SD card for EOS M

Started by Nick-Sanchez, March 10, 2019, 06:08:55 AM

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Good day to all participants and activists of the forum! I am new to using the Magic Lantern firmware, but before I created this topic I spent a lot of time searching for the information I needed, but I ran into a problem I can't solve without your help.

I just bought a Canon EOS M camera yesterday and bought a new Transcend's SDHC 300S 32 GB card for it ( - link to product description). According to the specifications, the card supports read speeds up to 95 MB / s and write speeds up to 45 MB / s. I cannot test for performance on my PC, as there is not a sufficiently fast card reader, but the benchmark tests of the camera showed the following results:

Before the test, I formatted the card on my PC under the exFAT file system, then copied the ML firmware files to the card, reflash the camera, and then made a benchmark. The benchmark data, by the way, correspond to the information that the module displays. When I try to set the resolution parameters, etc., while recording RAW, focusing on the theoretical card bandwidth (up to 40 MB / s), the recording ends after the first few frames.

Tell me please, what am I doing wrong?

Walter Schulz

Most M users here run Sandisk Extreme Pro which is not showing the dreaded "Shutter Bug".

The only thing you did wrong is getting a card not able to keep up with specs (as otherwhere reported, too). Can't exclude faked card either. And that's not bad because refunding should be easy.
And get yourself a decent cardreader, see -> Reviews -> Card readers


There are Sandisk Extreme Pro cards of 300mbs read speeds and very high write speeds as well as cards that are 95mbs Extreme Pro. Not sure which to buy.
5DC, 5D2, 5D3, EOS M, too many lenses.

Walter Schulz

Performance of those 300 MB/s cards (UHS-II interface) is inferior to 95 MB/s cards (UHS-I). When used in cams with UHS-I interface ... and your M doesn't have UHS-II.


Got it. What about the 170 mbs Extreme Pro cards?
5DC, 5D2, 5D3, EOS M, too many lenses.

Walter Schulz

170 MByte/s is for read only and the only devices known today to use Sandisk's proprietary overclocking mode are Sandisk's newest cardreaders. Running there write rate is indeed higher, too. But with other devices they are only a tad slower compared to 95 MB/s and we don't know if older controllers (used in your M) are able to get unlocked.

EOS.M user

Hello guys, I don't want to start yet another topic for a similar question, so I decided to use this one.
Could we make a small survey? Here we can write the SD card model you used and results you could reach(resolution in 2,5K mode, writing speed, etc.).
I already tested EOS M with a few types of SD cards. And that's what can I say:

Transcend 300S SDXC 64GB Class 10 UHS-I U3 V30.
Very bad. I could even write continuous mcm1080Rewire. Write speed about 30 MB/s.

Kingston Canvas Select Plus SD Card, Class 10 UHS-I, 100MB/s, 32GB
Quite good for this price. I've reached continuous mcm1080Rewire.  Not suitable for 2.5K mode. Write speed about 36 MB/s.

SanDisk Extreme Pro 170MB/s UHS-I U3 V30 64GB
Good but relative expensive.  Continuous mcm1080Rewire,  2.5K mode about 2.25K(16:9) continuous(not dynamic scene), Write speed about 55 MB/s.
Results are very similar to

SanDisk Extreme Pro 95MB/s 128GB.
Almost the same results as for  Extreme Pro 170MB/s.


From my own experience recently with using the EOS M

Integral Ultima Pro 10 UHS-1 V30 U3 - 128GB

Running the benchmark test with Global Draw on across all SD overclocks getting 56MB/s.

Works fine in the HD mode, I have shot in the 2.5K mode and had pink frames here and there as using an external monitor. According to Zeek setting the FPS override can fix this.

At £18.99 in the UK, and $25 US seems like a decent choice to go for.


2.5K is quite demanding on the camera, dropped frames will appear. Try the 2.5K HDMI Preset, should work better, although not perfect with monitors.



Okay, so 2.5k is a but much for an EOS M, I'll keep that in mind.
I did have issues with frames, but didn't think this could be the cause...


dont use histogram - it creates pink frames, also dont  use digic peaking.THey create demand on cpu which displays histo for you at the expense of incompelte frame here and there.
All these helpers and stuff just turn it off once you setup framing and exposure, just turnoff global draw when recording, record in 10 bits if not possible to record in 12


Please tell me, my SanDisk 64GB Extreme PRO SDXC UHS-I Card - C10, U3, V30 is not detected by the camera. What is the problem?

Walter Schulz

Are other cards detected? Is card readable in cardreader?
My EOS M won't read cards with slight mechanical defects. The corner where pin 8 is located is prone to mechanical damage and plastic edge will come off quite easy.
Check and compare to working cards.


I have the exact same defect! It's some kind of mysticism! The card works fine on the 6D mark II, but the EOS M doesn't see it. I'll buy a new card, thanks for the support

Walter Schulz

Quote from: kadushkin90 on May 25, 2021, 03:27:16 PM
I have the exact same defect! It's some kind of mysticism! The card works fine on the 6D mark II, but the EOS M doesn't see it. I'll buy a new card, thanks for the support

No mystery. Your cams have different mechanical SD-card slots. My "defunct" card works well in 650D and cardreader but not in EOS M and 550D.