How many cards?

[Vivid Color]

At $2.50 per 36-exp roll plus $7 developing with 4x6" prints, the number of shots I took on a recent 3-day family vacation would have paid for a new Rebel with kit lens. 

Exactly. I used to spend a ton of money on film and developing and printing. No wonder I can afford nice lenses now.

But to the OP's original question: I always have two thoughts in mind when deciding how many cards to take with me: 1) How many shots do I think I will take? And 2) It's better to bring home empty cards than not have them with you.

[jdramirez]

I have two 8gb sd cards, 1 32gb sd card, a 16 gb sd, and an 8gb cf 800x lexar.

I have an mkiii and my daughter has a sl1.  As I fill the cf, I'll transfer over to the sd, clear the cf and continue again.

I probably only need the cards, the cf, and the two big sd, but there isn't much of a market for old sd cards, so they hang around.

[RustyTheGeek]

I have a dozen or so 32gb cf cards and maybe 8 32gb 45mb/s SD cards
If I only had 2 or 3 cards I'd have a nervous breakdown

I have to say that I'm the same way.  It depends on how much you shoot and how disciplined you are with offloading your images to the computer.  But I shoot so much over the year that I would go nuts if I had to do that with only two or three cards.  I like to keep images on the card until I've had a chance to take the images all the way to final JPG exports and uploads to my online site.  Then there are several copies and I can easily format the media they started out on from the camera and know the images are safe.  So I also have lots of CF and SD cards that I use often.  YOU CAN'T HAVE TOO MUCH MEMORY!

Avoid potential loss in camera or in the field.  Depending on the number of images I am shooting over the course of a day, weekend or week, I use multiple smaller capacity cards instead of a single large media.  This way, I have something like two media cards per day so if one media were to get corrupted, lost or stolen, I would at least still have half the images.  Imagine if I shot a whole weekend on one media card and lost that single card.  Poof!  Everything is lost.  Where if I were changing cards during the shoots, I would still have maybe 3/4 of the weekend's images in my possession.

Also, when buying cards, watch out for counterfeit cards.  Download some of the verification software and test your cards.  If it's too cheap to be true, it's probably a fake card.

http://sosfakeflash.wordpress.com/
 
http://flashfakecentral.wordpress.com/
 
http://www.passmark.com/support/bit_fake_USB_detection.htm
 

[Northstar]

I have a dozen or so 32gb cf cards and maybe 8 32gb 45mb/s SD cards
If I only had 2 or 3 cards I'd have a nervous breakdown

I have to say that I'm the same way.  It depends on how much you shoot and how disciplined you are with offloading your images to the computer.  But I shoot so much over the year that I would go nuts if I had to do that with only two or three cards.  I like to keep images on the card until I've had a chance to take the images all the way to final JPG exports and uploads to my online site.  Then there are several copies and I can easily format the media they started out on from the camera and know the images are safe.  So I also have lots of CF and SD cards that I use often.  YOU CAN'T HAVE TOO MUCH MEMORY!

Avoid potential loss in camera or in the field.  Depending on the number of images I am shooting over the course of a day, weekend or week, I use multiple smaller capacity cards instead of a single large media.  This way, I have something like two media cards per day so if one media were to get corrupted, lost or stolen, I would at least still have half the images.  Imagine if I shot a whole weekend on one media card and lost that single card.  Poof!  Everything is lost.  Where if I were changing cards during the shoots, I would still have maybe 3/4 of the weekend's images in my possession.

Also, when buying cards, watch out for counterfeit cards.  Download some of the verification software and test your cards.  If it's too cheap to be true, it's probably a fake card.

http://sosfakeflash.wordpress.com/
 
http://flashfakecentral.wordpress.com/
 
http://www.passmark.com/support/bit_fake_USB_detection.htm

Good info Rusty...thanks!

[RGF]

Do you travel?  If you travel, extra cards can save your trip. 

If card goes bad or if you accidentally format it before downloading images, I put it aside and deal with at home.

I have a 12+ 32GB high end cards (Sandisk Extreme / Extreme Pro or Lexar 1000x) plus just added 4 Lexar 800x 64GB.

My goal is a 3 week trip to Africa without having to reuse a card.

[dickgrafixstop]

I'm sitting here staring at a stack of CF and SD cards and thinking "why?".  Backup, availability of original shot,
easy filing, and so forth.  If you consider a 16 gig card holds 500 or so 30 meg shots it's so much cheaper than
film to just store them.  I back up on hard drives, but they go bad too.  By the way - that's also the reason that
I prefer multiple cards  over larger ones - I'd rather have 4  4-meg cards than one 16 meg. 

[Mt Spokane Photography]

I got tired of changing 16GB cards and bought 64GB CF and SD last year. 
 
Now I take the 16GB along with me just in case, otherwise, I use them in my 40D where they will hold far more images that I'll ever take with that body.  I use the 40D for product photography in my studio, it gets used about 3 days a week for 20-50 shots.

[wsmith96]

I have a camera with one card slot, but keep 4 sd cards available.  Personal preference of course, but cards are cheap (relatively speaking) and it makes it easy to keep a few clear for use at all times.

my $.02

[Northstar]

After reading some posts here I decided to order two 16gb lexar 1000x cards for $100. 

You guys sold me on the need to have some extra cards....so now I have 5 total for my two bodies.  (And a dozen plus cards that have been and will continue to gather dust because they've become too small/slow).

[jdramirez]

After reading some posts here I decided to order two 16gb lexar 1000x cards for $100. 

You guys sold me on the need to have some extra cards....so now I have 5 total for my two bodies.  (And a dozen plus cards that have been and will continue to gather dust because they've become too small/slow).

I give my away old cards via sale.  I'll sell a body and I'll throw in a free 4GB/8GB to sweeten the pot.  I suppose it works well enough.

[viggen61]

At the moment I've got a 60d and an mark5dIII.
I've got two Lexar professional 16GB 400x speed SD cards and with the mark5dIII (bought today) I bought a sandisk 16GB 400x speed. At home I thought, why did I buy a card with the mark 5dIII?
Will two cards be enough?

How much shooting do you do? Do you shoot RAW or JPEG? Answering these questions can go a long way to helping you work out whether two 16GB cards are enough.

I know that, for my shooting, that would not be enough. I have, on several occasions, filled a 32 GB card with 18MP RAW images from my 7D. That's around 1,200 RAWs. Of course, many, if not most of those, get culled out later, but when I am shooting wildlife scenes at 8FPS, I can easily fill a 32GB Card.

I recently bought a second pair of 1000x 32GB Lexar CF cards, to give me a total of 4 32GB 1000x, 3 16GB 400x, and an 8GB 400x. That's over 6,000 RAW shots. I'm not sure how many JPEGs that would be, but I'd guess at least 25,000...

For multiple-day trips, I like to be able to use different cards on different days. It seems to help me when I'm importing.

[endiendo]

I have a 5dIII. And had a lot of sd (big, small, fast, slow) cards that I used in my older camera.
For the 5dIII, I bought a big - slow - compact flash, and, in addition to my standard sd cards, I bought a very fast SD card.
fast SD cards are a lot cheaper than fast compact flash..   
I also gave a try to a very fast and expensive compact flash that my wife have for her 7d.

To transfer to computer, I notice no differences. I have an integrated card-reader in the computer, and, of course, fast compact flash goes fast, fast sd goes fast, slow sd goes slow, and slow compactflash goes slow...

I also didn't notice any difference when shooting, with the 5d3. fast sd goes fast, fast compactflash goes fast...that's all. So I try to have always 2 cards in it, one primary, fast, and the other as a "second" when the first is full.

So finally, for me, this debate is a debate about the cost of the cards..

[eli452]

In short the simple answer seems to be "more", I just came across the following http://www.lexar.com/products/lexar-professional-3333x-cfast-card (that's Lexar new 256GB Professional 3333x CFast™ 2.0 card) and the answer can change to "1". 

[neuroanatomist]

(that's Lexar new 256GB Professional 3333x CFast™ 2.0 card) and the answer can change to "1"

That's a whole lot of eggs that will fit in that one basket.  I think I recall my momma saying something about that…   

[jdramirez]

I have a 5dIII. And had a lot of sd (big, small, fast, slow) cards that I used in my older camera.
For the 5dIII, I bought a big - slow - compact flash, and, in addition to my standard sd cards, I bought a very fast SD card.
fast SD cards are a lot cheaper than fast compact flash..   
I also gave a try to a very fast and expensive compact flash that my wife have for her 7d.

To transfer to computer, I notice no differences. I have an integrated card-reader in the computer, and, of course, fast compact flash goes fast, fast sd goes fast, slow sd goes slow, and slow compactflash goes slow...

I also didn't notice any difference when shooting, with the 5d3. fast sd goes fast, fast compactflash goes fast...that's all. So I try to have always 2 cards in it, one primary, fast, and the other as a "second" when the first is full.

So finally, for me, this debate is a debate about the cost of the cards..

Rumor has it that the sd in a mkiii is slow regardless of its speed rating.  I usually just have the cf card in my mkiii and then pop in the sd card to copy over.