Questions about SD ratings

[Slickone]

After looking around at SD cards to buy, I've got a several questions, especially about Sandisk.

Am I right that the class rating is a minimum and the X rating is a maximum? So, when looking for an SD card and thinking about not wanting any bottlenecks when taking photos (not worrying about transferring from the card later), I only need to be concerned with the class, correct?

What speed should a recent Canon point and shoot max out at? I've got an SD800IS, but rarely shoot at it's max res setting. I've had to wait on the picture to save before, which I'm assuming was because of the Kingston Ultimate 120x I was using at the time. I don't know what the class rating is though. Does anyone know? That would tell me that I need a class at least above that.

Also I have a Jazz HDV-178 (720p) camcorder. I've read to use class 6 or higher for HD. Is that fast enough for perfect A/V sync?



In regards to Sandisk SD cards...

Edit: Never mind this part:
Considering the "MB/s" specs that they state for their cards are also minumums, this states a Sandisk Extreme SDHC 30MB/s in 4GB size is a class 6, but why is the exact same Sandisk Extreme SDHC 30MB/s, but in 8GB size, a class 10?

And then why is the Extreme III 4GB SDHC also a class 6 like the Extreme 4GB above, but rated at only 20MB/s?
Also curious why it doesn't state the speed on the label like just the "Extreme" does.


BTW, did "Extreme" replace the "Extreme III"? I don't see the EIII on Sandisk's website. Is there a difference?

 

[Slickone]

Scratch the Sandisk part. I figured out it was a mistake on adorama's website. The title for the Extreme 4GB said class 6, but the picture of the card itself shows it's a class 10.
But still wondering if the "Extreme" replaced the "Extreme III", and are exactly the same. I was thinking the Extreme III changed to 30MB/s at one point too.?

 

[Slickone]

I guess I'm talking to myself, but...

Maybe it wasn't a mistake afterall. I emailed Adorama about the title saying class 6, but the card label showing class 10, and they sent me a long confusing reply (see below).

Also I looked at an Extreme III 4GB advertised as 30MB/s that I got a few months ago, and it only says class 6, and also says "up to 30MB/s". It's 30MB/s, but only class 6, compared to the 8GB 30MB/s Extreme I linked above, which is class 10 (and maybe the 4GB Extreme for which the card label says class 10 even though the title says class 6). So according to the email Adorama sent me, the "Brand Refresh/Packaging transition" changed the class rating from 6 to 10, but seems to really be the exact same product. I don't know if this Brand Refresh/Packaging transition and rating change means when it went from the Extreme III (later 30MB/s version) name to just the Extreme name, in which case means the Extreme III 30MB/s version would then be the same card as the Extreme class 10. Or if they mean it happened somewhere down the line in the Extreme's product cycle (but I think the name Extreme hasn't been out long?).

Here's the email Adorama sent me:

---------------------------

Hi,

Announcement:

Panasonic has launched the 'Class 10' series of SDHC cards. Class 10 is a new speed specification developed as part of the new SD 3.0 specification. (4GB-32GB). This Class 10 cards will have its maximum speed of 22MB/s according to the release. Shipping in Europe starting June.



SD 3.0 Background:

SD 3.0 specification included few different components, key items are:

1. Higher Capacity specification to support greater then 32GB. (aka: SDXC)

2. New Higher Maximum Performance specification (aka: Ultra High Speed)

3. Change in Class measurement criteria and addition of Class 10.



SanDisk's Response:

With the above specification change, previous Class 6 products can now mostly meet Class 10 specification.

Which means, our Extreme SDHC cards, previously Class 6, will certainly meet Class 10. (And that's what Panasonic did)

SanDisk Extreme SDHC - 30MB/s Edition cards will be transitioning to Class 10 and we're coordinating the transition with the Brand Refresh/Packaging transition. (Please keep in mind this transition will be Blind roll, no SKU/UPC change)



SanDisk SDHC Product Line Up

Blue SDHC: Class 2

Ultra SDHC: Class 4 (Yes, it will stay at Class 4, All cards shipping today are Class 4)

VideoHD SDHC: Class 4 --> Will transition to Class 6 with Brand Refresh

Extreme SDHC: Class 6 --> Will transition to Class 10 (30MB/s editions) with Brand Refresh



Speed Class:

Please see attached presentation that walks you through speed class and brief info on SD 3.0 specification.

Speed Class was developed to ensure video streaming recording speeds are met.

It's ironic that today, there isn't really any video (even at highest definition video) that requires Class 10 speed.