[Leica] SD Card Questions, M(240) Gearhead Edition

[red735i at verizon.net (Frank Filippone)]

Of course, I use an M9...  but here is my cut on all of this....

a) the manufacturers use the memory chips they can get, cheap, on SD cards.
More speed = more cost = more cost to you.  So they tend not to do anything
that interferes with their profit picture.

b) they change chips because they got a deal on the price....  As long as
the card made MINUIMUM spec, they "only" care about the price

c) you have no idea of what chips are inside nor the specs on those chips.

d) The speed ratings on SD cards refer to the READ speed, not the WRITE
speed.  ( you can look this up, but it is true)

e) Some faster read devices are also faster on the write, but this is not
necessarily so....  ( experimentation in YOUR device is required to see if
it makes any difference)

f) while it has been retail true that some 8GB cards were slower than their
succeeding 16GB cards, that was probably a figment of the change in the chip
technology, but the branded name on the card stayed the same....  ie, it
never really made a difference if it were a 8, 16 or 32 GB card,,, it was
what was inside that made a difference and they never told you when they
made a change!....

g) Sandisk make their own IC memory chips.  Does that means that if you buy
a Sandisk SD card, they use Sandisk ICs inside?  No.  ( ditto every other SD
card.  You do not know what is inside) 

Sandisk helped figure out a problem that Leica had with Sandisk SD cards in
the M8 (?? Not sure my memory is right about the model, but irrelevant, that
is where their relationship started). I think now, they are BFFs.  ( as long
as there is mutually no problems)

Finally my experiences in the M9

I have cards going back to class 4.
I have cards that are class U1.

In MY M9, the Class U1 cards DID write faster than the class 4.  But it was
not really a great difference.  ( I did a burst and timed the burst speed
transfer).  Upon reading , the faster cards were faster, but that was in my
computer and card reader, not the camera.  Relevance to write speed in the
M(240) ?  None.
In My Sony A7, there was a remarkable difference in the write speeds.

Is it that Leica is writing their Firmware different from Sony ( with
significantly more experience and expertise?)  Yes, in part.

Is the faster card  helping on its own?  Yes, in part, but I think it is the
first reason that has more weight.....

Bottom line... buy a Class U1 card, test it to see what you bought in
practical terms, and be happy.. recently they are running less than $0.50 a
GB when on sale.  ( we are talking about $20 per card times 2 in a camera
that cost $7K  Is it really relevant to your next Leica body or lens
purchase? Or your choice in Scotch?  Or Craft Brew?)

What capacity?  Whatever is on sale, keeping in mind that with a M(240)
there are raw file sizes of around 24MB = 40 shots per GB, times the GB
rating of your card.... 32GB would have 1200 odd images per card... 16GB is
600.... a couple ( always buy 2 in case one card dies without reason) of
cards is a whole lot......  
So does it really matter if your daily shoot is 100-200 images....  No.
ZGpoing away for a week?  But 3... month?  Buy a mess of cards or buy less
and a WD Wireless HDD with a built in SD Card Reader (or Digital Foci, or
Sanho, or whatever brand floats your boat), which may cost you appreciably
more than the extra cards will cost, but may give you peace of mind with
backups.....

For those that might wonder, I was educated as an Electrical Engineer.  I
was in the IC industry for 25 years. This is an issue about specs, and
specmanship. 

Frank Filippone
Red735i at verizon.net


I see that Leica suggests Sandisk Ultra or Extreme Class 10 SD cards with
speeds >30 MB/s.  http://content.abt.com/documents/54249/LEICAM_FAQ.pdf

There are some folks on another well known Leica forum who say the speed -
both waking and shooting - is noticeably better with the latest and fastest
cards, which have maximum speeds of 95 MB/s.  I have also seen posters in
various forii say they get faster speeds with 16GB cards than they do with
32GB cards.

I'm just curious to know if any LUGers have discerned - when shooting with
an M (240) or an M-P (240) - noticeably faster speeds or any other
_noticeable_  advantage to using 60 MB/s versus 95 MB/s SD cards, and also
any _noticeable_ speed difference when using 16GB, 32GB or larger cards.

Thanks,

--Bob