I plan to use my Canon 50D in a studio, tethered to a PC.

It would be great if it drew the power it needed from the USB bus rather than from the battery, so I wouldn't need to worry about changing batteries (and moving the camera) during the shoot.

Can anyone please tell me if the Canon 50D will (or can be made to) draw power through the USB port?

4 Answers 4


Based on the reading of the battery spec, no. The battery pack supplies 7.4v, while USB can only supply 5v. However, you can buy the ACK-E2 wall power kit to power the camera directly from a standard outlet.


An USB 2.0 port can only supply at most 500 mA of power, and that is simply not enough to run a camera on.

  • I thought it was up to 1A ? Nov 18, 2010 at 8:50
  • 2
    For USB 2.0 the limit is 500mA and for USB 3.0 the limit is 900mA
    – labnut
    Nov 18, 2010 at 9:11
  • 3
    do you have any specs or references for what the Canon, or any DSLR, needs? I would have thought 0.5A @ 5V would be enough to drive the mirror and sensor - maybe not the built-in flash. Maybe I haven't got a good feel for it though. Nov 19, 2010 at 8:14

The Mini USB won't give you any power to or for the camera.

But when you have it hooked up, the camera's battery is used up much faster.

Three answers: 1. Canon ACK-E2 (Fake battery adapter). $60.00, but you have a cord. 2. Canon vertical grip. $300 and about a pound of weight 3. ATG AK1 Un-Tethered Systems. $500, very light. Image/Live-View/flash-wirelessly with many cameras!

  • I ordered a cheap knock-off to the Canon ACK-E2 when I saw the first responses. Arrived before my photo-shoot, and once all the plugs and cables where duct-taped together to stop them falling out, it solved the problem perfectly. Dec 27, 2010 at 12:47
  • 1
    The "ATG AK1" is a questionable product: photo.net/canon-eos-digital-camera-forum/00XQ5w So far there is no proof that it actually exists. Jan 31, 2011 at 16:34
  • How much did you get that Canon ACK-E2 and from what site?
    – zesix
    Jan 31, 2011 at 16:38

I have used a generic Canon AC power supply from Amazon (about $15 give or take for various models) for over a year with no problems, except for (as also mentioned in another review) the necessity of securing in place various cable connectors: be sure and use only ONE layer of THIN electrical tape to hold the power connector into the battery adapter, or risk damaging the camera due to the battery adapter getting stuck in the camera. Maintain a power backup: don't throw out the batteries!

I agree with Guffa that using a USB 2.0 powered hub of 5 VDC / 500 ma (2.5 watts) is not enough to power this camera's USB data transfer requirements. You will end up with a series of blown USB hubs (if you are lucky) or (more problematic) a blown PC USB power supply. Cameras used are T2i and T3.

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