----- Original Message -----
From: "Russell McMahon"
Sent: Monday, November 24, 2003 2:35 PM
Subject: Re: [EE]: Compact flash write speed in digital camera


> BUT I found that a 256 MB Kingston was almost twice as fast as a 512 MB
> Kingston of the same nominal spec !!!!!!!!!!!!!!

CF's are rated in 'X's, a lot like CD drives, but an X doesn't mean the same
thing between manufacturers, and read and write speeds differ as well.  the
cheap CF cards you can get at Wal-Mart are typically 4X.  Larger cards of
12X and 16X are quite common.  I think I've seen 48X cards at breathtaking
prices.

Nothing seems to have a write speed comparable to the MicroDisk, and when
you get yourself a 4 or 5 MP camera, you will be happy to have the gig of
space!

The buffer is a big deal, but so is the particular image.  A while back I
tried to clock my CoolPix 4500 at 4MP, but rarely would it take an entire
second to do the store.  Of course, as soon as I put my stopwatch away, it
took a LOT longer <g>.  The same kind of images, though, that were taking
under a second on a 12X Lexar card were taking 3-5 seconds on an older
SanDisk card that wasn't marked.

The buffer has LOTS to do with it. On my Nikon, I can take another picture
right away, I only have to wait if I want to review the picture on the
little screen.  My CoolPix will take a bunch of frames at 1.5 frames per
second, but then it needs a few seconds to catch it's breath.  At 15 fps it
can record 35 seconds, but only of low resolution images, but that is a pile
of images.

Processing also matters.  My Nikon manual indicates that turning on noise
reduction can more than double the time it takes to store an image.  I
haven't taken my stopwatch to that, though.  My daughter has an HP camera,
only 2 MP, but the processing time on that thing is horrible.  It's a few
years old, though, so I suspect what I'm seeing is increases in MIPS.

So to the original question, all of the above.  Newer cameras are faster,
have more buffer which makes them seem faster, and probably have faster CF
cards.  All the diferent formats use basically the same technology, so I
don't think there's an advantage to going to one of the other memory
formats.  In fact, being larger, it seems like the CF cards get the faster
technology sooner.

72/73 de WB8RCR    http://www.qsl.net/wb8rcr
didileydadidah     QRP-L #1446 Code Warriors #35

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