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Delayed Shutter on M8 and Battery


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It is just my impression or when using the firmware-activated delayed shutter on the M8, the battery goes down two time faster?

It is possible that this depend on how long one keeps the rewind delayed before releasing the finger from the shutter button?

Maybe this is a silly question but I've only used the delayed shutter for the first time a cople days ago.

Anybody else experincing this

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Actually, Mark's measurements and analysis, as I read them, seemed to indicate that if you let up on the shutter button BEFORE the M8 stopped writing the file to the SD card (flashing red light on the back) then there was no extra power hit from using Discreet Advance.

 

However, I was fairly careful to always let the shutter wind on before the red light stopped flashing - and STILL noticed a big drop in battery life.

 

It would be interesting to know if this is also true with the M8.2.

 

Perhaps Leica really did change the power-management hardware in the .2, which is why they originally said, last fall, that DA could not be offered as an upgrade for the original M8. Too much power drain unless the hardware is upgraded as well.

 

Then they figured, what the heck - let users choose between DA or better battery life, as appropriate to their needs.

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My measurements were done on an unmodified M8. It's definitely the case that if you prolong the delay (by keeping your finger on the shutter release) beyond the end of the memory card write (flashing red LED), you will incease the power consumption and reduce the battery life.

Edited by marknorton
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Mark, what were the current levels that you saw in the three basic states:

 

shutter half-pressed, camera ready to fire (and I guess holding down the shutter to delay rewind falls into this category)

 

shutter button up, dng written to memory, but camera still active because the 2 minute time out hasn't happened

 

camera sleeping, power switch on, but all lcds and leds off.

 

scott

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Scott, to post this picture again (and bore everyone), the vertical scale is 0.5A per major division, 100 mA per minor division.

 

1. At the start, the camera is idling, power switch on, shutter release not depressed - 200mA

 

2. Press the shutter release to switch on the meter and camera electronics - 600 - 700 mA

 

3. Take shot, peaks to 2A, motor wind up to 1.5A (dome shaped peak)

 

4. Image processing and write to card - 700 - 800 mA

 

5. Revert to idle in 2 stages - back to 200 mA

 

6. When the camera is asleep (battery/frame counter LCD off), the current is close to 0, much less than 1mA if I recall.

 

Roughly, taking a shot is 3.8V * 0.8 A * 10 seconds = 30 Watt-Seconds. Idling is 3.8v * 0.2A = 0.76 Watt-Seconds, so idling consumes the same power, ROUGHLY, as taking one shot every 40 seconds.

 

[ATTACH]141160[/ATTACH]

 

[Edit: actually, the camera was being fed with a constant 4.2v here, not the nominal 3.8 from the Li-Ion battery.]

Edited by marknorton
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Mark, do you know if the act of turning the camera on releases a surge of power beyond that of the idling levels? I often just turn the camera off rather than letting it idle, but don't know if that is an inefficient use of battery power.

 

Thanks, Doug

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Doug, I haven't seen anything like that but in the interests of wear and tear on the power switch, it would be much better if Leica provided the "fast sleep" setting instead of relying on the user to use the power switch (which of course does not actually interrupt the power, simply signalling to the microprocessor to go to sleep at the first available opportunity, for example, when a current write operation to the SD card is complete).

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Mark, ....

I often just turn the camera off rather than letting it idle, but don't know if that is an inefficient use of battery power.

 

Another way to read the last line of Mark's post is that leaving the camera in active idle until a 120 seconds timeout (the shortest on the menu) consumes as much power as taking three shots and turning the power switch to off right after each shot. This is the reason to ask for a 20 sec timeout, or instant wakeup rather than the fairly power-hungry on state that the camera currently offers.

 

I can't recall if Mark's measurement (done on an unmodified M8) was done with 2.002 or 2.004 back in March, so the question of whether holding the button down in Discreet mode costs even more than just leaving it on has probably not been answered yet.

 

scott

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Scott, they were done with V2.004 and if you keep your finger on the shutter release, the electronics remains active. The rule of thumb is that if you allow the shutter to recock before the red LED stops flashing, there's little overall effect through using dicreet mode; if you delay it further, the electronics is kept awake for longer and will cost battery power.

 

That dome shaped peak is all there is to the shutter wind and it moves according to where the wind takes place. It also shows that the shutter wind is not a big deal from a power point of view and there would be little advantage in delaying the wind. Any advantages are more to do with noise and operational "feel".

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