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05-08-2016, 01:16 AM   #1
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Is metering active all the time?

I read somewhere that the SR seems to be active as soon as the power is on, that is you don't have to half press the shutter button to get the little hand icon to pop up. But if you do half press the sensor is lifted to be really ready for action (which consumes power) which I find really irritating if all I wanted to do was to check the exposure settings.

But then I figured, if the SR is active all the time, maybe the metering is also active all the time?

So could someone in the know please respond if the metering is active all the time or if you still have to press the shutter button to activate it?

A related question is if I just dab the shutter button to activate the metering (if necessary), is the sensor lifted immediately or do I need to half press for a longer period before that happens?

05-08-2016, 01:20 AM   #2
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Metering is an 'on-off' sort of thing. Half pressing the shutter will activate the metering and it remains on, taking updated measurements, until a time-out, unless the shutter is pressed again, then it re-meters. The time-out can be controlled by a custom setting (I think you get 3, 10 or 30 seconds, perhaps depends on model).

---------- Post added 08-05-16 at 08:24 ----------

One advantage of the back button focusing use is that you can isolate the metering and autofocus functions to the two buttons, giving great control ...eg you don't have to refocus unnecessarily if its just the light that changed.

The sensor is held in an active state when the power is on, it may take a second or two to initialize. I believe the SR is active and instantly ready always after this initial activation.


Regarding the custom setting, if you don't tend to shoot in quickly changing light then you can save some battery drain by choosing a shorter time-out.
Remember that the AE-L (auto-exposure lock) button will temporarily hold the metered exposure value even if the meter circuit is still active, if you find you don't want it to change if the light changes.


However, if the metering circuit is still active then the exposure value will change if the light changes, eg if you move the camera around a bit before taking the shot. This could be a reason to use the AE-L function, if you don't want that to happen.

Last edited by mcgregni; 05-08-2016 at 01:33 AM.
05-08-2016, 04:12 AM   #3
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Ok, thanks. So metering works as usual.

But will the image sensor be lifted and then dropped half a second later if I merely touches the shutter button to engage the light metering?
05-08-2016, 08:06 AM   #4
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I'm not sure what you mean by ' lifted and dropped ' ....? The sensor is held in a gyroscopic electro-magnetic field, and I think this remains activated whenever the camera is switched on, so Shake Reduction is instantly available. I don't believe the sensor is released from it's active state until the camera is switched off. You can hear it clunking in they camera when it's off and you move the camera around. I don't think the sensor shake system reacts to the shutter button half press in any way, but I'm sure someone else can verify this or not.

05-08-2016, 08:19 AM   #5
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The sensor is not held in a magnetic field until you half press the shutter (or press the AF button), you can verify this by tilting your camera and listen to the "clunk" as the sensor slides around freely even when the power is on.

This clunking noise should stop once you half press the shutter button. But half a second after you let go of the shutter button the sensor "drops" again and can slide around freely until next time.

However this seems to be a new behavior with the K1, the earlier models did not lock the sensor in a magnetic field until the mirror started flipping up.
05-08-2016, 10:30 AM   #6
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I'm afraid I'm not sure exactly. Lets hope someone else will chip in as well. It seems strange to have the sensor ' dropping ' each time between shots, and why would it need to be connected to the metering circuit? I've not felt or heard the sensor in my K7 moving unless it's switched off, or working in live view mode ... Then, especially with telephotos it has to really work hard and I try to avoid this. But I didn't think it was unsupported when the camera was on .... But happy to be corrected.
05-08-2016, 03:49 PM   #7
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On the K3 the Auto Power Off time runs out, and it is awoken by a shutter push and the noise happens.
05-08-2016, 08:29 PM   #8
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QuoteOriginally posted by Gimbal Quote
I read somewhere that the SR seems to be active as soon as the power is on, that is you don't have to half press the shutter button to get the little hand icon to pop up. But if you do half press the sensor is lifted to be really ready for action (which consumes power) which I find really irritating if all I wanted to do was to check the exposure settings.

But then I figured, if the SR is active all the time, maybe the metering is also active all the time?

So could someone in the know please respond if the metering is active all the time or if you still have to press the shutter button to activate it?

A related question is if I just dab the shutter button to activate the metering (if necessary), is the sensor lifted immediately or do I need to half press for a longer period before that happens?
I can hear the SR in the K-1 when it's on. I could NOT hear the SR in the K-5 or earlier models. (edit: when it was floating; obvs you can hear it when it shakes or hits the stops. The K-1 makes a slight whisper all the time that SR is on, but only you will be close enough to hear it.)

It shuts off when the camera naps, and the noise stops. And it snaps back to life when you half press to wake the camera back up to take a shot.

I can't really say what battery life is like yet. I suspect I'm pixel peeping a lot so it's draining faster. And my comparison is skewed, since I have the LCD on the K-5 shut off, so it's lasts a long time.


Last edited by noser; 05-08-2016 at 08:30 PM. Reason: Clarified SR noise statement.
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