to calculate the exposure based on the information coming from the metering system.

alexanderferdinand

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Re: 5D3 and 24 1.4 II L Edit, and other Lenses, owners please read!
« Reply #44 on: May 24, 2013, 04:29:31 PM »
I had several cameras, analog, digital.
The 5d3 is the worst one in  the discipline "exposure to the left".
Too conservative. A very small bright spot- a very dark file.
(good for high contrast, but .....).

The 1d4 is more honest (?), more intelligent(?).
And so is the Sony RX100.

Didnt notice a difference using af- mf, will watch this in the future.



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Re: 5D3 and 24 1.4 II L Edit, and other Lenses, owners please read!
« Reply #44 on: May 24, 2013, 04:29:31 PM »