Blackmagic Forum

So that was unexpected, as my camera has never suffered from dropped frames before.

One of the shots had multiple missing frames, which open as solid red frames.

The camera is Ursa Mini 4,6K, with a Lexar X3600 256GB card, on full RAW, on full 4608X2592 resolution at 60 FPS.

Of course the "stop rec if card drops frame" option was OFF, but that does not fix the problem.

Very rarely I do shoot 60fps 4.6K RAW, but is it something normal to be aware of?

Here is a part from the shot:

http://www.newactorsstudio.com/storage/ ... FRAMES.rar

60fps RAW should normally be recorded with writing onto 2 cards at the same time, because 1 card can be too slow for this amount of data.

Is there a CFAST card on the market, that is faster than the Lexar X3600 ?

Here is my further finding.


On a Lexar X3600 at 4.6K

1. Full RAW:

60 FPS - drops frame in about 7-8 seconds.
50 FPS - drops frame in about 10-12 seconds.
40 FPS - drops frame in about 30 seconds.

2. 3:1 RAW - no problem at all

3. 4:1 RAW - no problem at all

Emilian Dechev wrote:So that was unexpected, as my camera has never suffered from dropped frames before.

One of the shots had multiple missing frames, which open as solid red frames.

The camera is Ursa Mini 4,6K, with a Lexar X3600 256GB card, on full RAW, on full 4608X2592 resolution at 60 FPS.

Of course the "stop rec if card drops frame" option was OFF, but that does not fix the problem.

Very rarely I do shoot 60fps 4.6K RAW, but is it something normal to be aware of?

Here is a part from the shot:

http://www.newactorsstudio.com/storage/ ... FRAMES.rar

Read page 26 of the URSA Mini Manual.

Emilian Dechev wrote:Is there a CFAST card on the market, that is faster than the Lexar X3600 ?

Here is my further finding.


On a Lexar X3600 at 4.6K

1. Full RAW:

60 FPS - drops frame in about 7-8 seconds.
50 FPS - drops frame in about 10-12 seconds.
40 FPS - drops frame in about 30 seconds.

2. 3:1 RAW - no problem at all

3. 4:1 RAW - no problem at all

CFast 2.0 uses the SATA 3 standard, which has a theoretical limit of 6 GBit/s and netto 4.8GBit/s or 600 MB/s (-20% protocol overhead).

CinemaDNG 4.6k full RAW data rates:
30 fps .... 513MB/s
40 fps .... 684MB/s
50 fps .... 855MB/s
60 fps .... 1026MB/s

CinemaDNG 4.6k RAW 3:1 data rates:
30 fps .... 180 MB/s
40 fps .... 240 MB/s
50 fps .... 300 MB/s
60 fps .... 360 MB/s

CinemaDNG 4.6k RAW 4:1 data rates:
30 fps .... 135 MB/s
40 fps .... 180 MB/s
50 fps .... 225 MB/s
60 fps .... 270 MB/s

So you see there is no possibility to use just one card when recording >30 fps full RAW.

Yes that makes sense, thanks!

Hi,

I've run several tests with different Cfast cards and had the best results with a 256gb x3600 Lexar.
It has recorded 4.6K lossless RAW 50 fps on my UMP without dropping any frame. I've stopped recording after 4 minutes.
60 fps 4.6K Lossless RAW stops after 15.18 seconds.

Had good (but not as good as Lexar's) results with a SANDISK Extreme Pro 515MB/s.

Had weaker performances with both Wise and Egodisk cards.

Will post my results ASAP.

The only media that was able to record flawlessly 4.6K lossless RAW 60 fps is a Samsung 850 Pro through a Cfast to SSD solution.
I've stopped recording after 12 minutes.