I would be interested in using my Canon EOS M50 for astrophotography, however I would like to take longer exposures than the 30 second limit. Is there any way to increase this limit beyond 30 seconds to take better exposures?

I considered using Magic Lantern, however I don't believe it is supported by the camera and also it was ambiguous as to whether or not that was a feature that magic lantern actually offered. Is there some sort of software that can accomplish this? I assume that this was a limit of the software rather than the hardware, but I'm not sure if I'm missing something.


5 Answers 5


You need to use bulb mode, which will allow you take arbitrarily-long exposures. To enable bulb mode, first set your exposure to Manual, then just dial the shutter speed past 30 seconds, the next setting is "bulb".

I recommend using a remote shutter release, such as the Canon BR-E1 Bluetooth remote. With the camera in bulb mode, one press of the button on the remote will start the exposure. A second press of the remote's button will stop the exposure. For a remote like this, it is up to you to control the timing (i.e., use a stopwatch or clock to time the exposure).

There are intervalometer remotes that allow you to dial in the precise duration of bulb mode shots, but I don't know if they are Bluetooth-capable. If they are, make sure they are compatible with your M50 before you buy.

  • Just to add a bit more about this, you can also use Cannon's Camera Connect app from a phone or computer to connect to your camera while it is in manual focus mode. You can then set the exposure to Bulb from your device, adjust anything else you need, then click the shutter button to start the exposure. There will be a timer in the top right corner of the app showing how long your shutter has been open. You can then close the shutter with another tap of the shutter button.
    – Vorticity
    Sep 7, 2020 at 19:30

You don't need other firmware to expose for longer than 30 seconds, you can simply use bulb mode.

You'll find that keeping the shutter open manually in bulb mode is no fun. This earlier question looks into ways of starting and stopping a bulb exposure without holding the shutter button.


Is there some sort of software that can accomplish this?

Yes. Canon's "EOS Utility" will let you do this.

Another simple way to do this is with a remote release that has a built-in interval timer (aka "intervalometer") which is a timer that can control the shutter in bulb mode (and other modes) to take a series of long exposure images.

You mentioned this is for use in astrophotography. There are a number of other applications designed specifically for astrophotography that support this as well.

You may want to look at:

  • Backyard EOS by O'Telescope is popular (Windows only).
  • AstroDSLR should work (mac only) but do their free trial to verify your model is supported before buying. (I've only used this with DSLRs ... not with any mirrorless models, but they use the Canon EOS SDK which should work regardless.)

There are many other examples but these are two that are specifically design just for dealing with astrophotography and DSLR & mirrorless cameras. There is actually quite a long list of applications, but most of them are able to orchestrate everything needed to control an observatory while also controlling the image acquisition process (i.e. they may be more complex than your needs at the time).

What's so special about them?

There are a number of special techniques used in astrophotography -- especially if the camera is connected to a telescope and the telescope is mounted on a computer-controlled mount.

  • They allow sequencing of the "light" (normal exposure) frames but also allow for sequencing and organization of special calibration frames such as "flat" frames, "bias" frames, and "dark" frames.
  • They coordinate with auto-guider software to control telescope moves for dithering (used to help reduce/eliminate noise) and drizzle (used to improve resolution)
  • They typically include special features to help with focus by leveraging techniques to help improve focus accuracy and may integrate with auto-focus systems for telescopes that have motorized focusers.
  • They may integrate with plate-solving software to help accurately center the telescope on the object of interest. These objects are usually too faint to be seen visually.

This may be ... almost overwhelming for someone who only asked if there is software that can control the camera for long exposures. If you are connecting the camera to a telescope, you'll benefit from learning about these special techniques used in astrophotography (specifically how to "auto-guide" during image capture) and also how to do "image stacking" (image calibration and integration) to get much cleaner images.

If you are not connecting the camera to a telescope, then using a remote shutter release for your camera that has a built-in "interval timer" will certainly be easier and/or use a computer running EOS Utility to control the image capture sequence of long exposure images.


The Bulb mode allows users to set a very slow shutter speed for long exposure photography. https://www.practicalphotography.com/camera-advice/questions-and-answers/what-is-the-b-mode-on-my-camera-for


I use Alpine Labs Pulse unit https://alpinelaboratories.com/products/pulse-camera-remote I control it from my phone via their app.You can set the length of exposure and number of exposures.

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