To format or not to format

I've been formatting my memory cards in the camera after downloading to PC since about 2002 but I wonder if that's really needed these days.  Early on I'd wind up replacing memory cards about every couple years but the 64GB cards I've been using in my D800E's are more than enough as I've never come close to filling one in a days shooting.  The thing with flash memory cards is that you're limited in the number of write cycles and I'm not really sure if formatting counts as a write cycle or if it alters the write strategy in the flash controller.  

So, instead of formatting the card every time I download I could either erase without format or not erase at all until the space available drops below, say, half.  On a given day of shooting I probably average about 75-100 images which is less than 10% of my 64GB cards capacity so if I left the images for, say, 5 days on the card then format in camera the number of times doing this would be 20% of my current approach.  Using Breeze Downloader Pro I can transfer only the new images so leaving previous days images on the card would be no problem.

So, what's the best approach?


Brian

I am no expert, but I believe deleting images from the card in-camera is a dangerous practice. Even on a computer it is cumbersome and probably causes more shifting of bits on the medium. When you 'format' any storage medium, you are simply deleting its 'indexing' or 'journaling' system, i.e. the filing system which tells the controller where each file or image is located. Thus, your data is still intact and a file recovery program can get all the images from a card even if it has been formatted. This refers of course to the 'quick format' method of formatting which is default in a camera. A 'full format' actually erases everything on the drive, all the files and the journaling system.

After a format, you can fill up and write over the existing data on the card/HD as if it was completely blank. My own practice is to format the card every time I put it in the camera (after having downloaded the images of course). I do it mainly because sometimes I am carrying more than one camera and I may use the same card in a different camera (even if the same make), which then confuses the file numbering system.

One other thing, I sometimes download or look at the images in a program other than LR, which may not have the 'ignore duplicates' option.

Finally, I am so afraid of the card getting corrupted at some point, that I ALWAYS download the images at end of the day, but I am sure most people do this too.


Pradeep

The number of write cycles you can do on your flash cards is more than the days you will live if you were a newborn today

Also formatting only overwrites a tiny portion of the card called the File Allocation Table or FAT.  The actual images are not overwritten until you take a photo that happens to use the same space on the card as a previous photo.

As Pradeep said, formatting is safer than deleting.  When you delete photos you aren't actually deleting them, you are only deleting the pointer to them in the File Allocation table meaning that you are taking that single file and clearing out data out of it, a somewhat more dangerous practice than just erasing the whole file allocation table which is what formatting does.

You are going the wrong direction from a reliability standpoint with your proposed method.

There were three approaches I mentioned and deleting the files from the card was just one of them.  If I have a 64GB card and put, on average, about 5GB per days shooting on it then if I were to retain the files from the four previous days shooting bringing the total usage of the card to, say, 25GB, then if I format the card at that point I'm still formatting but doing so 1/5 as many times.  That way the FAT will be rewritten 1/5 as many times though the amount of the FAT that is changed would tend to be larger.  

The flash controller manages storage so as to use storage in an equal manor so that no one area is used and reused while other areas remain unused.  My question was whether the controller has the ability to do this with the FAT versus the actual data storage area.


Brian

No flash cards do not have TRIM like SSDs do, but who cares, you won't live long enough to ever wear out the card used as camera data storage. Now if you used one as an HD for your OS, you might but never in a camera.

Thanks EJ, I didn't think I'd kill the card in any reasonable lifetime but some sources say a flash cell could have a lifespan of 5000 writes and some others indicate as little as 1000 writes and that would potentially be an issue assuming 125 shoots per year and 8 years use.  Years ago when cards were much smaller I'd tend to replace about every 1-2 years to get a bigger/faster card but at 64GB Extreme SD card I don't see any need to replace for the life of the camera -- perhaps another 5 years or more.

Using Downloader Pro I can download the images from one day and leave them on the card and when I download the next day the files that have already been downloaded are bypassed and not downloaded a second time so there's no real reason to have to format after every download. 
 

Brian

Why would you want to use a card for so long, since technology has moved forward so quickly? A card is one of the more inexpensive item we use today, especially SD cards! I started with SanDisk 2, 4 and 8GB CF cards around 2007 and never formatted or re-wrote on them. I still have about 60 of them. I formatted a couple of them for re-use and found they could not keep up with my newer (old now) camera and buffer for action shots. They're way too slow for modern cameras. I bought 4 32 GB CF Lexar Pros 233x cards around 2010 for $100 each and they write much faster. They are still too slow for my old D700 and its small buffer, if I'm right. Now 32GB Lexar Pros 1066x can be bought in a 2-pack for $97.95 at Adorama! Technology in cameras and cards will certainly be much different in 8 years. Lexar 64GB SD cards can be had for $59.95 a pair in 633x or $79.95 for two 1000x cards. Cameras have much larger buffers now and also write much quicker to the cards so it's harder to outshoot the buffer, but it's nice when the card can keep up with the camera. Everything is changing and old technology won't hold up anymore! Even new card readers are required for many of the newer cards to not corrupt them.

Joe

In 8 years, a card with the same capacity (and probably 10 times as fast) would cost virtually nothing. This is a total non-issue.

After transferring and duplicating to an external drive my images from a CF or SD card, I erase it on the computer and format it in MAC OS Extended, which cameras can't read. That way the camera will prompt me to format the card again and I know it's an empty one, safe to use (if I don't get that prompt I know that non-transferred images are on the card and the remaining capacity is less).

I practiced that for eight years now and still have all the cards I ever bought, in good working condition. And even if a card would die from this every now and then, it'll still be a cheap insurance against loosing irreplaceable shots; not to mention the savings compared to film in the first place.

OK, I'll drop it -- no point beating a dead horse.


Brian

Just one more thing

SD cards have a write-protect switch which CF cards do not. So if you are done with a day's shoot and have not downloaded or want to keep the SD as yet another copy (which I often do), then it's a good idea to flip the switch which will prevent it from being written to again. I also keep them upside down (logo not showing) in my card wallet which also tells me it's been used already.

Pradeep

Primus wrote:Just one more thing

SD cards have a write-protect switch which CF cards do not. So if you are done with a day's shoot and have not downloaded or want to keep the SD as yet another copy (which I often do), then it's a good idea to flip the switch which will prevent it from being written to again. I also keep them upside down (logo not showing) in my card wallet which also tells me it's been used already.

Pradeep

Actually Pradeep, I had a problem with one of my SD cards that when I put it back into the camera I'd get a card error in the camera.  I found the write protect switch was in the write protect position and I had to move it to the write enable position.  But, as soon as I put it back in the camera the switch had slid back to the write protect position.  This happened repeatedly until I put a tiny bit of superglue on it -- doesn't slip on me now, but switching to write protect position will now be more difficult.  

And yes, if you leave images on the card the card then becomes another level of redundancy in case your laptop and/or external HD's dies.  But, I'll leave that lie.  


Brian