Spanning

[beauchampy]

I do apologise if a thread on this already exists, I did do some searching, but couldn't really find what I was looking for..

I have seen some users getting incredible data rates on their MKIII's using spanning. For example I came across this video yesterday. The user claims to get almost 30 seconds at 2560 x 1090

I'd like to experiment with 2.5k RAW at this resolution - currently I have a couple of 32gb Lexar 1000x compact flash cards, I'm looking for a SD card to complement for spanning. I did see this Komputerbay one today for a good price - http://www.hotukdeals.com/deals/komputerbay-128gb-sdxc-secure-digital-extended-capacity-speed-class-10-600x-uhs-1924572

So, some questions..

1. What is the max write speed on the SD card controller on the 5D III? Is a 90mb write (same at the Komputerbay card above) already over the limit? Or can I look for something even higher?

2. How are these spanned files correctly joined together to create a DNG sequence after recording?

3. Have you been using spanning to get high data rates? What have you found compared to recording normal MLV to a single CF card?

Many thanks to everyone!

[beauchampy]

No one experimenting with spanning? 

[Midphase]

Not really.

Here are a couple of facts:

1. on the 5D3, the maximum non-crop resolution is 1920x1288. Any higher horizontal resolution requires to go into crop mode which has its own issues and it's really not practical for more high end productions.

2. Spanning adds an extra layer of uncertainty to the data which I think many people would prefer not to deal with. There was talk about spanning when audio was not available, but nowadays with mlv's both audio and video get recorded quite well on a single CF card.

3. Komputerbay has released 1066X 64Gb cards which appear to be able to give extra speed so that even 30fps at 1920x1288 is perhaps doable.

4. Without spanning, I have been able to record (on a well specced CF card) at 2.5K raw (at 2.35:1), so spanning to achieve those resolutions might not necessarily even be required.

[Audionut]

1.  20MB/s.  Faster cards are always better, regardless of the slot speed IMO.
2.  Automatically
3.  I have a 16GB Lexar 1000x, and for me, this card is not quite able to record 1920x1080 consistently.  Sometimes I might get 1000 frames, or only 200 frames.
With card spanning on, I can record until card full.


I'd be interested in hearing how many people actually use spanning.  It was a rather popular feature request.

[Midphase]

3.  I have a 16GB Lexar 1000x, and for me, this card is not quite able to record 1920x1080 consistently.  Sometimes I might get 1000 frames, or only 200 frames.

I really hate how inconsistent CF card speeds seem to be. On most of my Komputerbay 1000X I can sustain 1920x1288 in .raw, but .mlv with audio means just 1080p for me.

I've been wondering if the new Komputerbay 1066X would be able to sustain 1920x1288 with sound in .mlv?

[Audionut]

I think the biggest problem, is that we are always trying to push them to the limit, on a system that otherwise wasn't designed for it.  Having card spanning on, removes some of that inconsistency, and allows to record at slightly higher res also.

I remember discovering after my purchase, that the 32GB variety was faster. 

Ted might know about the 1066x cards, I think he is always testing Komputerbay cards.

[swinxx]

@midphase:

i record mlv´s with 1920x1290 (not really continuous but 30sec are no problem..) with a komputerbay 1000x 64gb card and run the latest  ml firmware for my 5d mk3 in the nightly builts (it is from 23 may 14)..(spanning enabled) isn´t that great... i had no green tinted raw files with the latest software.. and the most tools like rawmagic and mlrawviewer handle spanned files perfectly.
 
i wonder if nothing happened since 23.may for 5dmk3 and 1.2.3 firmware? that is really unusual caus i think since the beginning of 2013 it is the longest deadlock i can remember.. perhaps its all so stable and they are working on further improvements which are included in the nightlys when they are rock solid
i wonder if the sensor information from the different canon is all the same? cause they have different sensors? haven´t they?
greets.

[jgerstel]

Hi, this is a blacklevel issue. You can fix it with exiftool and set Blacklevel to 2047, example:

exiftool -Blacklevel=2047 *.dng

[jose_ugs]

I'm still using spanning, exactly for that same reason: you need a bit of "support" where even @ 1080p the inconsistency kicks in...

#1 I've also noticed better results with faster SD cards, regardless of 5DM3's slot bandwidth

1.  20MB/s.  Faster cards are always better, regardless of the slot speed IMO.
2.  Automatically
3.  I have a 16GB Lexar 1000x, and for me, this card is not quite able to record 1920x1080 consistently.  Sometimes I might get 1000 frames, or only 200 frames.
With card spanning on, I can record until card full.


I'd be interested in hearing how many people actually use spanning.  It was a rather popular feature request.

[anDyIII]

Now I'm testing with new Komputerbay 1066x 128GB CF (it should be the same of 1000x) and I'm comparing the Transcend 600x SD with the Sandisk Extreme 45 MB/s for Card Spanning.
I'll let you know the results.

[KMikhail]

Once I got 1066x 64GB Lexar, 1080P @24fps became a no-brainer, always works. Without spanning, or with spanning (64GB, 95mb/s SanDisk). Spanning will just allows longer recordings, since it is split between two cards, where CF is limiting.

However, on 1.2.3 it can't sustain 1080P @30fps, only about 30+ seconds with hack. Using spanning has very little effect, just like with tests: it adds just a few mbs. apparently there is a bottle neck for a total band. I'm sure earlier firmware should really help, since I'm short just of a few mbs.

MLV+sound.