Finally understand the naming system of Olympus OM-D E-M10 MK II

Published by Markus on

Markus Raab taking photo with his Olympus OM-D E-M10 Mark II banner cropped

Finally understand the naming system of Olympus OM-D E-M10 MK II

There have been a few discussions already about file names of your shots with the Olympus OM-D E-M10 Mk II. I think the system to name the files is ridiculous but maybe I did not fully understand the logic behind it as of now. Can you confirm, correct me, explain?

If I understood it right you should format your SD card every 10.000 shots, no matter if you delete photos or keep them on your SD card.

10.000 is a lot of photos, but let’s say you experiment with time-lapse, then you’ll reach that number faster as you might think.

Why so?

In a file called P9049777.jpg

P is a character randomly chosen by Olympus (probably means Picture)

  • 9 is the month 1-9 = January to September, A=October, B=November, C=December
  • 04 is the day
  • 9777 is the sequential number of pictures taken

BUT: The sequential number does not start from zero (0000) on a new day, it just goes on counting sequentially.

  • P9049777
  • P9049778
  • P9059779 (next day)

After it reaches 9999 (so 10.000 photos taken in total) the camera will generate a new folder on your SD card and start from 0000 again.

  • 100OLYMP (first 10.000 shots)
  • 101OLYMP (second 10.000 shots)

From my point of view, this will mess up the order if you sort your photos by filename on your computer. There is even the possibility (although unlikely) that you get duplicated file names.

  • 100OLYMP (first 10.000 shots taken)
    • P9049777 (Monday)
    • P9049778
    • P9059779 (next day – Tuesday)
    • P9059999
  • 101OLYMP (second 10.000 shots taken)
    • P9050000 (still shots from Tuesday)
    • P9050001

Now copy your photos from your SD card to the computer and have your files sorted by name.

  • P9049777
  • P9049778
  • P9050000 (taken later in time)
  • P9050001 (taken later in time)
  • P9059779 (taken earlier in time that day)
  • P9059999 (taken earlier in time that day)

Do you see my confusion? Did they really not consider that?

PS: I understand that I am able to sort the files in my operating system by create date.

Categories: tech


Markus is a passionate photographer, WordPress web developer, Atlassian Confluence & Service Desk enthusiast, and a self-motivated lifelong learner. After different professional studies and some years on the corporate career path, he decided to try an entirely different approach and completely turned his life upside down. Pausing his career, going off the beaten path in life and on backpacking travels and discovering his true self.


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