Exposure time of 0.04 sec has wrong string representation

[ghost]

This photo.jpg (part of the free Unsplash image set) was taken with an exposure time of 1/25

This sample code reports the exposure time as 0.04 sec:

val metadata = ImageMetadataReader.readMetadata(file)

val exif: ExifSubIFDDirectory? = metadata.getFirstDirectoryOfType(ExifSubIFDDirectory::class.java)

val exposureTimeString = exif?.getString(ExifSubIFDDirectory.TAG_EXPOSURE_TIME)

println(exposureTimeString)

I assume there is a problem with Rational.toSimpleString()

Using this Kotlin method I get the expected string 1/25:

    fun formatExposureTime(seconds: Double): String {

        if (seconds < 1.0) {

            return "1/" + (0.5 + 1 / seconds).toInt()

        } else {

            val roundedSeconds = seconds.toInt()

            val fractionSeconds = seconds - roundedSeconds

            if (fractionSeconds > 0.0001)
                return "$roundedSeconds'' 1/" + (0.5 + 1 / fractionSeconds).toInt()

            return "$roundedSeconds''"
        }
    }

[drewnoakes]

Changing toSimpleString can negatively impact other property descriptions. For example:

diff --git a/heic/metadata/java/Issue 263 dotnet.heic.txt b/heic/metadata/java/Issue 263 dotnet.heic.txt
index f1caa71c..14e9e6f9 100644
--- a/heic/metadata/java/Issue 263 dotnet.heic.txt  
+++ b/heic/metadata/java/Issue 263 dotnet.heic.txt  
@@ -73,7 +73,7 @@ TYPE: HEIF
 [Exif SubIFD - 0xa404] Digital Zoom Ratio = 1.1
 [Exif SubIFD - 0xa405] Focal Length 35 = 28 mm
 [Exif SubIFD - 0xa406] Scene Capture Type = Standard
-[Exif SubIFD - 0xa432] Lens Specification = 4.25mm f/1.8
+[Exif SubIFD - 0xa432] Lens Specification = 17/4mm f/1.8
 [Exif SubIFD - 0xa433] Lens Make = Apple
 [Exif SubIFD - 0xa434] Lens Model = iPhone XR back camera 4.25mm f/1.8

I don't think there's a one-size-fits-all here. For focal length, decimals feel more natural. For shutter and aperture, rationals feel more natural.

To improve this I'd suggest a fix in the descriptor for only the ExifSubIFDDirectory.TAG_EXPOSURE_TIME tag.