Author Topic: Canon 50D - controlling lens power supply  (Read 658 times)

otwieracz

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Canon 50D - controlling lens power supply
« on: May 08, 2020, 12:00:37 PM »
Hey,

I'm (frustrated) owner of Canon 50D and Samyang 35mm f/1.4 AS UMC AE lens. For a long time a was haunted by rapidly discharging camera. Not even when it use, but I just let it sit powered off for a week or so only to find it completely discharged. First I blamed old battery, but after buying new one and noticing virtually zero difference I started getting suspicious.

Finally, thank's to COVID lockdown, I found some time for debugging. After plugging with my multimeter in serial with battery I discovered that with only that specific lens my camera, even when disabled with "off" switch, is constantly draining 8-9mA of current - where stock lens is sucking 0.3-0.4mA.
Another thing confirming the issue is that when putting battery back into camera, even when disabled, I can definitely hear motor clicking inside the lens - and multimeter confirms that voltage is supplied to lens connector even when body is powered off.

Is there any way to alter this behaviour by Magic Lantern? Do you have any other ideas how to deal with such issue?

Thanks,
Slawek

Is there any way to prevent camera from supplying voltage to lens when suspended/powered off? I11

Frayfray

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Re: Canon 50D - controlling lens power supply
« Reply #1 on: May 09, 2020, 10:31:46 AM »
Have you tried with card door open and camera off and see if you get a reading cause on the door there is a micro switch on Canon models or if you installed  ml not correctly
https://www.magiclantern.fm/forum/index.php?topic=4549.0

Walter Schulz

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Re: Canon 50D - controlling lens power supply
« Reply #2 on: May 09, 2020, 10:58:56 AM »
@otwieracz: Not much ML can do. Because power switch doesn't disconnect power. It's connected to an ultra-low-power device listening all the time to switch's status. If there is an external device not working properly (sucking battery dry) your options are limited to things which will actually turning off power: Opening battery compartment door and releasing battery.
Photogs and videographers: Assist in proof reading upcoming in-camera help!. Your input is wanted and needed!

Frayfray

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Re: Canon 50D - controlling lens power supply
« Reply #3 on: May 09, 2020, 12:50:34 PM »
true that walter or get a grip with master power switch i have one on my t6i its after market  but works no battery drain

c_joerg

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Re: Canon 50D - controlling lens power supply
« Reply #4 on: May 09, 2020, 08:42:38 PM »
Seems to be normal at Samyang….
I had the Walimex Pro (same as Samyang) 14mm f2.8 AE three times. It was exchanged twice. Then I had one with another controller (recognizable by the serial number). But this was decentrally. Now I have the manual one.
6D

otwieracz

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Re: Canon 50D - controlling lens power supply
« Reply #5 on: June 10, 2020, 10:48:29 AM »
I've just got mine replaced, but I already hear that motors click inside lens after inserting battery. So I'd probably have to try return it and get refund somehow, it's useless right now.

Opening battery tray works, but after few months of such behaviour I bed I'd have to replace my battery compartment...

Frayfray

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Re: Canon 50D - controlling lens power supply
« Reply #6 on: June 11, 2020, 12:24:38 AM »
(update)i just got the 50d recently with  oem grip . the built in flash does not work and shutter button is weak but  hot shoe works. i had to replace hot shoe metal bracket from a original rebel film camera but the grip does not have a master cut off so you have to pull batteries i am not sure if a aftermarket grip would have a thing like that for 50d ?? but i did leave the battery in the grip seams to last a long time.my camera was used for time lapse photography  so it must have had some water condensation built up ..that is why i think flash is not working and shutter button needs cleaning ,i found under hotshoe rusty gunk .. after some cleaning she is all good.  :)