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Old Jan 8, 2004, 5:02 AM   #11
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csd - ok point taken. It's often difficult to strike a balance between technical accuracy which we might know from our specialisations - to getting something across that may lack technical precision, but more easily understood by photographers. There is a misconception that compactflash memory is no more than 'static ram' in a square package, so that was the point I tried to get across.

Anyway, this is a curious post because non technical photographers are told that compact flash is electronic film. And if image quality for any reason can be shown to be different (which I'm sceptical about), then it's an important matter for all digital photographers.

.....The other card seemed to right files faster and I could shoot faster sequences. It actually appeared to be a better performing card.....

Yes I think we can all agree that card speed and possibly speed/compatibility/data error issues would fit this comment exactly but there's no rule that says the more you pay, the faster the card will get and perform faster in a particular camera.

......But when I went to put them on the screen, the images just didn't look as good.....

Hst, if you see the same problem again and can post links here to two image files, then there are plenty of helpful members on this Forum who will comment. Regards VOX
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Old Jan 14, 2004, 12:09 AM   #12
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Pictures aren't any better or any worse on different brands and types of media for the same reason that mp3s sound the same regardless of what brand of hard drive they're stored on. Digital data is either stored accurately or isn't. If the card does something wrong, the result is a totally ruined image, or one with garbled or miscolored sections. Any errors in storing the file will come across as obvious defects in the image, not subtle variations in quality.
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Old Jan 15, 2004, 2:28 PM   #13
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I have seen image problems reported before with some brands of SD in some cameras.

Whether or not this has to do with bit error rates is speculation. It could even be a slight difference in the power draw from different cards -- if the voltage regulating circuitry in the camera did not compensate well enough for the card being used, and it impacted levels to the CCD or supporting chip set.
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Old Jan 15, 2004, 7:14 PM   #14
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That's precisely what I was getting at earlier! The problem may be impacting outside the cards physical environment, at the time of saving.

I know my camera has enough buffer memory to allow me to take fresh shots whilst the card is still being written to. The problem with digital thinking and error rate analysis is you can miss the simple analogue power interference, power loading impedance or emc issues, but then my background includes RF. VOX
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Old Jan 15, 2004, 7:29 PM   #15
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Quote:
The flash controller and buffering do not have embedded software. These are not considered CPU's by any means.
Processing is external to the card
i think you better rethink that statement.

as an example WA (write acceleration) programming in my Lexar Pro needed to be revised due to an error in its functionality with certain Nikon cameras. Lexar picked up the cards(2x1GB 36x pro cards) that i had reflashed the firmware in the cards and had them back to me in 2 days. same S/N's. so the cards can be a bit more sophisticated then one is led to believe today.

W/A is in 2 parts. part 1 in camera part 2 in the card and is an active function in the card with the appropriate camera/software interfacing with it.

no it is not a high level cpu function but still their controllers (which they design) are capable of higher then most cards functions and do have embedded and flashable firmware.
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Old Jan 16, 2004, 10:19 AM   #16
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Quote:
Originally Posted by sjms

i think you better rethink that statement.

as an example WA (write acceleration) programming in my Lexar Pro needed to be revised due to an error in its functionality with certain Nikon cameras. Lexar picked up the cards(2x1GB 36x pro cards) that i had reflashed the firmware in the cards and had them back to me in 2 days. same S/N's. so the cards can be a bit more sophisticated then one is led to believe today.
.
Okay - I'm rethinking as you requested... :lol:
Okay - here goes -
Not familiar with Lexar's manufacturing or parts, but more than likely they didn't reburn software (the parts I am familar with are hard-logic, not embedded) - they just swapped the controller or ECC chip with a newer version.
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Old Jan 16, 2004, 10:48 AM   #17
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i dont think so. your trying to say the pulled open the CF packaging and replaced the chip. they are "throwaways" in a hardware sense. there are no hard repairs on these. it is too cost prohibitive. it would have cost less to just give me new ones. by the way their pro cards are flashable. just call them.

they had well over 1000 of these erratum cards to do. thats the advantage of flashable tech you can sometimes "fix it in the mix". making it less costly. ask intel about the pentium 4. its capable of it too.
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Old Jan 16, 2004, 12:28 PM   #18
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As I said - I'm not familiar with Lexar's parts but don't assume it costs them less to open up your card, hook up a prom burner, and re-burn a chip than to replace it. And, if they could be upgraded with a simple reader - you would have assumed they would have just sent you the firmware to do this yourself (similar to upgrading your digicam). It is often cheaper to remanufacturer than to reburn.

You (somewhat rude-ly) told me to "rethink" which is what I did for you. I've been involved in the engineering and manufacturing of many parts similar to these so was trying to add some value based upon experience. Vox and I already had this discussion and I believe it is outside the scope of this post.

The real point to this post was whether or not bit error rates could be great enough and occur at such a steady frequency such that it isn't corrected by the ECC algorithm and occurs at such a rate not to corrupt, but to add noise to the image, OR, whether some other type of RF interference can cause a corrupted pattern of bit flips such that it will appear as image noise. If you want to further discuss engineering and manufacturing methods - lets to that off line. For now - lets get back to the original question/discussion. If you have nothing else to add towards that goal - then please feel free to flame me elsewhere.
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Old Jan 16, 2004, 12:39 PM   #19
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Quote:
Originally Posted by csd
The real point to this post was whether or not bit error rates could be great enough and occur at such a steady frequency such that it isn't corrected by the ECC algorithm and occurs at such a rate not to corrupt, but to add noise to the image, OR, whether some other type of RF interference can cause a corrupted pattern of bit flips such that it will appear as image noise. .
Hey - this sounds like a good topic for my master's thesis! We could simulate some bit errors - build a ECC algorithm (such as that employed by CF) - and feel through some images. If we get the right pattern of errors - who knows!
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Old Jan 16, 2004, 1:10 PM   #20
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they simply plug it in a cf device and rewite the code. no prom burning. just a simple flash. they hold the code though they're not giving it out. its licenced and and marketed to camera mfgrs so we ain't gettin it. things can be so easily reproduced these days as you know

i apologize if i seemed rude in did not mean to "flame" you . it is just so many assumptions are taken here (on these forums) sometimes as fact and tend to be a bit more conjecture. improvements in products are made almost hourly in the chip world. again i apologize.

i myself tend to try to reference my answers when possible. it is part of my job to do so.
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