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external power, firmware updates


scott kirkpatrick

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Since no one seems to know and the information manual doesn't say, I asked info at leicacamerausa if you can use external power to run an M8 while tethered under control of its supplied software, and how is a firmware update done? Got an answer a few hours later:

 

there is no provision for external power. Use the battery.

 

firmware updates -- no information has been distributed, but expect the same as with the DMR -- download update and write it to an SD card, insert card...

 

posting here in case anyone else was curious.

 

scott

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The obvious and very simple solution would have been for them to suck power off the 5v from the USB connector to power the camera. Tons of devices work this way. That might have made way to much sense though ;)

 

_mike

 

It would take a little extra work, since a Li Ion battery puts out 3.7V varying over the charge/discharge cycle, and the camera is set up to start with that voltage inside. That's what I thought they might be doing, since you can't do much with the tethered capture software until there is a USB connection. let's see, the battery is spec'd at 1900 mAHr and should be able to take 500 shots before discharging, that's about 4 mAhr that the battery has to provide for each shot. If you shoot 100 frames per hour in the studio, the average current that an external source would have to supply is 400 mA. I don't know the USB spec, but I would be nervous about asking the USB port to handle more than about 100 mA in current supply, so that may be the answer to the "obvious" solution.

 

scott

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Well the 5v to 3.7 conversion is VERY simple, and the single chip component to do so is VERY common. Every cell phone that charges via usb (most motorollas and most high-end smart phones) Converts the 5v to 3.5-3.7v If you look in your phone you'll more than likely see a 3.5-3.7v lithium-ion or li-poly battery. As that voltage is the standard for those cells. As far as the max mA from a USB port, well that varies slightly depending on the chipset in the host device, but it looks like 500 mA is a standard max ( Universal Serial Bus - Wikipedia, the free encyclopedia ) Keep in mind the actual mA delivered to the camera could be HIGHER due to the 5v>3.6v downconversion, depends on the efficiency of the chip doing the conversion. Either way i find it hard to believe that this camera will be sucking more power than some of the bazaro USB devices out there.

 

I'm also very disappointed that you can't actually charge the battery via the USB port. This is a simple and very common thing now days. It's great for me because I travel a lot and instead of carrying 50 different chargers I can charge a number of devices via my laptop usb ports or a compact usb wall wart.

 

_mike

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Hmmm. So 500 mA is at least legal (but maybe not the wisest thing to expect -- in the PC business there is a somewhat relaxed attitude towards meeting specs). And I used 100 pictures per hour to get my estimate of average power consumption, buffered by the battery, which may be too high for most people. But still this kind of operation is at the hairy edge of Leica's worst-case, belt-and-suspenders design philosophy. If there is real demand, they might come up with an external power plug that fits into the battery compartment, replacing the battery. My Ricoh GR-D has something like that. Oh, I forgot, the bottom plate would make access difficult.

 

scott

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