CFast or external SSD

Hi, I'm waiting for my Pocket 4K to arrive and I have a doubt.

Is it any better to use an external SSD (like a Samsung T5) instead of the internal CFast card (3400x Wise CF card) apart from the price difference? I will be recording RAW at full resolution and max FPS possible.

I wouldn't shoot (lossless) uncompressed 4k 60 fps, you will get dropped frames with both USB SSD as with CFast.

Thanks for your reply.

If there is going to be a lost-frames problem, why would they offer the possibility of shooting that way? And if so, do you know what is the (real) maximum this camera can handle?

Hi, I'm waiting for my Pocket 4K to arrive and I have a doubt.

Is it any better to use an external SSD (like a Samsung T5) instead of the internal CFast card (3400x Wise CF card) apart from the price difference? I will be recording RAW at full resolution and max FPS possible.

Wise Advanced makes Portable SSD and certified for Blackmagic Pocket Cinema Camera 4K.

Thanks for your reply.

If there is going to be a lost-frames problem, why would they offer the possibility of shooting that way? And if so, do you know what is the (real) maximum this camera can handle?

When you have a static background the CDNG files will be smaller (CDNG is lossless compressed).
When the USB-C is gen2 it should be possible to go all the way.

Ok, so I can assume from all your answers that an external SSD like the Wise Portable SSD for Blackmagic Pocket 4K Cinema or the Samsung T5 (both connected to the camera with USB-C 2.0 will "swallow" whatever the camera can shoot without clogging the buffer? Is this correct?

Ok, so I can assume from all your answers that an external SSD like the Wise Portable SSD for Blackmagic Pocket 4K Cinema or the Samsung T5 (both connected to the camera with USB-C 2.0 will "swallow" whatever the camera can shoot without clogging the buffer? Is this correct?

No, because I don't know what generation the USB-C on the camera is.

When it's USB3.1 gen 2 you will need a portable SSD with a NVMe SSD inside and a USB-controller that can handle 10 Gb/s.

When not, it won't work the way you want.

Ok, so I can assume from all your answers that an external SSD like the Wise Portable SSD for Blackmagic Pocket 4K Cinema or the Samsung T5 (both connected to the camera with USB-C 2.0 will "swallow" whatever the camera can shoot without clogging the buffer? Is this correct?

No, because I don't know what generation the USB-C on the camera is.

When it's USB3.1 gen 2 you will need a portable SSD with a NVMe SSD inside and a USB-controller that can handle 10 Gb/s.

When not, it won't work the way you want.

The camera is the Pocket 4K Cinema released days ago. It's supposed to have the latest USB-C port generation...

It's probably a USB 3.1 gen 1 port with a gross speed of about 4.8 Gbit/s ~ 480 MByte/s best case scenario. So forget the 4k 60 fps CNDG lossless RAW.

It's probably a USB 3.1 gen 1 port with a gross speed of about 4.8 Gbit/s ~ 480 MByte/s best case scenario. So forget the 4k 60 fps CNDG lossless RAW.

B&H confirms that it's a second generation USB-C port but they are not sure if it will be able to handle all the work. They will confirm by email (faster than Blackmagic will) I'll post their answer for others to know.

Thank you all

Carlos, if B&H Photo is talking about the port on the Wise Portable SSD and the Samsung T5, they are correct the device is USB 3.1 gen 2. They may have misinterpreted your question. BMD has categorically stated from day one that the USB Type C port on the BMPCC4K is 3.0 or 3.1 gen 1. Their published guidelines say only a maximum DCI 4K CinemaDNG raw 3:1 60fps is supported. There’s no support in the BMPCC4K for interleaving frames with the SSD/SDXC cards that would enable lossless raw 60 fps.

If it’s really a USB 3.1 gen 2 port, then BMD has quietly upgraded the production product since NAB 2018 or IBC 2018. However I know Wise confirmed their card is limited to recording DCI 4K CinemaDNG raw 3:1 60fps on cards that are rated to write up to 520MB/s and actually tested on their own BMPCC4K. And I recall someone saying they couldn’t get faster than that using the Samsung T5.

The limiting factor may be the SATA III interface whether or not the ports are gen 2 or not.

Sent from my iPhone using Tapatalk

Carlos, if B&H Photo is talking about the port on the Wise Portable SSD and the Samsung T5, they are correct the device is USB 3.1 gen 2. They may have misinterpreted your question. BMD has categorically stated from day one that the USB Type C port on the BMPCC4K is 3.0 or 3.1 gen 1. Their published guidelines say only a maximum DCI 4K CinemaDNG raw 3:1 60fps is supported. There’s no support in the BMPCC4K for interleaving frames with the SSD/SDXC cards that would enable lossless raw 60 fps.

If it’s really a USB 3.1 gen 2 port, then BMD has quietly upgraded the production product since NAB 2018 or IBC 2018. However I know Wise confirmed their card is limited to recording DCI 4K CinemaDNG raw 3:1 60fps on cards that are rated to write up to 520MB/s and actually tested on their own BMPCC4K. And I recall someone saying they couldn’t get faster than that using the Samsung T5.

The limiting factor may be the SATA III interface whether or not the ports are gen 2 or not.

Sent from my iPhone using Tapatalk

I did have the SATA III limit in mind but the technician at B&H seemed very confident. Anyway he is asking BMD directly and will email me back with their response.
Anyway, if no one has a 550Mb/s CFast or SSD there's no point in asking.

Carlos, if B&H Photo is talking about the port on the Wise Portable SSD and the Samsung T5, they are correct the device is USB 3.1 gen 2. They may have misinterpreted your question. BMD has categorically stated from day one that the USB Type C port on the BMPCC4K is 3.0 or 3.1 gen 1. Their published guidelines say only a maximum DCI 4K CinemaDNG raw 3:1 60fps is supported. There’s no support in the BMPCC4K for interleaving frames with the SSD/SDXC cards that would enable lossless raw 60 fps.

If it’s really a USB 3.1 gen 2 port, then BMD has quietly upgraded the production product since NAB 2018 or IBC 2018. However I know Wise confirmed their card is limited to recording DCI 4K CinemaDNG raw 3:1 60fps on cards that are rated to write up to 520MB/s and actually tested on their own BMPCC4K. And I recall someone saying they couldn’t get faster than that using the Samsung T5.

The limiting factor may be the SATA III interface whether or not the ports are gen 2 or not.

Sent from my iPhone using Tapatalk

I did have the SATA III limit in mind but the technician at B&H seemed very confident. Anyway he is asking BMD directly and will email me back with their response.
Anyway, if no one has a 550Mb/s CFast or SSD there's no point in asking.

Don't you *really* mean 550MB/sec?
That lower-case "b" you're using is for "bits" whereas Bytes (much larger, by a multiple of 8) are signified by the uppercase "B".
[Re]Pete

Carlos, if B&H Photo is talking about the port on the Wise Portable SSD and the Samsung T5, they are correct the device is USB 3.1 gen 2. They may have misinterpreted your question. BMD has categorically stated from day one that the USB Type C port on the BMPCC4K is 3.0 or 3.1 gen 1. Their published guidelines say only a maximum DCI 4K CinemaDNG raw 3:1 60fps is supported. There’s no support in the BMPCC4K for interleaving frames with the SSD/SDXC cards that would enable lossless raw 60 fps.

If it’s really a USB 3.1 gen 2 port, then BMD has quietly upgraded the production product since NAB 2018 or IBC 2018. However I know Wise confirmed their card is limited to recording DCI 4K CinemaDNG raw 3:1 60fps on cards that are rated to write up to 520MB/s and actually tested on their own BMPCC4K. And I recall someone saying they couldn’t get faster than that using the Samsung T5.

The limiting factor may be the SATA III interface whether or not the ports are gen 2 or not.

Sent from my iPhone using Tapatalk

I did have the SATA III limit in mind but the technician at B&H seemed very confident. Anyway he is asking BMD directly and will email me back with their response.
Anyway, if no one has a 550Mb/s CFast or SSD there's no point in asking.

Don't you *really* mean 550MB/sec?
That lower-case "b" you're using is for "bits" whereas Bytes (much larger, by a multiple of 8) are signified by the uppercase "B".
[Re]Pete

Yes, of course, I mistyped.

Ok, so this is BMD's answer:

"Our list of certified USB-C drives only support 4K DCI Lossless RAW up to
30 fps and 4K DCI 3:1 RAW up to 60 fps. Both the Samsung Portable SSD T5
and WISE Portable SSDs are listed to support both of those formats."

End of the story.


Thank you all for your help.

Ok, so this is BMD's answer:

"Our list of certified USB-C drives only support 4K DCI Lossless RAW up to
30 fps and 4K DCI 3:1 RAW up to 60 fps. Both the Samsung Portable SSD T5
and WISE Portable SSDs are listed to support both of those formats."

End of the story.

Thank you all for your help.

Hi Carlos!
I'm building cfast to ssd adapters for ursa and canon c200 cameras and was curious if I can record lossless 4K DCI at 60fps. So I did a test:
-Samsung 850 evo 1tb msata inside an 2.5" msata-sata enclosure
-cfast to sata cable/adapter
-usb to powerSATA cable to power the ssd from pc. Have no power-banks in house at this moment.

Guess what! I was able to record 29min wit zero droped frames!