Raw recording and sd card

Started by PublioAdriano, October 25, 2015, 09:49:56 PM

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PublioAdriano

Hi everybody, i have a Canon 70D with nightly buildon and i'm try to make some RAW videoattempt.
Obviously the problem is in my low writing speed SD.
I'm lookiing for a good SD card and i have seen this http://www.amazon.co.uk/Gobe-Magic-104MB-Write-Memory/dp/B00VLCTWXC on Amazon.
My doubt is if this SDXC is supported by my reflex.
If yesm it will write a that speed?

Walter Schulz

SDXC is supported. Read your manual, please. You will find this info in the section explaining how to insert and remove cards.

And your cam will for sure not support card's maximum write speed. SD-card interface in 70D is limited to about 41 MByte/s (write).
According to CameraMemorySpeed.com this card is a rebranded Sony 95 MByte/s card. http://www.cameramemoryspeed.com/reviews/sd-cards/gobe-magic-104mbs-64gb-sdxc-memory-card/
And performance in EOS 6D/70D seems not on par with some other cards.

PublioAdriano

So buiyng this SDXC doesn't solve the frame skipping problem?

Walter Schulz

Answer: No. Or yes. Depends on the resolution/frame rate you want to achieve.
See http://rbrune.github.io/mlraw/
And use ExFAT file system.

PublioAdriano

Thank you for the answers, what do you mean with ExFat file system? I can't understand the link you posted!

Walter Schulz

Rbrune's web page will help you to determine RAW/MLV resolution/aspect ratio and frame rate supported/required by your camera/memory combination.
ExFAT is a file system you have to apply to your card by formatting it. Depending on card's size the cam will apply ExFAT. Or not. You can check card's properties and therefore card's file system. If it is FAT32 there is no chance to get 720p24 working and you have to use a cardreader to reformat the card with ExFAT. You have to reinstall ML then, of course.

PublioAdriano

I'm trying to use the link you psoted, what is the Sampling mode?

Walter Schulz

3x3 is default RAW video mode = Line skipping for 70D: Active area is sensor area but only every 3rd line is used. That's why Canon's H.264 output is not that sharp/detailed. Side effect: Rather strong aliasing/moiré. You may google for VAF filter.
1x1 is RAW crop mode = Active area is not whole sensor area but only a cropped rectangle. And every line is used: Aliasing/moiré not a big issue. Side effect: Lens' field of view is reduced.