Not Your Everyday Banana

by Bart Arondson

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I notice that when taking photos using my camera phone, the file name consists of the date and time. (e.g. 20131101-110015.jpg)

However, most point and shoot and DSLR cameras do not. Their file name is usually in a sequence like DCM0011.jpg

Is there a way that we can set a camera option so that it will create the file with a name that contains the date and time?

With reference to a Point and Shoot Camera Samsung EX1 vs a Camera phone Samsung Galaxy S2

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I for one would love this to be an option! Canon 5D MkIII's have limited file name control but that's more a case of 3 letters... >_> With DSLR's that can take multiple photos per second, the file name gets longer and longer –  NULLZ Apr 10 '13 at 6:01
    
The Brand Olympus has a simple system: it usually starts its names with a 'P' or '_'(don't remember what means but it's related to colorspace), then a digit for the month: 1,2,3,4,5,6,7,8,9,A,B,C, two digits for the day and four other digits for correlative. Thus, file PC083651 was shot on December 8th. It is indeed VERY useful and at least I have never had a problem. It's only odd if you shot during Dec 31 midnight, because "older" file suddenly gets on top of the alphabetically ordered list. Maybe they have a patent and it keeps the rest from doing it. –  Jahaziel Apr 10 '13 at 20:52
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3 Answers 3

up vote 12 down vote accepted

This comes down to software patents — not on dates, but in a way that limits filenames. The only filesystem which is widely available and cross-platform is FAT, the venerable Microsoft DOS filesystem. It works on both old and new versions of Windows, worked on OS/2, works on Macs, works on Linux, and there are plenty of embedded implementations for the mini operating systems that run on cameras. It's old enough that it is public domain.

But, there's a catch. The original version only allowed filenames of eight characters plus a dot plus the three-character extension. The extensions which allow longer filenames are much more recent, and a while back Microsoft was doing some serious saber-rattling over collecting royalties. That means most cameras — and the DCIM standard — take the safe route and avoid code to generate long filenames. And that means human-meaningful date and time isn't viable, because it's just plain too long.

This is backed up by a technical manual for an embedded SD card driver, which notes:

Microsoft offers licensing for the use of its FAT filing system on a per unit sold basis. However it is generally viewed that this only applies to applications that implement the patented long file name system (LFN). It is our understanding that if long filenames are not used then no licence fee is due, however you should ascertain if you agree with this view yourself (to our knowledge Microsoft have not stated this but others have determined this based on original releases of the FAT standard by Microsoft).

Cameras or cameraphones which do write longer filenames have either paid Microsoft, are using a different filesystem, or aren't worried about the legal threat.

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You got it! That is pretty much the restriction. Even dates for cameras that support date file-names are encoded bizarrely with month past October as a single letter to make it fit. –  Itai Apr 10 '13 at 13:04
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FAT32 can support more than 8.3 and is not encumbered as far as I know. Cultural date issues and name sorting is a bigger issue. –  AJ Henderson Apr 10 '13 at 18:57
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@AJ Unfortunately the situation is not so rosy. It's specifically the long filename support in VFAT/FAT32 that is at issue; specifically USPTO 5579517. This was tossed out on review but then reinstated a few years later. The Linux implementation has a workaround which is believed to not infringe (see more on that at LWN), but the most simple workaround is to avoid creating long filenames. –  mattdm Apr 10 '13 at 19:16
    
They could work around this by storing the dates as separate folders, rather than as part of the file name. In fact, that is exactly what my Sony a390 does (though that option is off by default) –  BlueRaja - Danny Pflughoeft Apr 15 '13 at 18:15
    
Actually, FAT only supports 11-character directory entry names. These are commonly displayed as 8+3, but back in the old days, it wasn't all that uncommon to simply use all 11 available characters as the name with no specific extension. Of course, these days, using extensions is commonplace and anything else would at best cause much confusion. –  Michael Kjörling Apr 16 '13 at 11:58
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The reason most cameras don't store files by data and time is simply because no one wrote the code in the camera's software to do so.

One possible reason nobody wrote that code is that the date/time format is illegal according to the DCF standard that describes how cameras should store images for compatibility with other cameras, viewing devices and printers (wikipedia link, actual standard doc).

Another reason nobody wrote the code is that writing code, even seemingly simple code, requires more time than you think (what to do when switching file name modes, what to do when a file with that name already exists, will it work with the software in the CD that comes with the camera? and now you have to test everything twice, once with the old file name mode and once with the date time mode...) - and all this work for a feature that will not sell more cameras - so all that time is better spent elsewhere.

Now, for how to do it with your cameras, a quick search in the Samsung EX1 user manual did not find a way to change file names, so it's probably not possible.

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I think the second paragraph here is the important one: the standard specifies <3 letters>_<4 numbers>, and date and time don't fit into that. –  Philip Kendall Apr 10 '13 at 8:36
    
@PhilipKendall - you can always just not conform to the DCF at all (like his cellphone) - or have two modes, a DCF mode for people who want compatibility with all printers and picture frames and a date/time mode for people who care about file names (and then you get to my 3rd paragraph, the cost of those options is non trivial). –  Nir Apr 10 '13 at 8:44
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@PaulCezanne - I disagree, from an engineering point of view there's only one reasonable date/time format you can use - the number of milliseconds since the UNIX epoch obviously, in UTC timezone –  Nir Apr 10 '13 at 10:17
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I think it introduces to many variables outside of the 'programmers control'. For example, how does the camera respond to 14 shots per second? Also, because time and dates change, it is possible to take a photo, then an hour later, change the time back to an hour earlier, then take a photo. What's the camera to do then? Too many conditions, that a simple incremental file numbers solves nicely. –  cmason Apr 10 '13 at 13:05
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@PhilipKendall - true, but the deeper question is why do the standards specify that. The short answer is cultural agnosticism and proper sorting by name. Also the file creation datetime stamp already captures the datetime as a timestamp that is culture independent. –  AJ Henderson Apr 10 '13 at 18:58
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The main reason is that date formats are also not internationally standard and are not always sortable by order. For example, if I was to view files in order in the US, then mmddyyyy format, then files for March of 2003 would be listed after files for January of 2012. Using a continuous sequence insures that the files will sort by when they were shot when sorted by name. The file's date/time itself stores the datetime in a internationally compatible format and the meta-data on the image itself also contains the information.

One other reason I can think of is that you would need sub-second accuracy for the timing represented. With most DSLRs it is possible to shoot multiple shots per second. My camera for example shoots 6 to 7 shots in 1 second if I hold down the button.

So, in short, the main 4 reasons are to prevent confusion from cultural differences, ensure proper sort order by filename, because multiple photos can be taken per second and because the datetime is already stored through the file creation time.

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Obligatory XKCD: xkcd.com/1179 –  mattdm Apr 10 '13 at 19:44
    
Why a down vote? –  AJ Henderson Apr 16 '13 at 18:50
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