Does it matter which V90 card you use if camera doesn't specify the actual write speed required?

[erotavlas]

Certain modes like 4K 120fps require V90 SD card, however the manual for my camera (sony a6700) only specifies which recording modes require V90 cards, but it doesn't actually specify what the min write speed such a card must have.

The reason I ask is because on going to purchase a V90 card I noticed they each have a different stated speed rating for writes. For example

SanDisk 128GB Extreme PRO SDXC UHS-II - 300MB/s Read / 300MB/s Write
Kingston Canvas React Plus 128GB SDXC UHS-II - 300MB/s Read / 260MB/s Write
ProGrade Digital SDXC UHS-II V90 Iridium (128GB) - 300 MB/s Read / 200MB/s Write

So they all have the same read speed, but they vary quite significantly in the write speed.

Will I still be able to record on all the modes that require V90 using the ProGrade card at 200MB/s since it's still classified as V90?

 

[DMKAlex]

Will I still be able to record on all the modes that require V90 using the ProGrade card at 200MB/s since it's still classified as V90?

I believe so.

I am shooting UHD @ 60 fps, with biterate of 200 Mbps mode with Lumix Gh6 and I don't have an issue with writing speed.

 

[Sean Nelson]

Yeah, I believe the "V" specs for SD cards specify minimum write speeds (i.e., V90 = 90MB/sec), so if a camera specifies a V90 card it should work at that minimum speed and if a card truthfully claims to be a V90 card then it should be able to accept data from the camera at that speed. If the card can write faster than that minimum speed requirement then you won't see any real benefit while recording, although a faster read speed would help when uploading data to your computer.

Watch out, though, because memory card specs are like lies, damn lies and statistics. A "V90" card may claim to write at 300MB/sec, but that 300MB/sec claim may be a peak speed under certain very specialized conditions and may not be sustainable over the long run. If it's truly V90 compatible, then it SHOULD be able to sustain 90MB/sec continuously as required by a camera, but anything beyond that may just be marketing speak that doesn't have that much validity in real world applications.

Also be aware that the V90 spec is for cleanly formatted cards - a card that's been record on, had files erased from it, recorded again, etc. may end up with some fragmentation which could limit the speed to less than 90MB/sec. This is why I always reformat my cards rather than deleting files from them.

 

[CanonC100User]

Do remember that capital M and B after the number indicates MegaBytes, so for example, 90MB/s is 720Mb/s. I'd be surprised if your camera was outputting that sort of bit rate. Small b indicates bits. There are 8 bits to the byte.

 

[sludge21017]

V90 rated, that's it!

 

[erotavlas]

Do remember that capital M and B after the number indicates MegaBytes, so for example, 90MB/s is 720Mb/s. I'd be surprised if your camera was outputting that sort of bit rate. Small b indicates bits. There are 8 bits to the byte.

Yeah I forgot about the conversion. The max my camera outputs is 600Mb/s / 8 = 75MB/s which is well below the V90 spec of 90MB/s.

 

[BobKo]

I have two cameras that I use all the time to record 4K at 120fps: a Panasonic GH6 and a Panasonic G9m2. I have never owned a V90 card... I have used only V60 cards. And they work perfectly to record 4K/120. In particular, this is the card I use: https://www.amazon.com/dp/B0B94S6H7P

Edit: I looked to see what the data rate is for 4K/120 on the Panasonic GH6, and it is around 280Mbps. No trouble recording that on the V60 cards I have. I do not know what the data rate is for the Sony camera that kicked off this discussion -- but it is easy to check by looking at the properties of a video.

 

[erotavlas]

Thanks for pointing that out, Seems to be similar for my camera except for 120p. I get a warning on screen when I try 4K 120p that says to use a card higher than V60. I double checked and from the manual for this camera Sony a6700

XAVC HS 4K 280Mbps - SDXC V60 or higher
XAVC S 4K 280Mbps - SDXC V60 or higher
XAVC S HD 100Mbps - SDHC/SDXC card (U3 or higher)
XAVC S-I 4K 600Mbps - SDXC V90 or higher
XAVC S-I HD 222Mbps - SDXC V90 or higher

I checked the modes for XAVC S on the camera settings for 4K including 8bit vs 10bit and some require higher than V60, even 120p. There was confusion because the manual isn't clearly stating every single mode and the speed requirement.

So I could probably get a V60 card instead and save some money, but I'll be locked out of some of the recording modes.

 

[BobKo]

I checked the modes for XAVC S on the camera settings for 4K including 8bit vs 10bit and some require higher than V60, even 120p. There was confusion because the manual isn't clearly stating every single mode and the speed requirement.

So I could probably get a V60 card instead and save some money, but I'll be locked out of some of the recording modes.

My Panasonic cameras have a nice 4K 10-bit 4:2:2 All-I mode that records at 400Mbps. I have no problem with that mode using V60 cards. But I seldom record at rates higher than 4K/120 at 280Mbps. There are a couple modes on the cameras that I use that go that high -- for example, both cameras have a 5.7K mode that records at 275Mbps that I use all the time, and have never had a glitch with V60 cards.

Of course, if you do work at bit rates higher than that, then you gotta get the cards that will work without fail.

 

[erotavlas]

I decided to not get a V90 card in the end. The are too expensive and I realized I'm not going to use those super high bit rate modes anyway. So I ordered a V60 card with larger capacity of 256gb. It was about 3 times cheaper than an equivalent V90 card.

 

[BobKo]

I decided to not get a V90 card in the end. The are too expensive and I realized I'm not going to use those super high bit rate modes anyway. So I ordered a V60 card with larger capacity of 256gb. It was about 3 times cheaper than an equivalent V90 card.

Let us know how it works.