Heads Up on SD Cards


bforbes

Link Posted 07/02/2010 - 18:29
Are all USB 2.0 card readers not capable of the same transfer rate?

When you are talking of the 30MB/s cards what class would they be called?

I'm learning here
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

bretti_kivi

Link Posted 07/02/2010 - 18:43
Quote:
Are all USB 2.0 card readers not capable of the same transfer rate?

hell no. There is one model IIRC that's capable of sustained 24MB/s and I have one. Yes, it does. c't tested them a couple of years ago and most did silly low numbers.

The Micromate I have reads at around 2.5MB / sec, it's painfully slow.

30MB is off the class scale, so 6.

OoI, my "USB2.0 Hub" is fine until I cane it with data. Then.... no. I plug the external disks directly into the laptop and things move along nicely.

Bret
my pics: link
my kit: K3, K5, K-01, DA 18-55, D-FA50 macro, Siggy 30/1.4, 100-300/f4, 70-200/2.8, Samsung 12-24/f4, Tamron 17-50, and lots of other bits.
Last Edited by bretti_kivi on 07/02/2010 - 18:44

Anvh

Link Posted 07/02/2010 - 18:48
Barrie don't worry you will get it

There are several things here that you need to consider.
- The speed of your computer/card reader
- Maximum speed of USB 2.0
- And the speed the card can do
The slowest of these is your maximum transfer rate, most cards can't simply go as fast even if your computer and USB allows it, since the memeory chip of the card can not handle more then MB/s for example.

Yes the Class thing is something you just need to throw out of your mind for the simple reason that the current cards are must faster.

Basicly there are 3 official class 2, 4 and 6, they simply state what the minimum write speeds is.
So a class 2 can at least do 2MB/s
class 4 = 4MB/s
class 6 = 6MB/s

Some manufactures claim they have a class 10 card but as of now there is nothing official from SD Card Association.

So a 30Mb/s you could say that's a class 30 but since the highest is class 6 it's a class 6 card, therefore these classes say nothing any more.

Some also have a rating with a x and that's based the speed with magnitude of 150 kB/s, also cd-roms use that.
So for example a 13x = 2MB/s (13 x 150 kB/s = 1950 kB/s = roughly 2MB/s)

ps. you talked about card readers and yes there are differences in them as well just the same there is difference on how fast you DVD player is for example.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Last Edited by Anvh on 07/02/2010 - 18:52

iceblinker

Link Posted 07/02/2010 - 18:50
Some USB 2.0 card readers are faster than others. They don't all have equally efficient technology.

30 MB/s could be called Class 30 if a Class 30 was officially set. But it's not, so Sandisk just call it Class 6 because it's at least as fast as 6 MB/s.
~Pete

alfiemooon

Link Posted 07/02/2010 - 19:30
Ok Anvh...sorta similar to the "Custon Car" boys..no point in putting a V8 Rover engine in a Moggy Thou and keeping the original brakes.

Two last questions to all,

1)...apart from reading the packaging before purchasing,how do you know the speed of your SD coz I can`t find any marks on the darn thing?

2)...Are there any major differences between SanDisk and SD Disk R us?


Nic
K10D,K20D
Pentax 18-55,Tamron AF 70-300,Sigma 150-500
Kenko 2X Teleplus MC7
AF 360 FGZ

bretti_kivi

Link Posted 07/02/2010 - 19:53
apart from the environment stuff? (works at -20) sort of. Kingston, Sandisk, Transcend : I would trust these guys with my data.

I don't trust cheap junk. It might be good, it might be bad; I don't want to find out.

BTW: 4GB Extreme IIIs just over a tenner at amazon.co.uk. Why chance it?

Bret
my pics: link
my kit: K3, K5, K-01, DA 18-55, D-FA50 macro, Siggy 30/1.4, 100-300/f4, 70-200/2.8, Samsung 12-24/f4, Tamron 17-50, and lots of other bits.

robbie_d

Link Posted 07/02/2010 - 20:09
I use SanDisk Extreme III 4Gb.

Got a couple more recently off Amazon for about 13-14 a piece.

I heard once that they're nearly as fast as the fastest and nearly as cheap as the cheapest, which I reckon makes them a good buy.
If you can't say something nice about Pentax, you won't say anything at all.

Apparently.

robbie_d

Link Posted 07/02/2010 - 20:10
bretti_kivi wrote:
apart from the environment stuff? (works at -20) sort of. Kingston, Sandisk, Transcend : I would trust these guys with my data.

I don't trust cheap junk. It might be good, it might be bad; I don't want to find out.

BTW: 4GB Extreme IIIs just over a tenner at amazon.co.uk. Why chance it?
Bret

Absolute bargain if you ask me. Especially as two weeks ago they were selling for 2 more. At this price I may pick up a couple more.
If you can't say something nice about Pentax, you won't say anything at all.

Apparently.

iceblinker

Link Posted 07/02/2010 - 20:38
alfiemooon wrote:

1)...apart from reading the packaging before purchasing,how do you know the speed of your SD coz I can`t find any marks on the darn thing?

2)...Are there any major differences between SanDisk and SD Disk R us?

1) You often can't tell from the label apart from the Class number, which doesn't mean much. Look up the manufacturer's website for more info.

2) There are plenty of other good cards, but Sandisk happens to be good vaue for the high-speed ones from play.com. Watch for fakes. Risky to buy Sandisk from eBay or Amazon merchants.
~Pete

robbie_d

Link Posted 07/02/2010 - 21:05
iceblinker wrote:
alfiemooon wrote:

1)...apart from reading the packaging before purchasing,how do you know the speed of your SD coz I can`t find any marks on the darn thing?

2)...Are there any major differences between SanDisk and SD Disk R us?

1) You often can't tell from the label apart from the Class number, which doesn't mean much. Look up the manufacturer's website for more info.

2) There are plenty of other good cards, but Sandisk happens to be good vaue for the high-speed ones from play.com. Watch for fakes. Risky to buy Sandisk from eBay or Amazon merchants.

No point using Amazon merchants as Amazon themselves (well their subsidiary IndigoStarfish) are cheaper than any merchants for most Sandisk cards.
If you can't say something nice about Pentax, you won't say anything at all.

Apparently.

Anvh

Link Posted 07/02/2010 - 21:07
alfiemooon wrote:
1)...apart from reading the packaging before purchasing,how do you know the speed of your SD coz I can`t find any marks on the darn thing?

2)...Are there any major differences between SanDisk and SD Disk R us?

1) Most of the time there is a class number on the card but like said that says little about it. All you can do is look at the packaging or on the website.

2) beside that what has been said I think there is also a difference in build quality. There is little that can go wrong but how they are baked and how much material they use all adds up in a better product.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

dml82

Link Posted 09/02/2010 - 10:38
i recently purchased an ADATA 16GB SDHC class 6 card. On its first day of use it said "card error" after 12gb of shooting.

Thankfully the card was fine once in the computer, but it wasn't fun seeing card error near the end of an important day of shooting.

So I'm not recommending ADATA as a brand.
www.flickr.com/photos/dml82

alfiemooon

Link Posted 17/02/2010 - 23:02
The 4GB HCSD cards in Associated Dairies are class 2...I asked the bloke at the photo counter...he`s learnt something as well now...ha ha ha.

Nic
K10D,K20D
Pentax 18-55,Tamron AF 70-300,Sigma 150-500
Kenko 2X Teleplus MC7
AF 360 FGZ
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