Sandisc SD

Has anyone had any long term problems with Sandisc memory cards as I have hears rumours that they don't last long before giving problems.
Shouldn't memory cards last indefinatley?

Memory cards have a finite life, but it is a very long life. Eventually individual areas may fail and the whole card will eventually fail.

Personally I have not had one give up yet. I always use branded cards such as Fuji or Sandisk.

IMHO Sandisk cards are about as good as they get, and with proper handling should last you many years.

However like most electronic items they can be susceptible to damage by electrostatic discharge, so avoid touching the contacts, make sure the camera is OFF before you insert or remove the card, and if you use a card reader with your PC, go through the "eject hardware" procedure before removing the card from the reader.

You can't legislate for random events like a cosmic ray interacting with your chip either!

I think that there is also a limit on the number of write/wipe cycles that the chips can sustain, but it is so high I think most of us are unlikely to encounter it. (I'm sure a true expert like Matt will have the numbers to hand)

I have a bunch of cards and try to ensure that I cycle through the lot, rather than using one card over and over again. I also try to remember to re-format the card each time I put it in the camera (not always easy if you are in a hurry to catch a shot!)

Tim,

Please can you develop the reasoning behind that comment?

I always reformat when I'm going to re-use a card, but it may be some time before it actually does get used. Are you suggesting it should be done at the actual point of insertion for re-use?

What exactly does a reformat do? I assume it puts any model specific information on to the card. Does it also wipe all data or just the directory?

Michael

As risk of incurring much derision from those here that do do all this, I don't.

In 8500 shots, with an average of about 20 shots between each image harvest, I've never once switched off the camera or ejected hardware before pulling the card. I don't switch off between lens changes either.

So far (famous last words ) I've never had a card problem, either, and I don't get the impression I suffer from sensor dust any more than average.

I may well have just been lucky, but I suspect the likelihood of things happening if you don't take these precautions is a lot lower than the occasional scare might suggest. I also suspect that when problems do occur, they're attributed to not taking such precautions, without much actual evidence for this being the cause.

I do, however, treat all these things extremely gently, never forcing, never bending, never applying any more pressure than required to just get lenses, card doors, cards in readers, etc, to 'click home'.

No derision, but what you are doing involves a risk and it is not "good practice". But you already know that.

In reply to "what does a format do?" it sets up the directory structure of the card afresh for the camera in use. This also helps to prevent any card issues and maximises the available space on the card.

All these things can be ignored and all sorts of things can be "got away with", but, with respect, it's sloppy working and it may have consequences.

Ah, but this is the thing. It may involve a risk, but it may prevent other risks.

I probably change lenses about as often as every 20 shots too. So in a year, I've saved something close to 1000 off switch operations by not switching off for a card removal or a lens change. (I never turn SR off on the tripod either. )

Who can say whether if one of my cards dies, it's actually related to my lack of good practice, or something else. And maybe the 1000-odd switch operations would result in an earlier failure, and a more expensive repair than the replacement of the odd card.

I don't think the actual probability of any particular failure mode is high enough for a definitive answer to this one.

The reason given for turning the camera off before a lens change is usually that the sensor is charged when the camera is on, therefore more likely to attract dust, and with the lens off there's more chance for dust to get in.

I don't understand the logic there, as the sensor is behind the shutter, which would be an effective barrier to any dust. If the sensor were exposed all the time, I would understand.

Anybody got any thoughts?

Dan

The static charge will attract dust which will land on the filter that covers the sensor. The charge is not stopped by the filter. Agreed that it can't land on the CCD itself, but the effect will be the same.

But the shutter will be infront of the sensor and filter. Any dust that would get attracted would be behind the shutter, and therefore would not be increased by having the lens removed.

Dan

You mention a filter in front of the sensor. What is this made from? If it is glass why is sensor cleaning viewed with trepidation by some people? I have thought about what to do if mine needs cleaning and the different methods mentioned by people has concerned me to the degree that I don't really fancy the job.

Rob

Yes, I thought that, but when the shutter is released the air movement chucks any debris in the mirror chamber all over the place, including on the sensor. Also, there might well be some slight amount of wear and tear debris from the shutter assembly itself.

"You mention a filter in front of the sensor. What is this made from? If it is glass why is sensor cleaning viewed with trepidation by some people"

I presume it is glass, but it is coated with a special dust-repellant surface in the K10D. using cleaning products that touch the surface could abrade the finish. Using inappropriate liquids could damage the coating.[/quote[/quote]

This dust problem is something I realise is much more serious in Digital than in Film cameras. A few puffs around inside when you changed film was usually enough. But then again I couldn't take 300+ pictures without it costing me an arm and a leg! Which is why I am trying to find out about memory cards 'cos that's one of the many things I know little or nothing about.

Rob

I think the simple answer is to buy well known branded cards from a reliable source so you know they aren't fakes.

The price is very low anyway, so there's little to lose and much to gain.

I reformat upon insertion, because otherwise I'd forget!

I reformat frequently because I read somewhere on the 'net that the computers and cameras handle files slightly differently and that there is a small risk that when a file is deleted from the card by a computer, it may not be correctly deleted and hence allow some data corruption to occur. It's just another of those things that some people claim to be "best practice"

Edit:-

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