The values for EXIF fields that are given as fractions are computed incorrectly.

Some examples for BumpassHell_8328.jpg:

- F Number: shown as 0.979034803375, should be 7.2; given as 72/10 according to jhead.
- Shutter speed: shown as 0.97903487118, should be 9.65625; given as 309/32 according to jhead.
- Aperture: shown as 0.914085909977, should be 5.71875; given as 183/32 according to jhead.

Interrestingly, the first two wrong values are the same for seven digits after

the decimal point (0.9790348), but different after that. The last one is also

relatively close, but not that close.