Sometimes I see in the Exif exposure value (from a photographic contests site) numbers like 10/4000 or 301/100000.

I guess 10/4000 means 1/400 but what does 301/100000 mean?

Is it due to some Exif read or write error, or is there a meaning that I don't know?

P.S.: If needed I can post some link to photo with this values


1 Answer 1


The values are just fraction. Depending on the camera, you see odd rounding but they do correspond to reality as far as I have seen. You will see the same type of rounding in the EC or exposure bias fields.

10/4000 = 1/400s which is a moderately fast shutter-speed and 301/100000 = approximately 3/1000 = about 1/300 which is just a tiny bit slower. You will often see other extremes such as 30000/1000 = 30s on the long side of exposure.

In my experience, compact cameras tend to produce stranger output particularly because they can use shutter-speeds and ISO values in odd fraction and not the usual 1, 1/2 or 1/3 stops.


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