SSDs & SD cards for CinemaDNG with the Sigma fp (L)
The Sigma fp and fp L do not only stand out with their unique form factor. The ability to record RAW video internally in CinemaDNG format is also something you don't see every day. But CinemaDNG and Sigma's fp cameras are quite demanding.
If you want to use the internal SD card slot, a maximum of Full HD with 12 bits per channel and 59.94 fps is possible. In 4K Ultra HD, you even have to settle for a maximum of 25 fps and 8 bit color depth, which hardly offer more editing possibilities than recordings in compressed MOV. Even these seemingly low requirements are at the edge of what is technically possible with UHS-II SD cards. Thus, just five SD memory cards met the highest requirements in our tests.
Those who want to fully exploit the capabilities of the Sigma fp (L) have another, even better option: External SSDs. Both cameras feature a USB-C port that can address USB type C SSDs. In addition to the significantly higher speed, there is also an immense price advantage of up to a factor of 10 – compared to SD memory cards with an UHS-II interface.
But: Sigma's fp cameras are extremely picky and only work with an exquisite range of external SSDs. The camera confirms the use of other USB-C SSDs with various error messages, usually the connection just fails. Sigma also provides an official compatibility list for SSDs.
How should I interpret the max. bit-rate?
We have measured the maximum possible write speed for video recordings. Since the Sigma fp (L) aborts video recordings after only a few seconds if the storage media is too slow, there is not much more to do than trying again and again, until you reach a stable maximum. We test the following CinemaDNG settings in descending order until a format can be recorded without interruption for a longer period of time:
- 2160p30 12 bit (3.020 Mbit/s; Nur SSDs)
- 2160p25 8 bit (1.670 Mbit/s)
- 1080p60 10 bit (1.280 Mbit/s)
- 1080p50 10 bit (1.060 Mbit/s)
- 1080p50 8 bit (850 Mbit/s)
- 1080p30 10 bit (640 Mbit/s)
Consequently, the maximum possible speeds for SSDs (3,020 MBit/s) and SD memory cards (1,670 MBit/s) are capped on the one hand and can only be tested in larger steps on the other.