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Multifield Metering


krooj

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Question - Thorsten's website hints that Multifield Metering only works when in live view, so in the SET menu, if I have MFM selected but am not using LV, what metering mode does the camera fall back on? Centre-weighted? Spot? Or, and I don't think this is the case, based on the shutter cycle sound, does it force the camera to use Advanced Metering?

 

:confused:

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When not using LiveView, but having selected Advanced metering, the camera opens the shutter to perform metering, as soon as the camera is turned on or as soon as "Advanced" is selected. Opening of the shutter does not happen in "Classic" mode.

 

You can tell from the sound, but also from the exposure metering: select a bright surface with something dark in the side of the frame: in "Classic" mode you get a shorter exposure than in "Advanced" mode, showing that in "Advanced" mode , the dark opbject is put into the equation, while in "Classic" mode it is not.

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I get what you're saying. My 240 is set to classic metering, but if I hit the SET button, I see three options for exposure metering: spot, centre-weighted, and multi-field. To my mind, with classic metering selected, only two of those options should be possible when not using live view: spot and centre-weighted. Having multi-field in that menu makes no sense, unless they mean multi-field in live view only OR you have advanced metering set, which also implies that there must be a fallback to either centre-weighted or spot when using classic metering and toggling live view off. It's important to know which one it falls back to in order to trust the meter.

 

It doesn't really matter to me, because I am going to keep the camera in classic, centre or spot metering, almost all the time. It's just a confusing part of the menu.

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Ah, thanks for the explanation.

 

One possible disadvantage: keeping the shutter open all the time when the camera is on seems like it could be an invitation for dust to migrate on to the sensor (even when a lens is attached).

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if I hit the SET button, I see three options for exposure metering: spot, centre-weighted, and multi-field.

 

Those options only apply to the "Advanced" metering mode. "Classic" is always by bouncing light from the shutter blades to the lightmeter, so there is only one way of measuring light: centre-weighted and the shutter is closed during measurement.

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Again, it makes sense to do the experiment yourself: Switch to "Classic", aim at a scene on tripod with an even bright surface and one dark part on the edge of the frame and perform the 3 measurement modes to see if the exposures differ. (I've done it and the result is not surprising: it makes no difference which of the 3 modes you select)

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Those options only apply to the "Advanced" metering mode. "Classic" is always by bouncing light from the shutter blades to the lightmeter, so there is only one way of measuring light: centre-weighted and the shutter is closed during measurement.

 

I see - so it's a bug in the firmware. The list of exposure metering possibilities should be driven by the light metering mode, but it is currently a static list.

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I would not call that a bug. A bug is generally an error in software that leads to malfunction. Although your suggestion may be useful (leaving out menu items that do not apply), as long as you know what the options mean, there is no problem in the function of the camera.

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The other thing to remember in Advanced mode is that there is a very small shutter lag which you don't get in Classic. I generally stick to Classic for this reason...

 

According to my measurements, the shutter lag is equal on average in both "Classic" and "Advanced" modes: 0.08 sec. (1/360 sec exposure time) averaged over 10 measurements (stdev 0.015 sec).

 

Method: photographing digital stopwatch, pressing stopwatch and shutter at the same time, while switching hands halfway the set to check for systematic differences between hands. In all cases the shutter was half depressed before final release.

 

However, I agree with the conclusion: most of the time Classic is fine: you are used to its characteristics, there is less battery current and less extra sounds. Sometimes spot measurement is interesting, while multi-field measurement can be of use in wild situations like photographing through a tunnel with light at the end.

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Great 411 I wonder how long the meter takes in A for the meter to react ...set a different exposure, say your on a street corner with the light coming behind you low sun strong light you aim on a person in the hard strong light but they are only half or a third of the frame . Set the focus the person moves slightly out of the strong light you dial in the focus and fire. Did you get the exposure correct on the first frame? In other words how fast does it (the meter) adjust in A mode?

 

Another question what takes priority highlight mid tones or shadows...I still feel the m240 is similar to the m9 and in those situations it under exposes!

 

regards

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Great 411 I wonder how long the meter takes in A for the meter to react ...set a different exposure, say your on a street corner with the light coming behind you low sun strong light you aim on a person in the hard strong light but they are only half or a third of the frame . Set the focus the person moves slightly out of the strong light you dial in the focus and fire. Did you get the exposure correct on the first frame? In other words how fast does it (the meter) adjust in A mode?

 

regards

 

The metering is at least as fast as the shutter can fire in repetition. So nu suprises there. In "Advanced" mode that is much slower than in "Classic" mode, unless you use "C" on the shutter dial.

 

To show that the meter is very fast in "Advanced" metering mode, just look at exposure time in "Auto" shutter speed mode and in "Advanced" mode and without pressing the shutter button, turn the camera fast to a bright object in spot mode: It is instantaneously changing exposure time.

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