Leslie Cheung 
, Jan 29, 2012; 01:51 a.m.
different SDHC cards? I don't machine gun and I really never paid much attention to their speed / classes before. I need to get a few new cards, so...I figure I'd ask here. Also, I was at a local store and they had two different brands but I was confused by...
Brand X was class 4 and stated 100x
Brand Y was class 10 but stated 10x
yet, same gb size and same price.
What am I missing? Or is this just marketing BS. Does "speed class" really matter? BTW, I'm getting these new cards to experiment with short hd video making. Do speed classes (or brand) matter for me? Let me know what your thoughts, thanks!
Michael Chang , Jan 29, 2012; 02:10 a.m.
Leslie Cheung , Jan 29, 2012; 02:43 a.m.
Michael, I'll read later but I was hoping for a condensed version from someone here:) You have any related memory card experience?
Franklin Polk , Jan 29, 2012; 02:57 a.m.
It depends on the camera and what you're planning to do with it. As you mentioned, for infrequent continuous shooting, it really doesn't matter. The 'class' is readable by the camera; some cameras will not allow certain types of shooting if a certain class isn't met, which would be relevant for your HD videos. Check the manual and see what it requires for the shooting that you are planning.
Richard John Edwards 
, Jan 29, 2012; 05:52 a.m.
With Long Exposures it seems to take quite a while to process the information, would this be because of the Card?
Michael Chang , Jan 29, 2012; 06:43 a.m.
Richard, you're probably observing the camera's noise reduction time for long exposures. It does a dark-frame subtraction which basically takes another exposure of the same duration and subtracts the two frames.
Leslie, the "Class" designation adheres to SD standards. However, because manufacturers use different flash memory chips to make SD cards, some will be capable of much higher burst speeds which is not part of the SDA specification but useful for rapid still shots, for example.
So basically there is "Class" speed which is an industry standard, Maximum speed (or burst speed) which is specific to a card's design, and "Bus Speed" which is the speed of the equipment in which the card is used such as your camera.
The "X" rating of speed will not be meaningful unless the measurement condition is specified. Typically "write" speed is more important for camera use, but the "X" rating might refer to best case "read" speed under ideal conditions.
For your HD video recording, the sdcard site I linked to suggests Class-10.
Leslie Cheung , Jan 29, 2012; 10:58 a.m.
For your HD video recording, the sdcard site I linked to suggests Class-10.
Michael, do you have personal experience? this, the following info from your link:
- Class 2 : H.264 video recording, MPEG-4, MPEG-2 video recording
- Class 4: MEPG-2 (HDTV) video recording, digital still camera (DSC) consecutive photo shooting
- Class 6: Mega-pixel DSC consecutive photo shooting, professional video camera
- Class 10: Full HD video recording, HD still picture consecutive shooting
sounds like a...I don't have a clue technical writer to me, or at best...I know a little but not enough. But they all seem okay for hd video recording tech writer.
FWIW I have shot hd video before with class 4...Just wondering if there are noticeable difference *in practice* between classes. Maybe I'm too skeptical but I'll do my own testing and see. Smells like a confused writer due to SD marketing BS to me. I do have one class 10 card and a bunch of class 4 and 6's...So, I test them out myself soon enough. Just wondering if I would be wasting my time, that's all...
Leslie Cheung , Jan 29, 2012; 12:11 p.m.
Or the differences are really that murky...Anyone?
Christopher Sperry , Jan 29, 2012; 12:32 p.m.
Arthur Plumpton 
, Jan 29, 2012; 02:00 p.m.
Christopher, the Hoodman site indicates that these are especially strong (mechanically) and waterproof SD cards, but otherwise rated at class 10 (Like other consumer cards of the same speed).
Leslie, I'm not sure what the X factor means, but if class 10 is the same price as class 4, I would go for the faster write speed of class 10. Another consideration is the limiting camera write speed. Mine apparently only approximates the speed of class 6. Our local La Source store (Radio Shack) had Dane-elec 16 GB class 10 cards for sale this week at $24.99, which sure beat the last 16 GB Dane-elec card I bought from the same shop last August, at $69.99. It's worth keeping a lookout for sales.
