Format CompactFlash?

I have been taking photos for 20 some years now and have just recently moved to digital. I did a lot of research and read many threads and finally settled on the 40D.
I love it.

My question though is this: Is there any benefit to formating the CompactFlash card each time I remove my images from the card? I have read some things that say there is a benefit and others that say it is not necessary.

Can anyone shed some light on this? Is there a benefit, if so, what is it.

Thanks

If there's a drawback to formatting a card that you KNOW you have copied to a reliable source, I ain't found it.
;-)
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Give me something to shoot

If you never format, you will notice that the estimated remaining shots count will slowly decrease over time. Deleting files only does not clean up the FAT on the card it just deletes the file pointer.

Even if you format and didn't securely transfer your files, you can recover them if you haven't yet overwritten them with new pictures so don't worry too much about that.

There are a couple of good reasons to format the cards in the camera itself before use each time.

First, it's the fastest way I know of to delete the old files and free up as much space as possible on the card.

Second, the camera knows what file system it prefers to use for each card size. The 40D puts FAT-32 on larger cards and FAT-16 on smaller ones. It also selects the proper sizes for the allocation units for each. So it just makes it easy to get it right if you let the camera do it.

I have yet to find any reason not to just format the card in the camera as the easy, fast, safe way to get rid of the old data and make sure the card is prepped for re-use.

But DO make at least one backup of everything you copy from the card BEFORE you format it. It's always good to have at least two copies of everything at all times.

Have fun with it. You'll love digital!

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Jim H.

I always format in-camera, as the camera file system works best that way, and doing so eliminates file fragmentation, which makes it easier to store data, and makes it easier to recover complete data if a card becomes corrupted by swapping, or handling.

I also prefer high capacity cards, and only download images through the camera, but even if you prefer to use a card reader to download your images a hundred at a time, always format your cards in your camera. There is simply no better way to do it.

As others have stated though, never trust just one instance of your images. Make a backup plan, and make it automatic. Offsite backup is a good plan, but don't erase/format your cards until your images are safe at two different locations.

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Voyager

For the past 4 years I have deleted the shots using Downloader Pro and a card reader. Very occasionally I format a card in the camera. So far I have never found a single problem using this method.

if you do then you won't need to format. just checking the delete button will suffice. I have never had to format a card this way. what a pain to have to do that all the time! I've used some cards for years and no need.
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You don't take a photograph. You ask, quietly, to borrow it. Author Unknown

When I used Minolta, I used to format my cards in computer and then in camera every time, but I've been lazy about that since I switched to Canon. No particular reason for either approach in my case.

A couple of weekends ago, however, I formatted my Sandisk cards (Extreme III, 4GB and 8GB) in the computer. FAT32, 32k cluster size (I believe the camera formats using a 4k cluster size for cards up to 8GB).

My write performance increased noticeably; shooting RAW at both ends of the court during a high school basketball game, I almost never had to wait for the buffer to clear.

Interestingly, the performance seemed to drop again after a "delete all" in camera. Can't explain this, unless perhaps the 40D actually formats the card instead of just deleting all the files.

Note that this may not be a good practice for all cards; I've read that some cards have partition offsets that are just screwy enough to slow the camera down because it's always writing across clusters. But it seemed to work very well for me with the two types of cards listed above. I'll be doing that again for sure.

--
geek
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It's not strictly necessary, but it does not harm, and might actually help once in a while. Usually I delete my files after downloading using Downloader Pro, and reinsert the card back into the camera and continue using. I did this for over two years (transferring about once a week) without any problems.

Formatting doesn't actually write over the entire card - that would take much longer than a couple of seconds. It merely clears out the index entries and so on.

Checking the amount of space available on a 2GB card from deleting and formatting, I see a difference of 32KB (formatting gives you 32KB more). That's about 0.5% of a RAW file.

Occasionally file systems could become corrupted, and the easiest way of fixing this is to format it.

Short answer is : whatever you do is fine. Choose a workflow that seems more natural to you.

That isn't a problem at all. For many decades, people have been running from one side of the Cross Bronx Epressway to the other during rush hour. Some continue to champion the move as a serious time saver, while those who were killed along the way don't seem to complain much.

I support personal choice, but some choices are better than others. I think your choice is a bit risky in the long run, but you are welcome to it.

Jovo said:

For the past 4 years I have deleted the shots using Downloader Pro
and a card reader. Very occasionally I format a card in the camera.
So far I have never found a single problem using this method.

Click to expand...

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Voyager

Interesting... If you delete the 'index' on a drive, or card, you can still recover image data that has not been erased. If I format a card in my 30D, or 40D, I cannot recover image data with external apps.

Why is that? Are you certain that your info is current? Do you really know what happens in a 30D, or a 40D when you format a card, or are you just guessing?

I think you might be guessing, and I think you are missing something in the way of current understanding. Show me. Describe in detail how recent Canon DSLR's format their installed cards. I don't mean "repeat what you have been told". I would like for you to offer a school session on how Canon really formats camera mounted cards.

I'm your first student. Tell me, how does Canon do it? No guessing allowed. I want all of the details....

Lenny L said:

Formatting doesn't actually write over the entire card - that would
take much longer than a couple of seconds. It merely clears out the
index entries and so on.

Checking the amount of space available on a 2GB card from deleting
and formatting, I see a difference of 32KB (formatting gives you 32KB
more). That's about 0.5% of a RAW file.

Click to expand...

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Voyager

It's not so much a problem now with the newer Canon ( I can't speak for other brands out there ) cameras on the market.

The older Canon XT , I know there must be a few others that had a problem with the folder system on the card. My XT always creates new folders each time you shoot new pictures, but when you delete them.... the folders remain on the card. After shooting & deleting pictures you can have over 100 empty folders wasting space on your CF card.

JD

Voyager13b said:

Interesting... If you delete the 'index' on a drive, or card, you can
still recover image data that has not been erased. If I format a card
in my 30D, or 40D, I cannot recover image data with external apps.

Click to expand...

Do you mean deleting a file, which in turn means deleting the index entry of the file from the table of contents, instead of deleting the index on a drive?

Voyager13b said:

Why is that? Are you certain that your info is current? Do you really
know what happens in a 30D, or a 40D when you format a card, or are
you just guessing?

Click to expand...

In brief, FAT file system is made up of a few parts. Specifically, the partition record, the file allocation table, the root directory, and data portion.

When you delete a file, what happens is that the first character of the filename is overwritten, and the space it occupied is marked as available. However, all the information of the file is still there. As long as nothing new (e.g. a new file) is written to the device, you can recover everything except the first character of the filename.

If you delete the entire folder, it becomes more challenging to recover the file. But it should still be possible to do so.

If, however, you overwrite the root directory (as when you do a camera format, or a quick format), you overwrite the entire entry. A file recovery program will need to scan through the entire device to search for subfolders, or the actual data itself. I believe I read in your other posts that you use extremely large CF cards, perhaps that may be why it is hard for you to recover images from a formatted card?

I do not know how wear levelling and (to a smaller extent) bad block management, as implemented by the CF controller, may impact the recovery of the data. Anything I post on this topic will be pure guesswork so I won't waste my time and yours by speculating here.

Voyager13b said:

I think you might be guessing, and I think you are missing something
in the way of current understanding. Show me. Describe in detail how
recent Canon DSLR's format their installed cards. I don't mean
"repeat what you have been told". I would like for you to offer a
school session on how Canon really formats camera mounted cards.

Click to expand...

My reasoning is based on educated guess. I do have experience working with file systems at a byte level. It is reasonable (to me) to assume that Canon merely overwrites the partition record, FAT and root directory. To overwrite the entire flash card is unnecessary, time consuming and reduces the lifespan of the card. Even at UDMA speeds, you need 50 seconds to completely overwrite a 2GB flash.

I can find out exactly what happens when a card is formatted, but I don't believe it is necessary to know the details in this case. I can instruct you as to how to discover it for yourself if you are really curious. Instead of doing that, I would suggest you try out some other recovery utilities instead, to see which one can pull your images out of a formatted card. That would be much more useful knowledge. And, sadly, I do not know the answer to this one. I tested a number of recovery applications about 2 years ago, but I've forgotten which one I tried and which worked. In the end I had to do a raw dump of the entire CF and go through it manually.

Sarcasm towards others who don't agree with you does not reflect very well on you. Actually, I'm not even sure what we don't agree about.

Let's see.

1. Formatting is different from deleting. I think we agree here.

2. Formatting does no harm. I think we agree here too.

3. Formatting is good. I agree, more or less. But I won't say it's the same as playing Russian Roulette with your images if you don't format after every download.

Come to think of it, maybe I can convince you that formatting is bad. According to you, if you format, you cannot recover the data. In that case, wouldn't it be better for you to delete rather than format, on the very slim chance you might need to recover your image (say, accidentally deleted from hard disk and discovered before you shot any new photos)?

By the way, I have encountered files corrupted when they are being read using a card reader. Very rare, but it did happen.

I guess the only point we don't agree on is that it is OK to just delete. I think we can both agree to each his or her own on this though.

JD6957 said:

After shooting & deleting
pictures you can have over 100 empty folders wasting space on your CF
card.

Click to expand...

One of the things I like about Downloader Pro. It removes the empty subdirectories as well.

I use a Canon EOS 30D and regular Sandisk 4 GB CF card (no Ultra). Here is how I format the card in a card reader:

format x: A:32k

where x: is the drive of the card

format_cf.dat should be, as seen above, located in the C Root, and should be like this (for EOS cameras):

[Enter]
A[Enter]
EOS_FAT[Enter]
[Enter]

With a 8GB card you can try the cluster size of 64k, it should work, athough I never tested it. Try always to have the biggest cluster size possible.

Why? To undersand it simple: There is a little man inside the camera and he is moving data between the card and camera with a shovel. The cluster size of the CF card defines the size of his shovel. So the bigger the shovel, the faster he can move large amounts of data. The speed incerase is not very high, but still noticeable. By incerasing the cluster size the cards useable capacity gets a little smaller, but there is no big difference, especially when using 4 or 8 GB cards it is only a few images, compared to how much would fit on the card when formated to the standard, small cluster. I belive it is worth the extra speed. I really do not mind if I can store 400 or 495 RAW files. No big deal.

My cheapo Sandisk 4.0 GB CF card is faster, compared to in-camera formating. When I reformat it in the 30D, it is slow again. But deleting images does not affect the cluster size. The most important difference is when I download images from the camera to PC. I never use a card reader. The card is downloaded faster from the camera when it is formatted like this. Also, the read/write process in-camera are faster, but I value the fast download from camera more. I never format the card in the 30D, only do a full delete.
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Erik

I mean 400 vs 395 images.
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Erik

A rather silly analogy! Risk? What risk? Especially since I have taken over 120,000 RAW photos without a single problem. Hold on, perhaps tomorrow my camera will seize up and I will be struck by lightning!

Voyager13b said:

I support personal choice, but some choices are better than others. I
think your choice is a bit risky in the long run, but you are welcome
to it.

Jovo said:

For the past 4 years I have deleted the shots using Downloader Pro
and a card reader. Very occasionally I format a card in the camera.
So far I have never found a single problem using this method.

Click to expand...

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Voyager

Click to expand...

An interesting fact is that even after you have formatted the CF card, the camera can find out the number of the last picture on the card. As far as I remember (it's a couple of years since I last time tried) this is the same happens when you format the card in a card reader.

So evidently the camera writes this information at some hidden place.

AndersLj

In ROM
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Unless Canon has changed everything since the 10D (which I used when I learned about this), it's not fully that simple.

If you took out your normal card and put in another one that had been used in another camera, your camera continued the numbering based on the last image on that card (if that number was higher). This could cause problems, and if you wanted to go back to your "own" numbering you had to perform some tricky operations. Only formatting the card was not enough.

That's the way it was on the 10D. Also, in the user guide of the 40D, Canon mentions that this is what still happens, even if they state that the problem can be solved by a formatting. I have not had any reason to try yet.

AndersLj