Weird EXIF shutter speed issue

I’m not sure if this is the right forum for this question, but maybe someone can help me understand what’s going on with some EXIF weirdness regarding shutter speed. Here’s a photo I took at a shutter speed of 1/640:

darktable shows a shutter speed of 1/640, as does my Linux EXIF previewer. But if you look down below the photo, the Piwigo photo gallery has converted that to a speed of 1/639.

Even stranger, when I upload the photo to eBird:

below the photo it has converted the shutter speed to 104858/67109119! That’s equivalent to 1/639.999990463, but… really? When I browse other photos on eBird, it seems that a similar thing has happened to almost all of my photos, but not to photos contributed by others.

In the grand scheme of things, this isn’t something I’m losing any sleep over, but I’m really curious what is going on here.

If there’s a more appropriate forum for things like this, please point me in the right direction. Since all of my software is FOSS this is just my first place to go to, and I thought maybe someone might have an idea.


Running ‘exiv2 -pv’ on the file shows that the camera actually stored the value in the file as a rational number with numerator 104858 and denominator 67109119, so that is the original value and the ebird site is just displaying it as-is. Most applications would round it to 1/640, but maybe piwigo is truncating it instead.

Ah, that explains it. Thanks. I didn’t know about running exiv2 as a command but that’s a handy tool.

Welcome to the forum, David.
I don’t know much about exif but this is a good place for questions!