photoman022 Loc: Manchester CT USA

Every digital camera manual I've bought always states to format the memory card every time you put it in the camera again. Why do I format my memory card every time I use it? Because the experts at Nikon tell me to. This is probably the only time in life I give blind obedience -- well, there is also my wife...

cyclespeed Loc: Calgary, Alberta Canada

I was assisting, OK being a gofer it is true, for a professional and he asked me to reformat several SD cards on his computer using an App called as you might expect, SD Formatter.
He explained it is free and produced by the SD card manufacturers association. Here is the link.

https://www.sdcard.org/downloads/formatter_4/index.html


It checks for any portion of the card that has become corrupted and blanks it out so file transfer doesn't attempt to use it and the process runs quicker. As stated he then reformatted the cards in his camera so it was ready to receive the images in the most efficient manner. He has never had card problems for the years since using this system and had some serious corruption problems in the past. In short he swears by it.

blackest Loc: Ireland

the card filing system maintains an index of what is used and what isn't. When you delete an individual file the index entry for that file is cleared. When you format a card with a quick format it erases each block in the index if its used or not. Usually there isn't a problem with that but sometimes a block goes bad and then it gets marked as bad and thats not too much of a problem because there usually are some spare blocks that can be used.

There is a limit and after thats reached the card capacity goes down. Some blocks will be bad coming out the factory but because there are more blocks created than are needed you still get the number of blocks they promised you, just less spares.

Ok so if you delete say 50 photo's then 50 entries get cleared in the index, the rest of the card is left alone. Is the free space on that card ok, well thats down to luck more than anything sometimes it is sometimes it isn't. It may have been ok 3 months ago but that doesn't mean it is ok today. So the format will check and clear all the index entries where as the delete in this case just checks 50.
If there is a problem with the card where files have been deleted then you will find out while you are using the card. Its true after a quick format too but everything was ok this morning so its likely it will be ok for your shoot this afternoon.

The cards have individual allocation blocks but they can't be written to individually lets say its groups of 4 blocks it can address (for the purposes of explanation its good enough) so blocks 1,2,3 are used and 4 is free. So to write block 4 it has to read blocks 1,2,3 add the new stuff to block4 erase all 4 blocks and write back blocks 1,2,3,4 much better when it can find 4 blocks free together which is easiest when the card is blank. When the card is getting full it starts to have to write to these part blocks that slows things down.

So yeah you can delete individual files and mostly be ok sometimes its not and the place to find that out isn't in the middle of a shoot and if that index gets corrupted its not just one shot that can be in trouble but a whole card full of images and thats when you start getting posts on boards like this asking how can i recover my photo's as the card says its corrupted.

Oh and if your deleting individual files there is a fair chance you only copied some of your photo's from the card to your computer and if the card goes bad then there is a fair chance the others will be gone forever. At least if your formatting the card then you must copy all the files to your computer to at least one drive. Arguably thats not good enough since if that hdd goes down you lose, thats why i run a raid 1 data drive on my mac pro there are 2 copies of every file that goes on there and if 1 hdd dies and it has happened then i still have the 2nd drive. The fastest way to get safe again is to install 2 new drives raid them and then use the remaining raid slice as a source to write to the 2 new drives. The remaining slice may be on the verge of dying as it is just as old and worn as the drive that died. Even if it is good and has plenty of life left in it rebuilding a degraded raid takes way longer than making new copies.

TechLauren Loc: SW AZ

I delete all photos off the camera card once they are in LR. I only format once when it's new or if I had to reset the camera controls and start fresh.

HOHIMER

I don't always format but, when I do I.............

willaim Loc: Sunny Southern California

It is better to reformat the card in the camera. Deleting it, leaves information that can be recovered. Also, reformatting takes just a matter of seconds. Deleting could take minutes.

Longshadow Loc: Audubon, PA, United States

(I delete mine after Carbonite has backed them up.)

John_F Loc: Minneapolis, MN

Every binary mass storage device has a header section the contains a directory which lists every file and the beginning and ending byte addresses. When you delete a file, its reference in the directory is cleared, but the file data remains in place until rewritten over. By test, I have discovered that successive image file are not perfectly identical in byte size. So if the next picture is larger than the open space the storage control might split the file into pieces and create two directory entries. But I do not expect a camera's OS to be that sophisticated. So that deleting will leave a patch of unusable space.

Reformating erases the directory and creates a new one. My camera does not a choice of low-level or high-level: one just replaces the directory, the other writes zeros over the file writable part of the whole card.

Reinaldokool Loc: San Rafael, CA

Reformating a card not only removes the old file structure, but it also locks out any potentially bad bytes. Formatting erases everything and lays down a whole new file structure. In doing so, it tests the card thoroughly. That's why Sandisk and Lexar (Among others) recommend reformatting frequently--or regularly.

Reformatting will remove even those images that you have locked, so be sure to have saved them.

SusanFromVermont Loc: Southwest corner of Vermont

Please clarify what you are talking about. I am not familiar with the terms "rotating magnetic media" and "flash storage". Thanks!

Apaflo Loc: Anchorage, Alaska

Can you actually quote even one single Nikon manual that says that? I just checked the D810 manual and the D5 manual... there is nothing in either of those saying that.

LannyFeder Loc: Santa Barbara, CA

Think of deleting a file as removing it from the table of contents and the index.

When you go to look for it there is no indicator where it is. The file is still in the same location as it was but you won't see it.

SusanFromVermont Loc: Southwest corner of Vermont

D810 manual, page 366: "Memory cards must be formatted before first use or after being used or formatted on other devices." So while it does not specifically say to format it every time you put your pictures into the computer, it does say that formatting will permanently delete all pictures and other data on the card.

The manuals are not known for fully explaining things they say, but I have heard from various sources that it is better to format (complete erasure) than to delete (thereby leaving image "residue" on the card). I don't usually format every time I move the images to my computer, but continue shooting on that card. Eventually I decide it is time to start fresh! Laziness? maybe Paranoia? definitely - don't want to lose anything until well backed up Fear of wearing out the card? Irrational? perhaps...

blackest Loc: Ireland

Rotating magnetic media your typical hard drive the heads polarize area's on the disk when writing They lay down a series of concentric tracks, the heads have to traverse across these tracks by moving a head on a moving arm a bit like a record player if data is on an inside track for some of the data and an outside track for more of it. the head has to be mechanically moved this takes time and is generally referred to as seek time.

flash memory is solid state transistor memory there are no moving parts data is stored as electrical charges they can slowly discharge over months but usually years. flash is a generic serm for solid state memory (solid because nothing moves only electricity).

SusanFromVermont Loc: Southwest corner of Vermont

Thank you blackest for the explanation. I thought the rotating part sounded like an HDD, but was not sure what the flash meant unless it was a memory stick! So many ways to say the same thing. Still don't really understand how they work, but I do like your description. Lifts a little of the fog...