Traditionally all consumer grade cameras have a pretty severe weakness in that they have poor Dynamic Range which means you typically can only capture the highlights or the shadows. What if you could instead record both at the same time with the same camera, welcome to Magic Lantern on the EOS M series of cameras.
In this post, I’ll walk you through how to use Dual ISO in crop mode to unleash up to 13 stops of dynamic range from this compact powerhouse. Whether you’re just getting started or you’ve tried and failed in the past, I’ll break down the full process—from setup to post-production.
What Is Dual ISO and Why Use It?
Dual ISO is a Magic Lantern feature that essentially blends two ISO values in the same frame, typically a low and a high ISO. This allows you to retain highlight detail while recovering shadows, effectively expanding your dynamic range. On the EOS M, you can get an extra 2.5 stops, which makes a huge difference in high-contrast scenes.
Setting Up Dual ISO on the EOS M
Getting started is simpler than you might think:
- Enable Dual_Iso Module
Open Magic Lantern menu and go to the modules tab. Make sure you have enabled Dual_Iso.mo. You will have to restart the camera if you haven't done this prior to load the module.- I also take the time here to set the INFO button as the enable/disable Dual ISO for simplicity when taking video and not having to bounce into and out of the menu. (Prefs / Customize Buttons / INFO Button: Dual ISO
- Frame Your Scene
Pick your shot and compose as usual. It’s best to do this before enabling Dual ISO since the live view gets a bit glitchy afterward. - Expose for Highlights
Use the histogram or EV meter and expose just under the clipping point. Ideally, you want the exposure reading close to 0.0 or slightly under, like -0.4. - Enable Dual ISO
Go into the Magic Lantern menu, under the exposure tab, and turn on Dual ISO. The standard setting is 100/800, which is a good balance between noise and dynamic range. Higher settings like 100/1600 or 100/3200 introduce more noise, so I tend to avoid them.- Also if you have a higher value than 100 you need to go into the normal Canon settings for ISO and change it to 100.
- Focus First, Then Record
Since the Dual ISO live view is hard to use for critical focus, make sure everything is sharp before enabling it.
Hit record, and you’re done with the capture side!
Processing Dual ISO Footage with MLV App
Once you've shot your footage, processing it correctly is key. Enter the MLV App, a tool specifically designed for working with Magic Lantern RAW files.
- Activate Dual ISO Processing
Select a clip and look for the “Dual ISO” tab. Click to activate it—this transforms your footage from a strange interlaced mess into a clean image with enhanced dynamic range. - Grade and Export
In MLV Apps "Processing" area you want to boost shadows and tweak exposure to taste. I usually apply a Sony S-Log3 profile and export [ Gears Icon ] as Apple ProRes 422 LT for a solid balance of quality and file size. You can then bring the footage into DaVinci Resolve or your preferred NLE for final grading. - Import Your Footage
Insert your memory card and open the sd card you recorded onto. Select all the clips you need and import them.
Final Thoughts
I’m genuinely blown away by how powerful this feature is, especially considering the EOS M is a $150 camera. It took me a while to get it working reliably—probably due to newer builds like Bilal’s crop mood—but now it runs flawlessly.
If you’ve got any questions, feel free to drop them in the comments. Otherwise, happy shooting—and enjoy all that extra dynamic range without breaking the bank!
