E-M1 mkII Dual Card Slots Gotcha!

I wanted to go over how to use the dual card slots since this is a very critical area that none of us can afford to not understand.  If you don’t understand what I write here, or don’t want to learn… then DON’T USE TWO CARDS.  Only use slot one and pretend the camera is just like any other one.  However, if you want to take advantage of the features…pay attention to the following:


Your card slot settings are programmed into the custom sets!  Repeat: Your card slot settings are programmed into the custom sets!

This means if you change to a different preset or switch to manual mode your save settings for your cards will go back to it’s set DEFAULT.  You CANNOT assume your cards are saving the way you set them once.  You must ensure you set them and then program that into your Custom Set.  To ensure your settings stay as you expect, do the following:

  1. Custom Menu H1 – Card Slot Settings.  This is where you adjust from.
  2. Go into either P, A, S, or M mode on the mode dial.  Go to Custom H1 and set you card settings as you wish.
  3. If you have already saved your Custom Sets C1, C2, or C3, turn your mode dial to that setting.  Adjust your card slot settings and resave that custom set.
  4. If you haven’t saved your custom sets, then make sure you set your card slot settings prior to saving the Custom Set.

This allows you to have different card slot settings for different modes.  So maybe you have a custom set where you want video to one card and jpg to another.  Or a set that has all images going to both cards as a backup.  Regardless, be aware that if you program different behaviors into different settings, this will change as you change your sets.  And the PASM mode retains the last one you set in that mode.  Be aware of that.  The last thing you want is to think you cards are saving a certain way and they aren’t.  We don’t fool around with our data capture!

Personally I keep all my Custom Sets with the same card profile.  I keep manual the same as those too.  That way if I have an odd situation where I need to change, I can do so in manual mode for that shoot and then move back.

A quick overview of the settings you can pick from:

Menu H1 Card Slot Settings.

Standard: Exactly that…basically you pick one slot to use.

Autoswitch: When the slot you select becomes full, the second slot takes over recording.  Overflow.

Dual Independent Down: Saves to both card slots.  You can select what kind of files are saved to each card.  So RAW to one card and Small JPG to the other for example.  When one card becomes full, both cards stop and the camera says full regardless of card size.

Dual Independent Up: Same as above, but when one card becomes full, the other can continue.  Be mindful…if you card one was set to raw and becomes full… then only card two will continue recording.  If you only had small JPG going to card two…then all you will have is Small JPGs after the first card fills.  Until card two fills then you are full.

Dual Same Down: This is mirroring.  Whatever you save to the first card gets replicated on the second card.  When one is full, the second stops recording too regardless of card size.

Dual Same Up: This is mirroring just as above…except if one card fills and you still have space on the other, you can continue shooting…but there is no more mirroring.  And now you have one card that doesn’t match the other.  Make sure you keep track if this happens so you don’t lose pictures that didn’t get mirrored!


My personal recommendation for dual data:

Just shooting normally, use standard and one card.  If you do a lot of video and stills, use two cards and send video to one and stills to the other.  Use a fast card in slot one and send video there.  Keep slot two for your still images.

If you are on a critical shoot, or making work that really counts, and have the luxury of multiple cards…. then use two slots with Dual Same Down.  This is straight mirroring.  You have a backup no matter what happens.  Just make sure you use two memory cards large enough for your shoot, or have a second “pair” of cards.  Make sure you keep the cards organized.  You can use a think tank card walletand place pairs of cards next to each other so you that pairs are together.  Empty cards logo side out, and full cards rear side facing out.

If you are traveling this is my personal strategy for dual cards.  Have one BIG card in the second slot.  One that will cover your whole trip or most of it at least.  Then have a bunch of smaller cards for each day.  I change cards daily when I travel and lock the used ones in the hotel.  If I have a laptop I also back them up…if I don’t…then I just hope nothing happens to them!  With two slots, use Dual Same Down.  Each day change only your first card.  The smaller one.  Leave the second card, the large one, in the camera as a long running backup.  That way you have all your images on one huge card as a back up while all your smaller “day” cards are safe in the hotel or wherever your store them.  The concept is to ensure you can’t lose them, and nothing will happen if the camera is lost, stolen, or destroyed.  Either way you have the data somewhere.


FORMATTING CARDS: Just remember formatting is done separately on each card.  Do NOT confuse which card needs to be formatted.  In fact if you don’t trust yourself, remove both cards, format the correct one, and reinsert the other after.  Just saying!

Any other data strategies you use with dual cards?


16 responses on "E-M1 mkII Dual Card Slots Gotcha!"

  1. Thanks for this. I wouldn’t have thought to check card settings when I changed to a custom setting. I’m waiting for a month or so to see more evaluations before diving in. Until then, will keep reading your thoughts.

  2. Thanks for the hints. Do you know what is the impact in buffer overflow when in pro mode?

    My first card has 300MB/s write speed but the second one cannot be speedier that 95MB/s. Using both, means we have the slowest speed for clearing buffer, so using only one for pictures (I do not make video) could mean to have more number of pictures before getting buffer full.

    Is it like that?


    • I have not spent too much time with Pro Capture…but when using only a single card of the fastest speeds I have not been able to hit the buffer yet. It seems to keep up amazingly well even with repeated shooting in this mode. When using it with a second card that is also writing at the same time (redundancy) the buffer for the second card takes a lot longer obviously to write and clear. It seems the first card keeps up still independently. I think that is what is going on. I am not 100% sure. Again, not having yet hit the buffer limit, I can not speak to what happens at that point. I will definitely have to look into this further. So far I haven’t had any issues. In terms of the buffer of the shots when just holding down the shutter half way… that auto-clears and only cycles 14 shots I believe. Maybe someone with more experience in this form of shooting can chime in.

      • You’re not trying hard enough if you haven’t filled the buffer with ProCapture! Try setting ProCapture High and maximise the pre-frame setting to 35, then keep shooting at 60fps with no limit and you will fill the buffer very quickly, even with the fastest card in Slot 1.
        I’d like to know how the internal data bus works in the camera. My guess is that once the image has been captured on the sensor it is then goes to the processor. Next it is sent to the relevant storage, presumeably via a data bus. For the ProCapture feature to work there must be a buffer somewhere, which poses the question whether the buffer is before or after the processor. Before would obviate the need to buffer both JPG and RAW, after would mean the buffer capacity would result in being able to hold more shots if it is pre-processor.
        All this is a bit acedemic as I tend to limit the number of buffer frames simply because I find it a bore going through a lot of files!

  3. Thanks for the tip. Wouldn’t have thought of checking custom sets. I like your having re: traveling, too. Probably won’t need to do it that way but I do think it’s a neat idea.

  4. It so much easier just to use the master control panel on the LCD screen.

  5. I havE not been able to move through menus easily. I am new to Olympus menus and need help on how to move from one menu to the next. Is there help with changing menus. I understand changing in particular menus but cannot move from each menu to another menu. I am used to Canon menus which seem easier than Olympus menus. Thanks for any help that I can get.

  6. Hi Tony

    Many thanks for this. I was shooting in London yesterday and had some problems with my SD card 1 ( now fortunately resolved) ,however, was dismayed to find nada on my backup card 2! I was shooting manually and had not set it to ‘Dual Same Down’ for M, only A. This is now my default setting for ALL modes, so a BIG thank you for pointing this out.
    I have just looked at the Oly manual p 54 and there is no mention of it.

  7. Tony (Eagle Eye), How on earth did you find this out and where is it in the manual?
    I had set up for mirror backup- dual same down, but this was in aperture mode and I shoot in manual! Recently Card 1 had some problems, so I just put card 2 into my reader, only to find nothing! Finally I sorted card 1 and the read your article. All I can say, is a big thanks you and well done!! I have set mirror backup for all shooting modes. ‘Card Setup” icon is displayed on the bottom right of the screen, just next to the, ‘number of storable still pictures’. I have now confirmed this icon assigned to all shooting modes.

    Many thanks again

    • Shooting for a living in a commercial environment sticks me in some interesting situations where I have to use a lot of different functions of the camera. The olympus has been great because I can do so much with it and fine tune it to each situation. You just end up hitting these odd roadblocks when you least expect them and most need them. Trial by fire i guess.

  8. Thanks for great tip on using dual card slots.

    One thing is bugging me which I cannot figure out.

    How can I have the camera replicate the video files to be saved on both cards. The JPGs and ORFs replicate fine… but the .MOV files only get saved to one card.

    As I am mainly doing video it leaves me with little redundancy.

    • Yes good observation. The camera doesn’t allow for this yet. I am going to add this to my feature request. I hadn’t noticed this on the camera yet. A work around is by going to Menu – Playback – Copy All – 1 to 2. This copies everything from your card slot 1 to your card slot 2. It is a manual way to make a backup. However…If you do this incrementally…it will re-copy everything with new names and duplicate the files. So it’s easier just to do it once. Again, not a working redundancy …but better than nothing at the moment.

  9. (Late) thanks for this incredibly useful post.
    The manual is really deficient on this topic.

    My observations regarding speed (= clearing of the buffer = blocked camera):
    – The real slowdown is writing 2 files (e.g. RAW+LF) instead of LF only.
    – If you write 2 files, the setup makes only minor differences: writing on two cards is
    a bit slower than writing on the same cards, but not much.
    – If you write 2 files, card setup and speed of card 1 matter.
    (I compared Lexar 1000x with Lexar 2000x, both 64GB, in slot 1, counting the
    blinks of the card writing symbol in the upper left corner, admittedly not a very
    scientific way of measuring, but the camera is blocked during this process. The second
    card was constant: 95MB/s SanDisk).
    I tried burst-H limited to 25 frames and ProCap-L 14 pre-frames + quick shutter press.
    With burst-H limited to 25 frames:
    1. No differences if you write only LF/JPG to card 1 -> no need to buy the faster card.
    2. RAW+LF->1: 3,3 times longer with 1000x – 2,5 times longer with 2000x
    3. RAW->1 + LF->2: 3,2 times longer with 1000x – 2,8 times longer with 2000x
    ProCap-L 14 pre-frames + quick shutter press:
    1. No differences if you write only LF/JPG to card 1 -> no need to buy the faster card.
    2. RAW+LF->1: 2,9 times longer with 1000x – 2,1 times longer with 2000x
    3. RAW->1 + LF->2: 2,4 times longer with 1000x – 2,1 times longer with 2000x

    Concerning Tony’s remarks on dual card configuration just 2 additions:
    – If you split RAW->1 + LF->2:
    – both files will have identical names (good)
    – in order to get a decent preview you have to set the preview card to slot 2 (menu H1)
    – the display/finder will only display the picture quality selected for the preview card
    (e.g. “RAW” only if you select card 1 or “LF” only if you select card 2). This confuses me.
    – The Olympus App O.I.Share (tested on iOS) only accesses slot 1, reagardless of the
    setting in menu H1. So you have to put card 2 in slot 1 to transfer the JPEGs.

    • Excellent contribution, much appreciated. Also, thank you for the mention of OIShare only reading slot 1… that is a good thing to keep in mind. I often use OIShare for grabbing shots to text or email people while in the field. Thanks!

  10. Just found your blog. Very useful info. Please keep it up. Thanks a lot!

  11. Thanks for this very critical tip, I am setting my OMD EM1 Mark II and when I go to Save Settings I only get
    two options Standard or Dual Independent up arrow none of the other options are available. I only have a card in Slot 1 does than effect the programming as I would like to use Dual Indenpendent down but have no option for that. I have tried all type of modes and it does not matter. Any pointers to remedy this would be appreciated.

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