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View Full Version : High speed 80X CF 512mb/1gb cards worth extra price?



PLMurphy
01-26-2005, 07:38 AM
Apparently the compactflash memory card leaders SanDisk and Lexar keep outdoing each other in speed and capacity, but no where is there a guide as to what speed card should be bought. Nor is their info on buying Type I or Type II cards. Maybe no one knows?

I use a Canon Powershot G6 for family photos. One reason is the burst mode of rapid pictures of people. Currently I have installed a SanDisk 512MB Ultra CF card. I am buying a second card of 512mb/1gb for a trip. Thus my interest in a few specs about purchasing.

Rhys
01-26-2005, 10:01 AM
Apparently the compactflash memory card leaders SanDisk and Lexar keep outdoing each other in speed and capacity, but no where is there a guide as to what speed card should be bought. Nor is their info on buying Type I or Type II cards. Maybe no one knows?

I use a Canon Powershot G6 for family photos. One reason is the burst mode of rapid pictures of people. Currently I have installed a SanDisk 512MB Ultra CF card. I am buying a second card of 512mb/1gb for a trip. Thus my interest in a few specs about purchasing.

High speed cards are only needed if you're shooting with very large file sizes with photos taken in rapid-succession. As an example: an unrated CF card will write at 2mb/sec therefore a 40x card will write at 80mb/sec. If your file size is 35mb (a large raw file) then you'll benefit from a 40x card. If like the rest of us, you use 1 - 2mb files then you won't see any benefit. A fairly good rule is that if you can write two photos per second, you're at the limit of the number of photos you can realistically take in a second.

PLMurphy
01-26-2005, 10:42 AM
For saving RAW images and using no more than a 11X14 size, do I need a 512/1gb card? I offload images to a computer for editing in Adobe Premier Elements/Photoshop. Any prints are done by SnapFish.

From your previous answer it sounds like the regular(4mb tnsf speed), less expensive, CF card from either Lexar or SanDisk is the one to buy. The Ultra being "overkill"? However I do sometimes use the burst mode for rapid pictures.

Rhys
01-27-2005, 04:40 PM
For saving RAW images and using no more than a 11X14 size, do I need a 512/1gb card? I offload images to a computer for editing in Adobe Premier Elements/Photoshop. Any prints are done by SnapFish.

From your previous answer it sounds like the regular(4mb tnsf speed), less expensive, CF card from either Lexar or SanDisk is the one to buy. The Ultra being "overkill"? However I do sometimes use the burst mode for rapid pictures.

Your camera might have a built-in buffer to cope with this situation. Many do. That might solve the problem and enable you to use slower cards. I have no intention of upgrading mine until I must. I'm still very happy with 3 megapixels.

dwig
01-30-2005, 07:00 AM
While some of the speed differences are univeral, much of the extremely high speed capability requires the device, camera or reader, to have special logic to use it. Without that special logic, the card performs as a normal speed card.

Very few Point&Shoot cameras have the additional firmware logic to take advantage of the highest speed cards. Getting a "faster" card will not change the behavior of these cameras. The newer generation of dSLRs often do.

Most plain vanilla USB 1.x card readers also fail to have the necessary special support. Its generally found only in a few brands (those that offer the cards) and then only in the newer USB 2.0 or FireWire readers.

If your camera doesn't support the high speed function of the card it may still be of some advantage to use one if you get a reader that does. The camera won't shoot faster but copying a full large card to your harddrive would take less time.

Also, the camera's processor has to "think" about the image to create the data file. This processor overhead is often the bottleneck and a faster card is of no value, Shooting in the RAW mode, on cameras where it is available, will bypass much of this overhead and gives value to the camera having support for a card's excellerated write functions.

D70FAN
01-30-2005, 07:57 AM
Also, the camera's processor has to "think" about the image to create the data file. This processor overhead is often the bottleneck and a faster card is of no value, Shooting in the RAW mode, on cameras where it is available, will bypass much of this overhead and gives value to the camera having support for a card's excellerated write functions.

So the file size has no bearing on how fast the file transfers from buffer to flash card? In that case my D70 must not be working very well as it takes twice as long for a 6MB RAW file to transfer (in-camera) as for the 3MB fine JPEG. In fact as the JPEG file is made smaller by compression it's even faster.

So I'm thinking that, at least on my D70, the I/O bus speed, and flash card (on-board) memory controller, has more to do with this than the internal processing time.

Externally, any USB2.0HS reader (and a USB2.0HS equiped computer) will be an asset to download speed, even with a standard speed card. I have tested this myself just recently. USB 2.0HS with a standard 1X Kingston 512 card was 5X faster downloading than USB 1.1 (or USB 2.0 Full Speed).

The PQI 40X card was twice as fast at downloading (497MB of NEF files) as the 1X Kingston card (on USB2.0HS). But this was only a difference of 1 minute vs. 2 minutes for the slower card.

Here is an interesting article on card speed as it applies to various cameras.

http://www.robgalbraith.com/bins/multi_page.asp?cid=6007

dwig
01-31-2005, 07:56 AM
So the file size has no bearing on how fast the file transfers from buffer to flash card? ...

The size of an individual file has some impact on the download time comparisions. There is some overhead in any file system that comes from finding a particular file (reading a directory, ...) prior to actually reading its data and this overhead is the same regardless of whether its a 200k file or 20meg. Downloading a 512 meg card that has 500 1meg files (500 directory reads at the source and 500 directory writes at the target) will take longer than downloading the same card when it has 25 20meg (on 5% as many directory operations on each end) files even though you are moving 500meg of data in either case. If the pipline (USB1.x, USB2.0, FireWire, internal bus, ...) is the bottle neck, the difference may be less because the source device may be able to use the time waiting on the bus to do some file access. Also, buffers and caches can make more efficient use of processor power when they are available; to such an extent that some data transfers show similar times with any card.

Myhre
02-11-2005, 02:49 PM
Here is an interesting article on card speed as it applies to various cameras.

http://www.robgalbraith.com/bins/multi_page.asp?cid=6007

Indeed, it is very nice to have a reference table that covers the Write time for so many Camera's. I havn't checked to see if you guys have stickies around here but I think that this link is a perfect candidate for one.