memory cards

this is probably a pretty pointless question. but out of curiousity,

does anybody know why my scandisk ultra II 1.0 gig memory card holds 7

less than my PQI hi-speed 40 1.0 gig memory card? (all settings the

same, just switching out the cards) I would guess it is just the

result of different manufacturing but thought maybe there was some

really cool reason.

Aliens. Sandisk wouldn't hand over their first borns for the breeding program and so they get inferior technology.

 

I, for one, welcome our new PQI overlords.

7 .cr2? or high res jpeg? or?

 

Hard drive manufacturers use creative math, multiplying bits by 1000, instead of 1024, to get define their drive's gigabyte capacity. Perhaps Sandisk is a little *more* creative than the other guys?

 

FWIW, I get 215 full size .cr2 files on a 2 gig sandisk.

i think i like robs answer.

 

7 more fine jpegs in a 20d .. that is less difference in raw, like maybe a couple. but I thought to ask.

i think for raw it is 109 and 105 but I am not going to check right now.

 

overlords huh. pqi is better? well if you say so, i hadn't paid enough attention to the different manufacturers. I have been told PQI is better but I never heard of them and Scandisc cards are much prettier, you know with all that glossy writing on them and stuff... plus Ultra II? .. you can't beat a name like that, hi-speed 40 is a cheesy name.

 

alright. well thanks for the responses. :)

<p>Yes, hard disk manufacturers consistently overstate the capacity of their drives by conveniently redefining standard measurements. But that doesn't fly with flash cards, since the chips in them all do addressing in binary and therefore are actually of the capacity they say they are; a "1.0 GB" flash card using the hard drive industry's definition of a gigabyte (approximately 954 MB) would still require the same amount of flash memory (1 true gigabyte) as to make a true 1.0 GB card, so they can't shave cost by lying about the size of their cards.</p>

 

<p>I have three of the same 1 GB card, from the same reputable brand, with identical firmware on each one. If I format all three the same way, two of them have a slightly higher capacity than the third. I can change the capacity of each by formatting differently (ion camera vs. in PC, FAT vs. FAT32, and different cluster sizes for FAT32), but as long as I pick the same formatting method and settings, one of the three is consistently slightly smaller.</p>

 

<p>One possibility, and this is just a guess, is that there's a manufacturing defect on one of the cards, which resulted in a few flash cells being defective. The cards are supposed to map these out as they're discovered, to prevent you from writing files onto known defective cells. Perhaps that's what's happening.</p>

 

<p>Keep in mind, too, that every image file, whether RAW or JPEG, is a slightly different size than the others. The RAW files I brought back from a recent trip average out to 7926 kB, but the smallest is about 15% smaller than that and the largest is almost 25% larger. So even if I were to take the two cards I have which format to identical capacities and then shot with each one until it was full, I'd probably get different numbers of photos on each one.</p>

With my 2 gig sandisk card in a reader, checking it's properties in Windows explorer, it's just 2 (something) bits, not truly 2 gig. In other words, they use the same trick as hd makers.