What 'write speed' card do I need for best 4k?

[Mark Goodsell]

Dumb question here. Here it goes:

I've got to order a bunch more cards for 4k work. I want to make sure I'm going about this right and buying what I need, not MORE than I need. For the highest quality 4k out of the X70, will any speed U3 card work? Or do I need one with a minimum of 100 mb/sec WRITE SPEED? What write speed cards should I be getting for the best 4k? I thought I read that the quality will scale down if low speed cards were used (??).

For example, some of my Sony U3 cards I have been using indicate a write speed up to 70 mb/second which I have been using for 1080p work. I have other cards, that I've bought in the past, (Sony "M" cards) i have used for some of the 4k stuff I've done which are spec'd out at up to 100 mb/sec write speed. The "M" series cards cost more, but if that's what I need, then I'll just get more. Sooo ......what do I need to be buying for best 4k? And is there any reason I should stick with the 100 mb/sec cards?

Thanks a bunch!

[Doug Jensen]

SD cards are so cheap (cheaper than tape was), so why not buy the best cards you can find instead of trying to just barely get by for today? In the long run you will ulitmately save money and sleep better at night.

[Mark Goodsell]

Doug,

Thanks for the reply. I'm glad you replied ....I'm a big fan of yours and have bought a couple of your videos in the past, and watched them several times each. They have taught me a lot! Thanks for all you do from us guys in the field.

Back to the cards, I guess what I'm asking, is, will a write speed of 70 mb/sec U3 work for full 4k resolution, or do I 'need' 100 mb/sec? I've looked at several places on Sony's website, checked the 4k upgrade documents and did a bunch of Google searches. I just wasn't able to find any documentation on what the 'minimum' write speed specs should be other than class U3. Maybe I missed some specs. OTOH, maybe that answers my question ....but I thought I'd check with the knowledge-base on this forum because there are some folks here that have done way more with 4k (on the X70) than me.

Cost does matter to a certain degree. I need to buy a bunch of 128's due to being on a project for a few weeks in an area I won't have access to any U3 cards (or any cards). In addition, I found a few new 70 mb/sec U3's left over from my last project I can perhaps use if they'll work.

Thanks..

[Noa Put]

I only use sandisc extreme pro cards that have a 95mbs read and 90mbs write speed, their cheap, reliable and deal with 150mbs bitrate codecs without a problem (highest bitrate I shoot in), they even work when shooting raw on my blackmagic pocket camera.
Once you start to deal with higher bitrate codecs, like the gh5 400mbps bitrate codec that will come out you need a faster card.
Also important, only order your cards from a reputable dealer, I just read a topic on facebook about someone ordering transcend cards from amazon having issues with them to find out later they write and read at a much lower speed then advertised meaning they are fake, not that this is the case with everything you order from online retailers but just to be aware there is a higher risk, especially when they are much cheaper then normal. I only buy cards from a large videostore that's located in my country.

[Donald McPherson]

Noa this is so true, there are a lot of fake cards out there. After reading posts for years. One question that pokes its ugly head up from time to time is. Why can I only record a few seconds?

[Pete Cofrancesco]

I can understand about saving money. I have two 4k cameras with dual cards and often have back to back jobs so if you want extra cards to pull and rotate the cost can really climb with 128 and 256gb. I've must have spent $500 on cards the past year.

My best low cost card is Transcend 70mbs it's gold color. Obviously SanDisk is the best but I've never had a problem with Transcend. I'd rather have more cards than trying to cut corners and not have enough.

[Ron Evans]

You need a minimum write speed of 30MBs they are V30 cards U3 speed rating 10. Since there are 8 bits in a byte these cards are good for 240mbs. The cards are sometimes confusing as they quote max speeds not sustained that you need for video. The cheaper cards do not always quote minimum write speeds. I use Sandisk Extreme too, as well as Lexar 1000x.

[David Knaggs]

Originally Posted by Mark Goodsell

I found a few new 70 mb/sec U3's left over from my last project I can perhaps use if they'll work.

Hi Mark.

You've made the same error that I initially did (before I bought my Z150) when I was looking at compatible cards for 4K and quickly glanced at the "100 Mb/s" as written on the Sony site for max 4K recording. Then I went to the dealer and asked him where I would put the XQD cards. From the look on his face as he showed me where the SD cards went, I realized that I hadn't really paid any attention to whether they were bits or bytes in the specs! (As Ron has pointed out in the previous post.)

Your U3 cards actually do 70 MB/s rather than 70 Mb/s, so you should be fine with what you've already got!

Also, as Doug said, SD cards are very cheap (not like the old EX1 days with the very expensive SXS cards!) I just picked up a 128 GB top-of-the-line Sony SDXC card for only A$115 (US$78).

[Mark Goodsell]

Your U3 cards actually do 70 MB/s rather than 70 Mb/s, so you should be fine with what you've already got!

Ah ha!! Ok, thanks David. You're right! I'm blushing. I guess I wasn't paying attention just like you said. Ok, that clears things up for me. So my current cards will work and I'll look over what I need to buy. I probably need 10 cards so it DOES add up pretty quick.

Thanks guys for your help. Now on to the next problem: getting my System 10 wireless to work right...

[Mark Goodsell]

BTW, I ran across this Sony SD card document which is kind of useful info about their cards and compatibility:

https://www.sony.net/Products/memory...ksd/index.html