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


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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