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What's wrong ...?

 
 
Rob
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      12-26-2012
On 26/12/2012 9:51 AM, Alan Browne wrote:
> On 2012.12.25 17:30 , Rob wrote:
>> On 26/12/2012 4:25 AM, Alan Browne wrote:
>>> On 2012.12.25 12:07 , Savageduck wrote:
>>>> On 2012-12-25 07:49:13 -0800, Bror Johansson <(E-Mail Removed)> said:
>>>
>>>>> Every time I insert a card in camera I check if it is empty. If
>>>>> so, I
>>>>> format it.
>>>>
>>>> My thinking is somewhat different. I reformat full, or partially full
>>>> cards once I have assured myself that I have my triple redundant backup
>>>> completed. I never delete image files using the computer.
>>>
>>> You can still recover images from a re-formatted drive using tools such
>>> as RescuePRO.
>>>

>>
>> That will also depend on the method which you formatted the card.

>
> For most cameras it's no issue - eg: if you format the card and it is
> ready in a couple seconds, then it hasn't affected the files at all. And
> that is every digital camera I've ever used.
>
> The 'duck points out that one of his cameras will _optionally_ do a full
> erase format - but it's not the usual mode.
>
>



If I format the card in the camera its readable but if I quick format in
the PC its not recoverable.
 
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nospam
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      12-26-2012
In article <kbdqvf$q6f$(E-Mail Removed)>, Rob
<(E-Mail Removed)> wrote:

> If I format the card in the camera its readable but if I quick format in
> the PC its not recoverable.


then you need a better recovery utility.

a 'quick format' of a card will still be recoverable. all that does is
overwrite the directory. the actual photos are still there. that's why
it's quick.
 
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Rob
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      12-26-2012
On 26/12/2012 7:44 PM, nospam wrote:
> In article <kbdqvf$q6f$(E-Mail Removed)>, Rob
> <(E-Mail Removed)> wrote:
>
>> If I format the card in the camera its readable but if I quick format in
>> the PC its not recoverable.

>
> then you need a better recovery utility.
>
> a 'quick format' of a card will still be recoverable. all that does is
> overwrite the directory. the actual photos are still there. that's why
> it's quick.
>



Not if you are using the for mentioned file recovery programme.
 
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Wolfgang Weisselberg
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      12-27-2012
Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:
> On 2012-12-25 07:49:13 -0800, Bror Johansson <(E-Mail Removed)> said:


>> If remaining space on card is considered 'too small' I delete all
>> files on the card (from the computer)


> Not a particularly good idea. The thing to remember is, no two image
> files are the same file size and that is but one reason random deletion
> by computer can result in subsequent corrupted files on the card.


And in how far does that differ when the camera is the one deleting the files
(which in both cases just means marking the blocks as unused and setting
the first character of the file name to a reserved special value)?

-Wolfgang
 
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Chris Malcolm
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      12-27-2012
Robert Coe <(E-Mail Removed)> wrote:
> On Mon, 24 Dec 2012 22:15:16 +0100, Alfred Molon <(E-Mail Removed)>
> wrote:
> : In article <(E-Mail Removed)>,
> : BrJohan says...


> : > Yesterday I returned home after a trip, carrying with me some 1500 DNG-images on a SDXC-card. After importing to LR4, I saw that ~200 of the imagefiles were corrupt (See attached screenshot). The corrupt images were spread out (seemingly at random) over the days of the journey.
> : >
> : > I have tried reading with different cardreaders and also direct from camera to USB. Same result. Embedded JPEG-previews are OK.
> : >
> : > I have used that particular card-camera combination before without troubles.
> : >
> : > Is the SDXC-card or the camera the primary suspect?
> :
> : Probably more likely the memory card, although it's hard to guess what
> : exactly went wrong.
> :
> : On longer trips I usually carry a notebook computer with me and review
> : the images in the evenings. Therefore the problem you are reporting
> : can't happen to me, because I would detect it in the evening of the
> : first day when reviewing the images. I also review some images during
> : the day when I'm out shooting, to check for instance if they are sharp.
> :
> : Some call this image review 'chimping', claiming that real photographers
> : just shoot and don't review in the field. But the reality is that it is
> : unwise to shoot and blindly rely on the equipment used.


> I hadn't realized that "chimping" is a pejorative term. But in any case, few
> of the pompous pronouncements one hears about what "real photographers" do
> actually come from real photographers.


I don't think chimping is a necessarily pejorative term, although it's
true that some who disapprove of it use it pejoratively. There are
plenty of good professional photographers and photography bloggers who
use the term non-pejoratively. I don't recall any photographer whose
opinions I respect using "chimping" pejoratively

--
Chris Malcolm
 
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Wolfgang Weisselberg
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      12-27-2012
Robert Coe <(E-Mail Removed)> wrote:

> Can you say with absolute certainty that Ingestamatic doesn't modify the
> contents of the memory card in any way?


Noone can say that, not even the programmer:
- Non-trivial programs reuse code (libraries, DLLs, ...) which
would need to be checked.
- The compiler could carry a backdoor which causes it to modify
the contents of the memory card.
- No, checking the compiler sources doesn't help, since you could
put code in it that detects if a compiler is being compiled,
in which case the "if a compiler is being compiled" and the
"if memory cards are accessed" code is put into the new compiler
binary. Then you can excise that part of the source code again,
but the compiler will still carry that backdoor --- and so will
any compiler compiled by it.
- You'd need to check the firmware in the CPU, for it too can
randomly execute embedded code to give compilers a little extra
or to modify the contents of the memory card.
- No, even the write protection on the SDxx card doesn't help.
That's only obeyed in firmware --- which you'd have to check.
Needless to say, said firmware could randomly modify the contents
of the memory card ...
- The SDxx cards do have a flash abstraction layer (FAL), which
does things like wear leveling, ECC handling, clearing whole
erase blocks, remapping real flash write blocks to whatever it
presents the SDxx card reader. Guess what --- it's firmware,
and of course it can modify the contents of the memory card
... oh, and that SECURE in SD means that you're not supposed
to access the secure content (think worried music industry)
which also means they make it hard to read out the firmware
(otherwise you'd know how to access and decode such content ...)
- Let's not forget hard drives --- their firmware can decide
not to deliver exactly what what stored and not to store
exactly what was delivered. So even reading the raw
magnetized domains from the platters of the hard drive
doesn't give you the binary code that's then run on the
computer ...

You'd need to examine every last bit of all of the software and
firmware which compose the complete system you use --- in binary
--- and understand it thoroughly and completely to have any idea
whether there is a modification of the contents of the memory
card *on purpose*. For that purpose, you'd need to understand the
hardware as implemented (with all documented and still undocumented
or even unknown errors), too. Do you have anything urgent to do
in the next couple centuries?

And even then you still can't rule out an α-particle flipped a
DRAM cell (which --- unfortunately --- are about the only part in
your normal computer that doesn't use ECC or even a parity bit,
which would lower (but not eliminate) the chance of that having
an effect)) which caused a unwanted change in the SD card.

> If not, I'd worry that that's where
> the problem lies.


Because?

> Getting the data from the card to the computer is the most
> vulnerable step in anyone's workflow, since there's no backup of any kind
> until it's done.


Ah --- no. You can use a camera with 2 cards and write
simultaneously. You can use an image tank. etc.

> IMO, the best practice is to do the initial copy step in the
> simplest manner available


which means
$ cp -av /media/card/DCIM/* ~/Pictures/$EVENT/

Or maybe compute and compare checksums to ensure the copy seems
correct (and automatically correct it if not):
$ rsync -cav /media/card/DCIM/* ~/Pictures/$EVENT/
(run it until it reports no more files being changed)
instead of using LR or Ingestamatic or whatever else.

> (I
> do my copies with Canon's Digital Photo Professional, and I avoid even
> renaming the image files on the card itself.)


I use cp, and of course, I don't touch the files on the card.
Oh, and my software uses sidecar files, never writing to the RAWs
even further down in the workflow.

> I have nothing bad to say about Ingestamatic. (I never heard of it until you
> mantioned it above and I googled it a few minutes ago.) But it appears to be
> the work of a single author and implements a number of complex features that
> may have obscure side effects. I'd be extremely wary of giving such a program
> direct access to my memory cards. I might feel that way even if I'd written
> the program myself.


Well, it certainly tries to be a jack of all trades instead a
master of one.

-Wolfgang
 
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