All your eggs in one basket...

[FlyingPete]

It is often said when people are seeking advice of flash card purchases that they should opt for a greater number of smaller cards over fewer larger cards, the reason being cited that if you say get a corruption on a 8GBcard, you loose more than if you had a corruption on a 1GB card, i.e. all your egges in one basket.

Is this actually true? I have been thinking (uh oh) but I have no conclusions yet...

This is all theroetical I am attenping to get an interesting discussion going here :D

1. First lets say a card has the same chance of failure regardless of capcity for this excercise lets say 1 in 1000 hours of use. I cycle my cards so they all get used.
1. a: I own 8 1GB cards therefore there is a 8 in 1000 hour chance of a failure, however it will only affect 1/8th of my images. As statistics go after 10000 hours I would have had 80 failures and lost 80GB of images.
1. b: I own 2 4GB cards therefore there is a 2 in 1000 hour chance of failure, hoever it will affect half my photos. As statistics go after 10000 hours I would have had 20 failures and lost 80GB of images.

1.a and 1.b over time show no real difference.

2. Second lets say a cards chance of failure is based on capacity and will there is a 1 in 1000 hour chance per GB. Again I cycle my cards so they all get used.
2. a: I own 8 1GB cards therefore there is a 8 in 1000 hour chance of a failure, however it will only affect 1/8th of my images. As statistics go after 10000 hours I would have had 80 failures and lost 80GB of images.
2. b: I own 2 4GB cards therefore there is a 8 in 1000 hour chance of failure, hoever it will affect half my photos. As statistics go after 10000 hours I would have had 80 failures and lost 320GB of images.

2.a and 1.b over time show a greater risk in larger cards, i think this is possibly the more true scenario as the greater the capacity the more components the higher chance of failure.

What do you think? I know the failure rates are way too high for real life, these are just easy numbers, they also don't take into acocunt failures that don't cause the complete loss of a card

[Salleke]

My opinion is that if we buy only the best cards we shut not have much problems.
I have 4 Sandisk CF cards and untill now I have had no problems at all for two years.

Good luck for all of us CF cards users.

[sirsloop]

has anyone actually ever had a CF card fail on them?

[chris.bailey]

has anyone actually ever had a CF card fail on them?

Yep! though I did manage to retrieve about 70% of the images from it with a rescue program. Card showed as empty rather than full but would not allow images to be written to it. I ended up doing a paid job free gratis and reckon on having got off lightly!

For me the biggest problem is that if a whole shoot is on one card (8 gig say) then you loose the whole shoot. If however you shoot 4 2 giggers you would loose 25%, which would still be a problem if that 2 gig card contained all the church shots at a wedding say but slightly less of a problem than loosing the whole day.

I tend to swap cards well before they are full and make sure I have some images of each part of a shoot on seperate cards especially at a something like a wedding which would be hard to re-shoot. Swapping cards takes a few seconds so why take any risks that are easily avoided.

Remember that SODS law say that if something can go wrong it will do so at the most awkward moment.

[Jim G]

I don't think it's so much the total gigabytes you lose as the fact that you lose ALL the shots from one shoot - if you spread 'em out the shoot may still be salvageable. If you shoot weddings how are you going to explain to the bride+groom that they didn't get a single shot from this once-only event? Explaining that you missed 1/8 of the wedding (say, some of the reception) is a much easier task....

[wei328]

That's why I wouldn't buy a high capacity card like 8GB.
I rather have 4x2GBs or 2x4GBs cards instead.

[rklepper]

I guess I would say if I have four 1GB cards I am 4 times more likely to lose the card than if I have one 4 GB card. I think that chances of losing the card are much greater than the possibility of the card becoming corrupt.

[deadpass]

Is this all assuming that you guys shoot in RAW? I know rarely do I shoot more than 450 pics in a shoot (using 2gb cards) so I wouldn't be switching cards, therefore, if the card failed I'd loose the whole shoot regardless, so it's a bit of a moot point for me.

[Lester Wareham]

It is often said when people are seeking advice of flash card purchases that they should opt for a greater number of smaller cards over fewer larger cards, the reason being cited that if you say get a corruption on a 8GBcard, you loose more than if you had a corruption on a 1GB card, i.e. all your egges in one basket.

Is this actually true? I have been thinking (uh oh) but I have no conclusions yet...

This is all theroetical I am attenping to get an interesting discussion going here :D

1. First lets say a card has the same chance of failure regardless of capcity for this excercise lets say 1 in 1000 hours of use. I cycle my cards so they all get used.
1. a: I own 8 1GB cards therefore there is a 8 in 1000 hour chance of a failure, however it will only affect 1/8th of my images. As statistics go after 10000 hours I would have had 80 failures and lost 80GB of images.
1. b: I own 2 4GB cards therefore there is a 2 in 1000 hour chance of failure, hoever it will affect half my photos. As statistics go after 10000 hours I would have had 20 failures and lost 80GB of images.

1.a and 1.b over time show no real difference.

2. Second lets say a cards chance of failure is based on capacity and will there is a 1 in 1000 hour chance per GB. Again I cycle my cards so they all get used.
2. a: I own 8 1GB cards therefore there is a 8 in 1000 hour chance of a failure, however it will only affect 1/8th of my images. As statistics go after 10000 hours I would have had 80 failures and lost 80GB of images.
2. b: I own 2 4GB cards therefore there is a 8 in 1000 hour chance of failure, hoever it will affect half my photos. As statistics go after 10000 hours I would have had 80 failures and lost 320GB of images.

2.a and 1.b over time show a greater risk in larger cards, i think this is possibly the more true scenario as the greater the capacity the more components the higher chance of failure.

What do you think? I know the failure rates are way too high for real life, these are just easy numbers, they also don't take into acocunt failures that don't cause the complete loss of a card

Its an interesting analysis, but compact flash is quite rugged and very reliable. They do ware out aparantly but it takes so many cycles it is said to not be an issue.

I suspect that many supposed CF problems are due to people using the camera with the battery on in a low state. There seems to be a risk if the the display is showing 1/4 full, I always change batteies when I get to that point since I had a camera lockup event.

[SkipD]

One must also consider the probability that you will be out in the field, take your camera out of the case, and suddenly realize that your memory card is back at home in the card reader.

Someone who's been thinking and finds himself/herself in this situation will just pull another card out of the camera case (and still have a couple more spares waiting).

[peterdoomen]

As I said in another thread, I think the main risk is making a mistake yourself and losing the card, or mishandling it otherwise so that you lose pics. With several cards, you spread that risk.

For my 20D, 2 GB cards seem to be about ideal. 1 GB is too small, and 4 GB is only needed in special circumstances like marriage.

P.

[JaertX]

A few pro's I know replace their cards every year. Out with the old, in with the new.

I'm planning on trying to stretch mine out for two years and then replace them. Just another cost of doing business.

[samsen]

you can't go wrong listening to old idioms.

[FlyingPete]

Some good points here, I only took into account a 100% failure which is indeed a rare event.

Leaving a card at home etc are all good points for having multiple cards, I actually had my 2GB stolen recently luckily it had no images on it, or it would have been 180 odd CR2s gone :shock:

[dontblink]

Having the card actually fail, is not really what I am worried about. Losing the card or having it stolen seems more likely to me. However, when I shoot RAW I like to use 4GB cards, and have really standardized on that size. It is very convient to use 4 GB then when they are full, burn it to a DVD. 512 MB cards match up well with CDs.

[FlashZebra]

That's why I wouldn't buy a high capacity card like 8GB.
I rather have 4x2GBs or 2x4GBs cards instead.
When 2GB cards were uncommon, the same argument was made that you would never want a 2 GB card, but several 512MB cards. So, why are 2 GB cards so reliable now.

When 512 MB cards were uncommon, the same argument was made that you would never want a 512 MB card, but several 128 MB cards.

Long term attention to all this intrigue, indicates that all this concern just does not hold up.

Use larger capacity cards. They require much fewer insertions and removals from your camera and card readers. They require fewer downloads and reformatting. All this should help improve the basic reliabilty of the cards.

Enjoy! Lon

[gkuenning]

Peter, your fundamental analysis of the two possible cases seems correct (and insightful!) to me.

The data you're missing is that your first assumption (failure rate is per-card, rather than per-GB) is the correct one. While it's literally true that the bigger card has more components, the component count isn't really relevant to the failure rate of a modern chip.

Turning to some of the responses, it's true that statistics tell us that the failure rate is low, but that doesn't help if you get the short end of the stick. For weddings and similar critical situations, I'm pretty well swayed by the "spread your risk" argument. For regular folk like me, I prefer using the biggest card I can afford, because I tend to get confused about which ones are empty and which are full. It's so much simpler to go on a trip and know I'll have room for several days' worth of shooting.

[ScottE]

Several observations.

I know people who have lost photos because they put a CF card in a pocket or set it down after changing to a new card and then lost the card. If they had been using a bigger card they would not have had to change cards.

I have had a couple of card failures and both occured shortly after I put a replacement card in my camera after filling the first one. If this is a typical time for failure, you are less likely to have a card failure if you don't change cards as often.

In both card failures I was able to retrieve most of the photos from the card except those immediately before the failure. If you can retrieve all except the last few shots, you lose the same number whether you are using a large or a small card.

There seems to be some perverse Law of the Universe that if you lose one shot, it is the one you really wanted to get. Size of card is irrelevant.

I have shot a lot of photos with Sandisk Extreme (both original and III) and never had one fail despite being used in some rather cold tempertures in winter in Canada and hot tempertures at the equator in Africa. Obviously failures can and will occur, but with high quality cards they are very rare. If you are worried about card failure you should also be worried about camera and lens failure too. Carry two cameras and take duplicate shots of everything, one with each camera.

[tommykjensen]

Obviously failures can and will occur, but with high quality cards they are very rare. If you are worried about card failure you should also be worried about camera and lens failure too. Carry two cameras and take duplicate shots of everything, one with each camera.

Good point. How many threads do we see here regarding camera or lens failures vs card failures. Based on that the risk on camera or lens failure is much much higher than card failure (I have not counted anything - its just an observation over time).

I have switched all my small cards to 4 GB Sandisk Extreme III cards. I have 4 in total and plan on getting a couple more. I don't know if I will ever get a 8 GB or bigger card. Time will tell.

[gkuenning]

I have had a couple of card failures and both occured shortly after I put a replacement card in my camera after filling the first one. If this is a typical time for failure, you are less likely to have a card failure if you don't change cards as often.

That's a pretty interesting observation, ScottE. My understanding was that the primary failure mode was from wearing the chip out, but maybe that's incorrect. I wonder if anybody else has data on when cards fail?

I have shot a lot of photos with Sandisk Extreme (both original and III) and never had one fail despite being used in some rather cold tempertures in winter in Canada and hot tempertures at the equator in Africa.

As a general rule, electronics like being cold and don't like being hot. They're also not always happy with moisture, so your Africa experience is encouraging.

Carry two cameras and take duplicate shots of everything, one with each camera.

Well, for card failures you could just get a 1Ds II and save to two cards. If you could afford it--at the 30D level, two cameras are vastly cheaper than one high-end job.

But you're right, flash cards are much more reliable than the rest of the system. I just Googled them, and the typical MTBF is one million to four million hours. Even if we take that as elapsed clock time (instead of time powered on), it works out to 114 years at the low end.

[Lin-z]

I currently have a 6gig micro drive, and 3 one gig cards.

I hate my Micro drive, because almost everytime i use it I lose a few images... They come up as corrupt or like half of the image is there the other half is grey.

My plan it to replace it with a 4 gig compact flash, and a 2 gig, then keep a good stash of 1 or 2 gig back up cards. I just have to save some money for that.

[FlyingPete]

I have switched all my small cards to 4 GB Sandisk Extreme III cards. I have 4 in total and plan on getting a couple more. I don't know if I will ever get a 8 GB or bigger card. Time will tell.

I think the convenience of having fewer larger cards out ways any potential loss, and this is from someone who just lost a 2GB card!

I tend to buy at the best price point, last time I got a card that was 2GB, currently over here in NZ it is 4GB.

[ssim]

It is amazing how lazy we have gotten with the advances in technology. When I used to shoot commercially in film I was using 120/220 film. I was constantly changing film, it was the nature of the beast. Now it is way easier to change a CF card than a roll of film but some want to get the whole job on one card.

I have around 24GB of CF space. This is across 1 and 2 GB cards. I have had to replace 3 cards due to failure and these have been the top of the line cards in either Sandisk or Lexar (the only two brands I purchase normally). I do have a couple of 1GB microdrive cards. They were some of the ones that I bought when I first started digital and at that time I was buying on price point alone. They have never failed me but they are also the last ones to be used in a commercial shoot.

Failures do happen, I've reformatted cards and had them function properly after that. You do lose confidence in that particular card though. Some have had to be replaced immediately as the failure didn't get rectified through a format. I had one that seemed to work fine but once it got to around image number 80 it would throw the ERR02. My preferred retailer has always replaced the cards for me, no questions asked.

The one thing that you can count on is that if a failure is going to happen, it is bound to happen at the most inopportune time.

Even though I may change cards more often than most because of lower capacity cards I will continue to do it this way. The peace of mind is worth the very minute effort that it takes to change a card and in retrospect is much faster than changing a roll of film.

[lakiluno]

When 2GB cards were uncommon, the same argument was made that you would never want a 2 GB card, but several 512MB cards. So, why are 2 GB cards so reliable now.

When 512 MB cards were uncommon, the same argument was made that you would never want a 512 MB card, but several 128 MB cards.

Long term attention to all this intrigue, indicates that all this concern just does not hold up.

Use larger capacity cards. They require much fewer insertions and removals from your camera and card readers. They require fewer downloads and reformatting. All this should help improve the basic reliabilty of the cards.

Enjoy! Lon

Except your forgetting one thing. The number of gigabytes seen as "standard" varies pretty much directly with the resolution (and therefore filesize) of the camera being used. sure, 512MB cards may of been standard when DSLR's where 3-6Megapixels, but nowadays they are 8-12, so you get fewer shots per card. People probably feel comfortable with no more than 500 photos (in large Jpeg) per card.

[Citizensmith]

1. First lets say a card has the same chance of failure regardless of capcity for this excercise lets say 1 in 1000 hours of use. I cycle my cards so they all get used.
1. a: I own 8 1GB cards therefore there is a 8 in 1000 hour chance of a failure, however it will only affect 1/8th of my images. As statistics go after 10000 hours I would have had 80 failures and lost 80GB of images.

That assumption reads wrong. Sure, in 1000 hours of use your 8Gb card has a 1 in 1000 chance of failure. However using 8 1Gb does not give you an 8 in 1000 chance of failure. Its still only 1 in 1000 as each card was only used for 1/8 of 1000 hours. The chances of any one of your 1Gb cards is only 1/8 in 1000 due to its more limited usage.

So, the chance of a failure is the same no matter what size cards you use. The only difference would be how much data you could concievably loose.

[FlashZebra]

Except your forgetting one thing. The number of gigabytes seen as "standard" varies pretty much directly with the resolution (and therefore filesize) of the camera being used. sure, 512MB cards may of been standard when DSLR's where 3-6Megapixels, but nowadays they are 8-12, so you get fewer shots per card. People probably feel comfortable with no more than 500 photos (in large Jpeg) per card.
My post is an observation regarding the intrinsic reliability of the actual card. Not what humans may or may not "feel comfortable with".

It is very unlikely that the output file size of the camera used has any bearing on the reliability of the physical device.

You may be right about the general warm fuzzy feelings of humans using these devices. But, I have little interest in including such factors into my take on the inherent reliability of said devices.

So, the factor you cite may be important to you, and even possibly many others, but not factoring in the prevailing image capacity of the card was not an oversight on my part.

Enjoy! Lon