PDA

View Full Version : digital memory question


cropper
10-31-2005, 01:47 PM
I have read through all the posts I can find and didn't really see the answer to this question. (However, I have found lots and lots of info that I never considered!!)
How do you tell the difference between brands or even within brands, not size but speed? For example, SanDisk has 2 (or more) cards that are 512...one is simply 'SD 512' and the other is an 'SD Ultra 512'. I don't see any other numbers on the packaging to be able to compare.

I an needing to buy a new memory card (SD) prior to my WDW trip because I am not taking my laptop with me on vacation since it belongs to my employer.
I was going to buy a 1GB until I saw several suggestions regarding 'if your card goes bad, everything is lost'. Now I am thinking of buying 2 smaller cards.

Please advise. I have compared brands on-line and several local superstores but don't seem to be able to compare the cards.

AZ JazzyJ
10-31-2005, 02:58 PM
You've found of the the most frustrating points of digital photography, there are no standards for describing memory card speed. Some manufacturers quote read speed, some quote write while others give theoretical transfer numbers making it difficult for consumers to compare. Lexar for example describe write speeds and you will see most of their higher end SD cards running at least 32X which is approximately 5 megabits per second (MB/s). Sandisk on the otherhad speaks in terms of transfer rates without quoting times rates. The Ultra cards are capable of achieving write speeds of 9 MB/s and reads of 10 MB/s which is approximately 60x. Write speed is the most important thing for capturing the image while read speed is important for getting the image from the camera to the computer or printer for output. Standard SanDisk SD cards have a rating of around 4 MB/s or 20x. The other thing to remember is that not all cameras are capable of taking advantage of these high transfer rates. In those cases buying faster cards may not improve your capture speed.


Jeff

Geoff_M
10-31-2005, 03:02 PM
Go look at Rob Galbraith's CF database to read about some of the issues that surround the performance of digital media.: http://www.robgalbraith.com/bins/multi_page.asp?cid=6007

I realize that this won't help you with SD format cards, but the concepts that Rob talks about should still apply. Mainly that cards often perform differently in different cameras. For example I have a couple of CF cards sold by SimpleTech that work fine in my CoolPix 950 point-n-shoot, but are slower than molasses in my D1 dSLR. As for SanDisk, the "SD 512" would be their "normal" speed card, then came the "Ultra" and then the "Ultra II" cards. Each reporting to be faster. If you look at the boxes you should see a transfer rate speed indicated, but they are a lot like EPA MPG estimates: "Your results may vary."

ducklite
10-31-2005, 03:26 PM
I use the SanDisk Ultra II cards in my D70. I do a lot of low light, no flash, photography of fast and unpredicatably moving people with constantly changing light sources and levels, and have found that they work best for my purposes.

I have tried a couple other types of Flash Cards, and nothing else has worked as well. I've got two friends who do the same type of work as I do, and we all agree, the 1MG cards work the best for us.

Anne

Razor Roman
10-31-2005, 03:59 PM
general rule of thumb, faster cards reduce the amount of time it takes between shots.

Ultra II's are great for that reason. I'd say if you can afford the size you want in an Ultra II it's worth it, just because you don't want to miss that "once in a lifetime moment" because your camera is saving that shot from before where you blinked.

cropper
10-31-2005, 04:30 PM
I very much appreciate this info!! These boards are wonderful!!

I am still undecided as to which one(s) to buy!! I have almost decided to buy a couple of smaller ones instead of 1 larger one....just in case it fails I won't lose everything. Is that a good idea? Or unnecessary? At home, I download after each event and back everything up. My worry is in WDW for a week without the computer.

I have a Minolta Dimage Z1 and only take your standard 'home shots'. I don't do anything professional or even pretend to....although I am addicted to scrapbooking with my end results.
So, how much difference will all this make? I understand the concept of missing that shot but most likely, it would be me not taking it fast enough. I know my camera does continuous shots but have no idea how. (It might be a benefit to figure out before I get to WDW!!)

I looked at the packageing at WalMart last night and didn't see any 'speed' indications on what they sell. The only place I have seen such info is on-line and you are correct, everyone speaks of different numbers.

I am soooo confused!!!!

Razor Roman
10-31-2005, 05:07 PM
I am still undecided as to which one(s) to buy!! I have almost decided to buy a couple of smaller ones instead of 1 larger one....just in case it fails I won't lose everything. Is that a good idea? Or unnecessary? At home, I download after each event and back everything up. My worry is in WDW for a week without the computer.


Definately not a bad idea... I carry in my bag a 1gb, 1 512, and 2 256s. On a prior trip to WDW, I forgot the 1gb, and my 512 got an error in one of the files. The camera would crash whenever it tried to load it. Every picture on there was fine, and the picture is fine to this day on my hard drive. Also had no problems with the card since. :confused3

But, since I forgot a card, I had to pay $12 to get a 256mb card transferred to CD, and still ended up running out of room on my last day.

Transferring the 512 to CD (Which would have been the same price) failed, becasue of the error in that file. :(

ducklite
10-31-2005, 05:55 PM
As far as the size of the chip, it depends on what you are using it for. I have four 1 mg cards for my D70, but I have very special needs. I do concert photography, and am allowed the first two or three songs, depending on the band, and that's it. So the last thing I want to do is run out of space and have to change a card in the middle of those precious seconds.

If the assignment asks for RAW, then I can fill two cards in three songs without even trying!

Anne