Advice for SD cards

[thickglass]

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Hi guys, SL manual does not say anything particular about SD cards.  What is the best choice? 

[ramarren]

There have been a few threads on this topic, if you care to use the Search function. 

 

I've used two kinds of cards with the SL: Sandisk Extreme Pro in 32G and 64G capacities, and Lexar 1000x Pro 128G. They are both (theoretically) capable of being written to faster than the SL can write (either stills or 4K video), so they're not slowing anything down. And I've had zero problems with either of them. 

 

The small bit of advice that I've got beyond that is to use the SD Card Formatter to do a low-level format on any new card you're going to use once. Doing that seems to improve the SL's startup time. Since I've had the SL, I've not formatted any of the cards either ... I just use them until they get full, which takes a while! ... and then replace them with a new one since prices for these things are now so very very low. (I remember when a slow-ish 1G SD card cost four times what the current ultra-fast 128G SDXC card costs!)

[RoySmith]

I noticed a change in the SL's Technical Data sheet between the release info in October 2015 which can be read here, and the current Technical Data on Leica's webpage which is dated Sept 2016.

The first Technical Data sheet stated: "SD 1 slot (UHS II) with maximum writing speed 100 MB/s, SD 2 slot (UHS I) with maximum writing speed 30 MB/s", whereas the current Technical Data sheet lists the compatible SD cards, but does not refer to the speed of writing. This made me curious as to how fast slot 1 could write data to SD cards. To test this my method was to insert a fresh SD Card, format it in camera. The camera was set on Continuous fast Shutter - 11 fps , manual, auto iso, 1 /100 shutter speed - using  a SEM 18mm. The camera has firmware version 2.1. I then held down the shutter, until the shutter paused. At this point, assuming the buffer was full, I let go of the shutter and started a timer. I stopped the timer when the red light stopped flashing assuming the files in the buffer were finished transferring to the SD card. I repeated this twice with each of 3 SD Cards, and averaged the write time which was within 1 second for the 2 trials with each card. The cards were all in slot 1 and slot 2 was empty. The camera was set to save DNG files only.

My results were:

Sandisk Extreme Pro UHS-II 64 GB   280 MB/sec; 31 files (44.2 MB each) in 44.96 seconds = 30.48 MB/sec

Sandisk Extreme Pro UHS-I 64 GB      95 MB/sec; 36 files (44.2 MB each) in  53.93 seconds = 29.51 MB/sec

Lexar Professional 633X UHS-I 32 GB 95 MB/sec; 37 files (44.2 MB each) in 60.54 seconds = 27.01 MB/sec

 

​Thus the writing speed I measured was no where near the 100 MB/sec specified originally, and varied very little between the UHS-I cards and the UHS-II card.

Was my method of calculating write speed flawed in some way ?  Perhaps write speeds when doing video is faster - I did not try to measure that - as I only do still photography.

Currently for still photography I see little reason to buy the newer UHS-II cards - although I only tested the one.

 

Roy

[steppenw0lf]

No, it is very similar to the results Ramarren measured half a year ago (or even more, please use the search function).

But these are measured values, which is not the same as the speed given by the manufacturer, which is more of a "best theoretically possible" approach.

So I think theoretically the camera is faster, but with the current files it is not possible to reach that maximum.

So in reality for photography UHS-I cards should be fast enough. While for 4k filming there is no way around UHS-II cards (which by the way offer by definition a minimal write speed of 30 MB/s - just enough for 4k video).

 

In reality the numbers that Sandisk, Lexar and others write onto their cards are unrealistic. And very imprecise - just think about the fact that they give usually only one number, but that in reality read- and write-speeds are typically quite different (often by a factor of three or more).

And the maximum speeds can only be reached when VERY big files are read/written. (several Gigabytes in one piece). For smaller files there is always the problem that directory data also has to be updated for each file, interrupting the ideal flow.

 

Testing the cards in a dedicated reader gives better results, but they are still far away from the theoretical numbers written on the cards. (You could definitely say that they are simply telling lies.   )

[leica1215]

I noticed a change in the SL's Technical Data sheet between the release info in October 2015 which can be read here, and the current Technical Data on Leica's webpage which is dated Sept 2016.

The first Technical Data sheet stated: "SD 1 slot (UHS II) with maximum writing speed 100 MB/s, SD 2 slot (UHS I) with maximum writing speed 30 MB/s", whereas the current Technical Data sheet lists the compatible SD cards, but does not refer to the speed of writing. This made me curious as to how fast slot 1 could write data to SD cards. To test this my method was to insert a fresh SD Card, format it in camera. The camera was set on Continuous fast Shutter - 11 fps , manual, auto iso, 1 /100 shutter speed - using a SEM 18mm. The camera has firmware version 2.1. I then held down the shutter, until the shutter paused. At this point, assuming the buffer was full, I let go of the shutter and started a timer. I stopped the timer when the red light stopped flashing assuming the files in the buffer were finished transferring to the SD card. I repeated this twice with each of 3 SD Cards, and averaged the write time which was within 1 second for the 2 trials with each card. The cards were all in slot 1 and slot 2 was empty. The camera was set to save DNG files only.

My results were:

Sandisk Extreme Pro UHS-II 64 GB 280 MB/sec; 31 files (44.2 MB each) in 44.96 seconds = 30.48 MB/sec

Sandisk Extreme Pro UHS-I 64 GB 95 MB/sec; 36 files (44.2 MB each) in 53.93 seconds = 29.51 MB/sec

Lexar Professional 633X UHS-I 32 GB 95 MB/sec; 37 files (44.2 MB each) in 60.54 seconds = 27.01 MB/sec

Roy

Anyway, by using the UHS-II we are still fast ahead of the other two by 9 seconds, I think is quite noticeable, the differences between iPhone 6 to iphone 7 in openings app, just like 1.5 or 3 seconds faster, I still feel it. Thanks for sharing

 

 

 

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[250swb]

I use a 64gb Extreme Pro, but I did have a problem with it, or the camera, in the first few days. It came straight from my M246 and was formatted in the SL and after a while 'not written to card' (or similar) started to appear on the LCD. So I went back to basic's and used SD Formatter to completely overwrite the card and it has been working very well since then, to delete images I just format the card in the SL as usual. So was it the card, or is the SL sensitive to any junk on the card that doesn't normally affect other cameras? Either way as SD Formatter is free it's probably worth using even for a brand new card.

[RoySmith]

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I use a 64gb Extreme Pro, but I did have a problem with it, or the camera, in the first few days. It came straight from my M246 and was formatted in the SL and after a while 'not written to card' (or similar) started to appear on the LCD. So I went back to basic's and used SD Formatter to completely overwrite the card and it has been working very well since then, to delete images I just format the card in the SL as usual. So was it the card, or is the SL sensitive to any junk on the card that doesn't normally affect other cameras? Either way as SD Formatter is free it's probably worth using even for a brand new card.

I haven't had that happen yet. I tried using SD Formatter on my Mac Pro 2009 with a 64 GB UHS-II card and it formatted it at 32 GB. When I reformatted it in the camera it went back to 64 GB. I guess the card reader did not work with UHS-II cards.

 

 

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[steppenw0lf]

Currently prices (for SDXC cards) are too high for me, so I want to reuse my cards (which I usually avoid).

I agree that formatting with the SD formatter is probably useful for a brand new card.

But for a used card, is it also necessary ? I would rather simply remove the folders the SL created (only 3 or 4 for a 128 GB card).

How do others recycle their cards ? Always a full format ? Any experiences (good or bad) with removing the folders ?

[jrp]

I just reformat in camera.

 

The main reason for buying fast cards is the transfer speed onto a (recent) PC / Mac, rather than shooting speed, on the SL